quick surf

Quicksurf

Version 5. 1

Surface modeling.

Copyright 1998 Schreiber Instruments, Inc.

All Rights Reserved

Schreiber Instruments, Inc. makes no warranty, either expressed or implied, including but not limited to any implied warranties ofmerchantability or fitness for a particular purpose, regarding these materials and makes such materials available solely on an "asis" basis. In no event shall Schreiber Instruments, Inc. be liable to anyone for special, collateral, incidental, or consequential dam-ages in connection with or arising out of the purchase or use of these materials. The sole and exclusive liability to SchreiberInstruments, Inc., regardless of the form of the action, shall not exceed the purchase price of the materials described herein.Schreiber Instruments, Inc. reserves the right to revise and improve its products as it sees fit. This publication describes the stateof the product at the time of publication, and may not reflect the product at all times in the future.

Quicksurf is a trademark of Schreiber Instruments, Inc. 3D Studio and AutoCAD are registered in the U.S. Patent and TrademarkOffice by Autodesk, Inc. All other tradenames or trademarks are gratefully acknowledged as belonging to their respective owners.

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Contents

Chapter 1: IntroductionAbout Quicksurf .................................................................... 1

Chapter 2: InstallationSystem software requirements............................................... 9System hardware requirements.............................................. 9Required knowledge .............................................................. 9Quick installation................................................................ 10Installation ........................................................................... 10

CD ROM installation .................................................... 10DOS Installation............................................................ 10Windows Installation .................................................... 14

Hardware keys ..................................................................... 17Network considerations ....................................................... 18Customer support................................................................. 19

Chapter 3: ConceptsWhat’s a surface?................................................................. 21

Surface memory ............................................................ 22Parts of a Surface................................................................. 24

Data parts ...................................................................... 25Calculated parts............................................................. 26Break lines..................................................................... 30Contours ........................................................................ 34

Grid Methods....................................................................... 35Continuous Curvature (Standard method) .................... 35Trend surfaces............................................................... 35Kriging .......................................................................... 36

Chapter 4: Quicksurf menus............................................................................................. 37

Chapter 5: Quick StartIntroduction ......................................................................... 43

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Loading the Quicksurf menu................................................43Quicksurf demo mode ..........................................................44Loading the demo data set....................................................44Displaying a surface.............................................................46Examining surfaces in 3D ....................................................50Draping a polyline................................................................51Generating a profile..............................................................52Examining new surface parts ...............................................53Using Boundaries .................................................................54Annotating your map............................................................57

Drawing the contours.....................................................57Indexing the contours ....................................................58Labeling the contours ....................................................58Posting Z values of points .............................................59

Chapter 6: Command ReferenceOrganization.........................................................................61Data input .............................................................................61

Extracting drawing data.................................................62Reading ASCII data files ...............................................65

Data Export ..........................................................................79Exporting ASCII data files ............................................79Exporting 3D Studio files ..............................................81

Surface commands ...............................................................82Show versus Draw.........................................................82

Surface modification ............................................................93Surface Options .............................................................94

Surface viewing....................................................................95Boundaries............................................................................99Annotation..........................................................................102Color control ......................................................................114

Surface colors ..............................................................114Surface Color Sequence...............................................122Set SHOW Color .........................................................129Contour colors .............................................................130

Volumetrics ........................................................................133Design Tools ......................................................................143

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Utilities .............................................................................. 167Elevation utilities ........................................................ 167Quicksurf utilities........................................................ 171Polyline utilities .......................................................... 182Polyface utilities.......................................................... 184General utilities ........................................................... 185

Chapter 7: Configuring QuicksurfConfiguration files ............................................................. 195

List Configuration ....................................................... 196Read Configuration ..................................................... 197Save Configuration ..................................................... 197Factory Configuration ................................................. 197Version Info ................................................................ 197

Configure Grid................................................................... 198Grid Method................................................................ 201Trend method of gridding ........................................... 203Krige method of gridding............................................ 205

Configure Contour............................................................. 207Configure Drape ................................................................ 211Configure Breaks............................................................... 213Configure Extract .............................................................. 214Configure Boundary .......................................................... 218Configure Units ................................................................. 219Configure Camera.............................................................. 220Configure Post ................................................................... 221Configure ASCII Load ...................................................... 223Configure Slopes ............................................................... 225Configure Section .............................................................. 230Configure Surf Ops............................................................ 237

Chapter 8: Surface OperationsIntroduction ....................................................................... 239Surface operations dialog box ........................................... 239

Surface list................................................................... 240Surface management buttons ...................................... 241

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Mathematical operation controls .................................246Surface management functions....................................247

Surface modification operations ........................................250Grid geometry operations ............................................250Surface modification operations..................................254

Mathematical surface operations........................................256Understanding surface operations ...............................256Mathematical surface operators...................................260

Chapter 9: BoundariesBoundary smart commands................................................269Establishing boundaries .....................................................270Nested boundaries ..............................................................271Boundaries and surface displays ........................................271

Chapter 10: Break linesCreating break lines............................................................273Adaptive densification .......................................................274Resolving break lines .........................................................275

Intersecting break lines................................................276When to use break lines .....................................................276

Chapter 11: DrapeConcepts.............................................................................279

Drape basis ..................................................................279Drape step ....................................................................280Draping off the edge of a surface ................................280Drape and Boundaries .................................................281

Using Drape .......................................................................281Solving for an elevation...............................................281Creating a 3D profile ...................................................282Constructing design elements (break lines).................282Converting 2D maps to 3D maps ................................282

Application examples.........................................................283Drape and post points ..................................................283

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Horizontal arc to vertical curve................................... 284Hatch pattern draped on a surface............................... 285

Chapter 12: Surface editingExamining the raw data ..................................................... 287What is an edit point? ........................................................ 288Adding edit points ............................................................. 289Editing contour polylines................................................... 291Correcting slope excursions............................................... 292

Chapter 13: Site planning workflowWorkflow Overview .......................................................... 295

Chapter 14: VolumetricsTIN based volumetrics....................................................... 297

Volume under a triangle.............................................. 297Volume under a surface .............................................. 299

Understanding volume calculation .................................... 300Workflow .................................................................... 301

Volume by Entity............................................................... 303Volume calculation from surface memory ........................ 305

Volume calculation options ........................................ 305Running a volume command ...................................... 309Surface volume ........................................................... 310Area Volume............................................................... 310Boundary Volume....................................................... 311

Practical volume calculations ............................................ 312Comparison to Average End Area volumes................ 314Common volume calculation mistakes ....................... 315

Chapter 15: Surface estimation methodsSupported methods ............................................................ 317

Triangulated Irregular Network (TIN)....................... 317Slope-based methods................................................... 318

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Geostatistical methods.................................................319Which method do I use?.....................................................320

Workflow.....................................................................320Data types and surface methods.........................................321

Chapter 16: 3D Studio meshesExporting mesh objects ......................................................323

Direct surface export ...................................................323Subdividing surfaces....................................................324

Morphing Quicksurf surfaces.............................................325

Chapter 17: User coordinate systemsExtract commands and User Coordinate Systems .............327

Chapter 18: Working with extracted contoursObjective ............................................................................329Workflow ...........................................................................329Extracted contours tutorial .................................................330

Extracting the contours................................................330Correcting slope problems...........................................331Correcting short-cutting contours................................331Edge effects .................................................................334

Chapter 19: Pad constructionObjective ............................................................................335Workflow ...........................................................................336Pad construction tutorial ....................................................337

Chapter 20: Pond construction tutorialObjective ............................................................................343Workflow ...........................................................................344Pond construction tutorial ..................................................345

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Chapter 21: Ditch constructionObjective............................................................................ 355Workflow........................................................................... 356Ditch construction tutorial ................................................. 357

Chapter 22: Wall constructionVertical discontinuities ...................................................... 364Workflow........................................................................... 365

Chapter 23: Road constructionObjective............................................................................ 367Workflow........................................................................... 368Road construction tutorial ................................................. 369

Chapter 24: Slope analysisObjective............................................................................ 385Workflow........................................................................... 385Slope analysis tutorial........................................................ 386

Chapter 25: Contaminant modelingOverview ........................................................................... 391Mapping contaminant iso-concentrations.......................... 391

Chapter 26: Using KrigingIntroduction ....................................................................... 395Objective............................................................................ 397Workflow........................................................................... 397Using kriging ..................................................................... 397

Chapter 27: Geologic faultingIntroduction ....................................................................... 407Constructing fault break lines............................................ 409

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Workflow ...........................................................................410Using Drape and Extrapolate ............................................414

Chapter 28: Architectural uses............................................................................................417

Chapter 29: Configuration files............................................................................................419

Chapter 30: Keyboard equivalentsData input ...........................................................................423

From the drawing.........................................................423From ASCII... ..............................................................423

Data Export ........................................................................423To ASCII.. ...................................................................423To 3D Studio.. .............................................................423

Surface commands .............................................................424Boundaries ...................................................................424Create / Display ...........................................................424Modify .........................................................................424Viewing .......................................................................424

Annotation..........................................................................424Color control ......................................................................425Volumes .............................................................................425Design Tools ......................................................................425Utilities ...............................................................................425

Elevations ....................................................................425Quicksurf .....................................................................426Polylines ......................................................................426Polyfaces......................................................................426General.........................................................................426

Surface operations..............................................................427Surface management....................................................427Surface modification....................................................427File operations .............................................................427

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Mathematical operations ............................................. 428

Chapter 31: Trouble shootingProgram doesn’t run.................................................... 429Menu misbehavior....................................................... 429Data import problems.................................................. 430Extract problems ......................................................... 431Display problems ........................................................ 431Speed problems........................................................... 432Grid problems ............................................................. 433AF pager error............................................................. 433Annotation Problems................................................... 433Lengthy Auto Densification........................................ 434

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Chapter 1: Introduction

About Quicksurf

Quicksurf is a fast, powerful general purpose surface modeling system running inside of AutoCAD Release 12,13 or 14. Thou-sands of people use Quicksurf daily for generation and annotation of contour maps, profiles, sections and volumetric computation.

Quicksurf converts surface mapping data such as point or break line data into contours, grids, triangulated irregular networks (TIN), and triangulated grids (TGRD (pronounced tee-grid)). A suite of sophisticated tools allows you to manipulate modeled surfaces into high quality finished maps and perform a variety of engineering computations.

Quicksurf meets the needs of a broad range of professional disci-plines such as civil, environmental, petroleum and mining engi-neering, geologic mapping and exploration, surveying, photogrammetry and topographic mapping, landscape architec-ture, oceanography and surface visualization.

Quicksurf was designed to operate seamlessly with all AutoCAD applications software. Written in C, Quicksurf is the fastest mod-eling package available running inside of AutoCAD. All of the three-dimensional models produced by Quicksurf are completely compatible with 3D Studio and other three dimensional visualiza-tion packages.

There is no limitation on the number of points or the number of surfaces which may be manipulated simultaneously. Quicksurf utilizes AutoCAD’s virtual memory, so the size of your project limited only by the available hard disk space. Some Quicksurusers have built maps containing over 10 million control pointson the PC platform.

About Quicksurf Page 1


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Quicksurf 5 is available in versions for DOS, Windows, and Win-dows NT running AutoCAD Release 12, 13, or 14.

Input

Data may be input from a wide variety of sources to Quicksurf including:

• ASCII files of X,Y,Z point data• ASCII files of X,Y,Z polyline (break line) data• Extracted from any AutoCAD drawing entities• Direct import of digital elevation model (DEM) data

X,Y,Z point information may be extracted from AutoCAD pointsvertices, 2D polylines representing contours or break lines, veces of 3D polylines representing break lines or profiles, as welmost other drawing entities.

Output

Data generated within Quicksurf may be saved in several wayincluding:

AutoCAD drawing entities: Entity drawn

• Points points• Triangulated Irregular Networks (TIN)lines or meshes• Grids points or meshes• Triangulated Grids (TGRD) lines, or meshes• Contours 2D polylines• Profiles and sections 2D or 3D polylines• Annotation text

Non-AutoCAD formats:

• ASCII point files• ASCII polyline files• 3D Studio mesh files• Binary QSB and QSP surface and polygon files

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Quicksurf surfaces

A surface, in Quicksurf terms, is a mathematical description of a three dimensional surface based on original point or break line data. Surfaces are maintained in Surface memory, which is part of AutoCAD controlled memory, separate from the drawing data-base. Mathematically, a Quicksurf surface is a single-valued function of the independent variables x and y. This means that no part of a surface may be overhanging or exactly vertical, since it would have more than one elevation (z value) at an x,y, point. A surface may consist of any combination of each of the following elements:

• Points• Break lines (Breaks)• Triangulated irregular network (TIN)• Derivatives• Grid• Triangulated Grid (TGRD)

A new surface may be created with just Points as a result of loing X,Y,Z triplets from an ASCII file or extracting points from entities in the drawing with the Extract to surface command. Breaks may be incrementally added to a surface by extractingpolyline entities as break lines with Extract Breaks. The calcula-tion of a surface model with the TIN, Grid, TGRD, or Contour commands create the TIN, Derivatives, Grid or TGRD parts othe surface as needed.

Quicksurf also has the ability to manage an unlimited numberthese surfaces (dependent on your machines resources) with having any combination of these elements. Multiple surfaces allow you to perform algebraic operations between surfaces resulting in surfaces representing thicknesses, cut and fill vol-umes, exaggerated surfaces, slopes and many other possibili

Quicksurf maintains one special surface which is called the results surface or the <.> “dot” surface. When you load data froan ASCII file, or use the Extract to surface command to extract

Introduction Page 3


X,Y,Z data from AutoCAD entities you create a new <.> surface. Any of these actions replace the pre-existing contents of the <.> surface. You may save surfaces as named surfaces with the Sur-face Operations commands.

Quicksurf uses surface memory storage (rather than the AutoCAD drawing database) to decrease the amount of memory required to manipulate data, providing fast execution of modeling operations. Fast and efficient operation in memory provides instantaneous results allowing for thought and analysis to pre-dominate your design process, rather than waiting for calcula-tions.

A surface is stored in AutoCAD-controlled memory, but is not part of the drawing until you instruct Quicksurf to add it to the drawing by issuing a draw response to a Quicksurf command.

A surface will not be visible until you use the specific Quicksurf commands which display surface geometry and their Draw or Show options to display the surface in the current viewport. In the interest of speed the Quicksurf commands of Points, Breaks, TIN, GRD, Triangulated Grid (TGRD), Contour and Post from Memory support the ability to either Show or Draw. Draw pro-duces AutoCAD drawing entities (such as points, polylines or polyface meshes) from a surface model, making them a perma-nent part of the drawing, while Show temporarily displays them in the current viewport (until the next event causing a redraw, like pan or zoom). Using Show allows you to maintain visibility of a model throughout a series of surface operations or viewpoint manipulations without waiting for regens or redraws; once a model is completed it can be incorporated into the drawing with the Draw option of the appropriate command.

Using Show is substantially faster than Draw, but remember a Shown object is not an AutoCAD entity, so it cannot be selected or manipulated with AutoCAD commands and will not be saved with the drawing file when you save the drawing.

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Surfaces in memory will not be saved with the drawing when an AutoCAD Save or End command is executed, but you will be given a chance to save surfaces when exiting the drawing. If you need to save the contents of surface memory, Quicksurf provides a separate command (Write QSB) that allows you to write one or more surfaces from surface memory to disk independently of the AutoCAD drawing. This provides more efficient use of storage (as much as 50% less) and preserves all parts of a surface in a quickly retrievable form.

Surface models

Starting from points and/or break line data, Quicksurf can gener-ate the following basic model types:

• Triangulated Irregular Networks (TIN)• Grids• Triangulated Grids (TGRD)

Contours may then be generated from the TIN, TGRD or Gridsurface model. Any AutoCAD entity may then be draped ontothe surface so it lies on or follows the surface exactly. In this wyou may turn 2D map data into 3D maps or solve for the surfaelevation at any point(s) by draping.

Break line data, representing 3D polylines where surface slopare discontinuous, may be used without limitation on number complexity. Both smooth surface curvature and break line slodiscontinuities may be combined in the TGRD surface model.

Introduction Page 5


Surface estimation methods

TIN models are created using highly optimized Delauney triangu-lation which optimally connects all of the data points. TIN mod-els linearly connect the control points with planar triangular faces. Grid models provide surface estimation between control points and may be created using several different methods includ-ing:

Linear interpolationContinuous curvatureContinuous slopeKriging

LinearExponentialSphericalGaussianPiecewise continuousHole

Surface editing

Any surface may be edited to change its shape to honor your design or interpretation. The edited surface may then be used like any other for volume, slope, or surface to surface computation.

Surface manipulation

Quicksurf can maintain multiple surfaces in memory simulta-neously. Surface algebra may be performed between surfaces, including addition, subtraction, multiplication, division, loga-rithms, relational comparisons, slope calculation and more. Two simple examples of surface algebra are subtracting an existing topography from a proposed topography to calculate a cut and fill surface to be used in volume calculation, or subtracting the top of a geologic horizon from the base of the same horizon to calculate thickness.

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Surface algebra and surface manipulation is performed within the Surface Operations subsystem of Quicksurf. Polynomial trend surface analysis and automatic residual calculation are also avail-able in Surface Operations.

Volumetrics

Fast, accurate volumes may be calculated on one thickness sur-face, between two different surfaces or between a surface and a constant. The volumes may be computed for the entire surface or separately on one or more arbitrary sub-areas.

Construction tools

A broad suite of construction utilities are included to help with your design process. Intersect slope projects a given slope up or down from a 3D control line until it intersects the specified sur-face, then draws a 3D polyline representing the intersection in space. Daylight lines in site planning, fault traces in geology and bench edges in mine design are determined painlessly.

Apply section applies a cross-section template of any complexity to a 3D polyline path to automatically create all of the breaklines for a roadway, including the daylight lines at the head of the cuts and base of the fills. Points on the original topographic surface are automatically moved to a different layer within the disturbed design area.

3D Offset offsets a 3D polyline normal to itself and a user-speci-fied horizontal and vertical distance.

Quicksurf is a not tailored to one specific discipline. We have attempted to give you the fastest, most flexible surface modeler available. As you use Quicksurf, you will find that there are many different ways to accomplish the same end. In this manual we strive to give you the background to quickly use Quicksurf

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productively. We cannot cover everything, so consider attending one of the several Quicksurf courses offered by Schreiber Instru-ments to tune your skills and get the most out of your investment.

Using this manual

This manual is organized into several chapters on concepts, a large command reference, and many specific application exam-ples. Please take the time to read the concepts chapters. Quick-surf is a big, powerful program and you really need to develop a framework to understand and effectively use its capabilities. The command reference chapter is the how-to chapter, stressing syn-tax and command result, rather than concept or tutorial examples. The application examples present small discipline-specific tutori-als of common tasks. A short workflow summary is included in each application example. They do not need to be done in any given order, but some of the more complex ones do build on skills covered in the simpler ones. For example, it will be worth your while to do the simple building pad example before you tackle building an entire road. The troubleshooting chapter sum-marized common problems and their causes.

Typeface conventions

Several different typefaces are used within this manual:

Menu entry or Check box or Edit box

Prompt

User response to prompt

Button

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Chapter 2: Installation

System software requirements

Quicksurf is implemented for operation from AutoCAD Release 12 or 13 for DOS, Windows and 14 for Windows. The program will not run on earlier releases of AutoCAD. Quicksurf is designed to work seamlessly with other Schreiber products such as Spatial Explorer and QuickSurf Pro if present, but Quicksurf has no additional requirements other than AutoCADs.

System hardware requirements

Quicksurf operates within AutoCAD Release 12, 13, or 14 and has no hardware requirements over and above those of AutoCAD itself. If you plan to construct very large complicated models, more memory will allow faster construction times. We suggest the following basic system configuration as a minimum for effi-cient operation:

• 80486 or Pentium processor• 16 megabytes RAM (32MB for ACAD R13)• Sufficient free hard disk space to accommodate your mod• VGA monitor or better

Required knowledge

Effective use of Quicksurf requires a basic working knowledge oAutoCAD. Familiarity with AutoCAD entity types (points, polylines, polyface meshes, text and inserts) and basic use ofviewing commands (Pan, Zoom, etc.) is needed. If you plan to produce hard copy output, knowledge of the Plot, Hide, Shade, and Render commands is helpful. This knowledge may be gained by attending an authorized Autodesk Training Center, guidance from an experienced AutoCAD user, or manual studQuicksurf requires no other specialized training or knowledge.

System software requirements Page 9


Quick installation

Experienced DOS or Windows users may follow these abbrevi-ated instructions. Install Quicksurf by inserting the floppy, typing B:INSTALL and answer the drive and directory prompts. Include the install directory (\QS51) in the ACAD path environ-mental variable if you are running AutoCAD R12 or R13 outside of the Windows environment. If you are unsure about anything, please follow the complete step by step installation instructions below.

Installation

Quicksurf is released on three 1.44-megabyte, 3 1/2-inch disks or on the Schreiber Instruments CD-ROM, with an automatic instal-lation routine. It is similar to the installation program used for Autodesk products, so most users should be familiar with its operation. The installation program will prompt the user for the AutoCAD version and the appropriate drive and directory names for placement of the support files. The installation requires approximately three megabytes of free hard disk space. Installa-tion procedures for DOS, Windows and UNIX are described sep-arately below.

CD ROM installation

If you are installing from the CD-ROM please follow the instruc-tions on the CD label.

DOS Installation

The installation program runs from a floppy disk drive, generally drive A or drive B. The following procedures assume drive B: is the installation drive.

Insert the Quicksurf diskette into disk drive B: and close drive door.

Type B:INSTALL at the DOS prompt and then press Enter.

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The installation program will prompt you for the required infor-mation to complete the installation process. If you decide to quit before the installation is completed, press ESC to abort and return to DOS. Please note that aborting the install process may leave files on your hard disk. When you restart the installation, these files will be automatically copied over (prompting you to allow overwriting of the old files), unless a different drive-directory is specified.

The installation routine first displays the software name and ver-sion number being installed. It then displays the following prompts:

Please choose one AutoCAD release for running Quicksurf:

The flashing selection will be used.

The available AutoCAD releases are shown, with the potential selection flashing. Use the up or down cursor (arrow) keys to highlight your selection then press return to accept it. If more than one AutoCAD releases are run on the same system, the Quicksurf install program may be run a second time.

On which disk drive do you wish to install Quicksurf?

The available drive letters will be shown, with the potential selec-tion flashing. Use the up or down cursor (arrow) keys to high-light your selection then press return to accept it. Quicksurf may be installed on a network drive, but is only valid for one user at a time unless additional licenses are obtained.The next prompt is for a directory for placement of the Quicksurf files.

Please specify the directory on your disk where Quicksurf should be installed: \QS51

We highly recommend you accept the default directory name offered. The path defaults to \QS51, but may be changed to cor-respond to the directory of your choice. If you do choose to place

Installation Page 11


the files in a different place, be sure to alter your ACAD path variable accordingly. After successful input to the these prompts, the hard disk installation process begins.

Unpacking executables...

The files will be copied to the drive and directories you chose. The program and support files will then be expanded from their compressed format.

There is a DOS environmental variable called ACAD which tells AutoCAD where to look for files it needs. You must add the \QS51 directory to this AutoCAD path, so Quicksurf can be found by AutoCAD. If you fail to do this you will receive an Unknown

command error message from AutoCAD when trying to access Quicksurf commands.

The ACAD path variable needs to include the node for the direc-tory in which you installed Quicksurf (such as "C:\QS51").

The ACAD variable is either set by a line in your AUTOEXEC.BAT or in the batch file you execute when starting AutoCAD. For example, a typical SET statement from your AUTOEXEC.BAT or ACADR12.BAT would look as follows:

Setting this variable properly is critical!

SET ACAD=C:\QS51;C:\ACAD\SUPPORT;C:\ACAD\...

Remember that the maximum length of a SET statement is 126 characters. The most common installation problem occurs when AutoCAD is started from a batch file which resets the ACAD path variable sub-sequent to the place where it is set originally (AUTOEXEC.BAT). If you start AutoCAD from a batch file either directly (such as ACADR12.BAT) or indirectly (such as selecting AutoCAD from a menu), you must alter the SET ACAD= statement in the batch file which starts AutoCAD.

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You can confirm the setting of the ACAD variable as seen by AutoCAD by starting AutoCAD, then shelling out to DOS (type Shell followed by two returns), then typing SET at the DOS prompt. This lists the environmental variables including the ACAD path variable. If C:\QS51; is not in the "ACAD=" line, then you have not correctly set the ACAD variable and Quicksurf will not run. Fix it before proceeding.

Installation is now complete.

Convertible demonstration software

Quicksurf is shipped either as a hardware-keyed convertible demo or as an unprotected licensed version upon purchase. In demo mode without a hardware key, Quicksurf only works with the included sample data set and will not import your data. With a Schreiber hardware key installed in a parallel port, this demo version is the same as the full unprotected Quicksurf software. All Quicksurf copies outside of the United States and Canada are required to be hardware locked versions.

Unprotected software

Fully licensed Quicksurf users in the United States or Canada are shipped unprotected copies of Quicksurf, with the understanding that each Quicksurf license is for one concurrent user. Two simultaneous users require two licenses. Additional licenses are available at significant discounts, contact Schreiber Instruments or your dealer for information.



Windows Installation

All versions of Quicksurf should be installed from the main DOS prompt (such as C:>), not from inside of Windows or a DOS win-dow. The installation program runs from a floppy disk drive, generally drive A or drive B. The following procedures assume drive B: is the installation drive.

Insert the Quicksurf diskette into disk drive B: and close drive door.

Type B:INSTALL at the DOS prompt and then press Enter.

The installation program will prompt you for the required infor-mation to complete the installation process. If you decide to quit before the installation is completed, press ESC to abort and return to DOS. Please note that aborting the install process may leave files on your hard disk. When you restart the installation, these files will be automatically copied over (prompting you to allow overwriting of the old files), unless a different drive-directory is specified.

The installation routine first displays the software name and ver-sion number being installed. It then displays the following prompts:

Please choose one AutoCAD release for running Quicksurf:

The flashing selection will be used.

The available AutoCAD releases are shown, with the potential selection flashing. Use the up or down cursor (arrow) keys to highlight your selection then press return to accept it. If more than one AutoCAD releases are run on the same system, the Quicksurf install program may be run a second time.

On which disk drive do you wish to install Quicksurf?



The available drive letters will be shown, with the potential selec-tion flashing. Use the up or down cursor (arrow) keys to high-light your selection then press return to accept it. Quicksurf may be installed on a network drive, but is only valid for one user at a time unless additional licenses are obtained.

The next prompt is for a directory for placement of the Quicksurf executable files.

Please specify the directories where the Quicksurf executables should be installed:

The default will be \ACADWIN for AutoCAD Release 12 or \ACADR13\WIN for AutoCAD Release 13. The Quicksurf exe-cutable files should be placed in the same directory with the AutoCAD executables.

Please specify the directories where the Quicksurf support files should be installed:

The default will be \ACADWIN\SUPPORT for AutoCAD Release 12 or \ACADR13\WIN\SUPPORT for AutoCAD Release 13. This directory is where the menus and associated files are placed.

Please specify the directory where the sample filesshould be installed: \QS51

We recommend you accept the default directory name offered. The path defaults to \QS51, but may be changed to correspond to the directory of your choice. The example files will be placed in the directory you specified here.

After successful input to the these prompts, the hard disk installa-tion process begins.

Unpacking executables...



The files will be copied to the drive you chose. The program and support files will then be expanded from their compressed for-mat.A de-installation routine (RMQS51.BAT) is included which will delete all Quicksurf program files from this directory.

If you have performed a custom installation and placed the Quicksurf program files in a different directory than the sug-gested directories, you must alter the ACAD environmental vari-able to include the node for the directory in which you installed Quicksurf executable files. This need not be done for a standard installation.

When finished, the install program will report:

Quicksurf has been successfully installed.

Convertible demonstration software

Quicksurf is shipped either as a hardware-keyed convertible demo or as an unprotected licensed version upon purchase. In demo mode without a hardware key, Quicksurf only works with the included sample data set and will not import your data. With a Schreiber hardware key installed in a parallel port, this demo version is the same as the full unprotected Quicksurf software. All Quicksurf copies outside of the United States and Canada are required to be hardware locked versions.

Unprotected software

Fully licensed Quicksurf users in the United States or Canada are shipped unprotected copies of Quicksurf, with the understanding that each Quicksurf license is for one concurrent user. Two simultaneous users require two licenses. Additional licenses are available at significant discounts, contact Schreiber Instruments or your dealer for information.



Hardware keys

For international and OEM systems, Schreiber Instruments pro-vides a hardware key. Customers with hardware keys simply plug the key into parallel port 1 or 2 and plug the printer into the key. If you are using hardware keys with a printer plugged in, we recommend that the printer be turned on.

Hardware keys Page 17


Network considerations

The Quicksurf program and support files may be installed on a network drive. As long as the directories containing these files are available on the ACAD path, Quicksurf will function nor-mally. For hardware locked versions, Quicksurf will be in demo mode if accessed by nodes without a hardware key present. A network hardware key for multiple users is being developed for OEM and international use. Contact Schreiber Instruments tech-nical support department for more information.

Please note: On AutoCAD R14 installations on a network server that does not support long filenames you will have to make modi-fications to program filenames for proper operation.

Network installations require either multi-seat licenses or a site license. A single Quicksurf license is for one concurrent user and additional seats require additional licenses. Multi-seat licenses are available at significant discounts from the single seat price. Please contact Schreiber Instruments or your Quicksurf dealer for further information.

Page 18 Network considerations


Customer support

Schreiber Instruments, Inc. provides several mechanisms for technical support.

TELEPHONE (303) 843-9400 8:00 TO 5:00 MST MON-FRIFACSIMILE (303) 843-9885 24 HRS.World Wide Web (WWW) http://www.schreiber.com/ 24 HRS.

Schreiber technical support is provided as a service for our cli-ents. Free technical support is available free via our WWW site. Our toll-free 800 telephone lines go to our sales department and no technical support is available on them.

Free technical support is available via WWW or FAX for all Schreiber products. We endeavor to keep the WWW Tech Sup-port current, informative and containing the latest examples of techniques to help you.

Free voice technical support is available for the first 60 days after purchasing any Schreiber product. After 60 days, free technical support is still available via our WWW or via fax. Voice techni-cal support after the first 60 days is available by purchasing a technical support contract. Questions on installation will be accepted on voice lines and answered immediately at no charge, regardless of whether the 60 day period has elapsed.

Schreiber Instruments, Inc. does not provide technical support for AutoCAD only for Quicksurf. If you have a question related to an AutoCAD function or configuration, or hard copy plotting please call your AutoCAD dealer for technical support.

Include the following on any tech support request:

1. Product name ( i.e. Quicksurf ) and version number (Use the Version selection on the configuration menu of the Quicksurf menu)

2. If the problem can be represented visually, plot the problem

Customer support Page 19


or use the Saveimg command to make a GIF file and utilize email to send your image or data file to [email protected]. We can often answer your question in much less time if we have a picture of your problem. Alternatively you may fax us an image.

3. Certain complex problems may require us to see the data set. In such cases, utilize our bulletin board system to upload your Quicksurf configuration file (.qcf) and AutoCAD drawing file (.dwg) so we can try to duplicate the behavior. Please remove any unnecessary objects from the files to keep the file size as small as possible. Email your files zipped to [email protected] and technical support will respond back in 1 to 2 business days.

4. Have your question well formulated and written down so that all questions may be answered in one pass.

We look forward to answering your questions about Quicksurf. We will endeavor to answer your questions in a timely fashion.

Page 20 Customer support

Chapter 3: Concepts

What’s a surface?

Quicksurf creates and manipulates surfaces. A Quicksurf surface is the mathematical description of a surface which exactly honors all input data points. Quicksurf surfaces are a single-valued func-tion of independent variables X and Y. This means that a surface only has one Z value for any given (X, Y), and so does not model overhanging surfaces or exactly vertical surfaces.

Surface may represent anything. Existing topography, proposed topography, thickness maps, geologic structure maps, concentra-tion distribution, slope maps, pressure gradient maps may all be represented as Quicksurf surfaces. Surfaces may intersect. Overhanging surfaces may be modeled in multiple patches. Quicksurf has no limit on the number of points in a surface or the number of surfaces simultaneously used. The ultimate limitation is available space on your hard disk drive.

Surfaces contain one or more parts such as points, break lines, triangulated irregular networks (TIN), grids or triangulated grids (TGRD).

A surface is not an AutoCAD drawing entity, rather it is a mathe-matical description held in surface memory. Representations of a surface, such as points, contours, grids or TINs may be drawn into your AutoCAD drawing as point, line, polyline, 3D face, polyface mesh or mesh entities. It is important to keep the dis-tinction between Quicksurf surfaces (which reside in surface memory) and drawn AutoCAD entities representing parts of sur-faces (which reside in the AutoCAD drawing database).

All drawing entities created by Quicksurf are placed in their proper position in 3D model space.

What’s a surface? Page 21

Chapter 3: Concepts

Surface memory

Quicksurf creates a unique unit of memory storage inside AutoCAD-controlled memory commonly referred to as a surface. Surface memory has the ability to manage an unlimited number of these surfaces (dependent on your machines resources). Mul-tiple surfaces allow you to perform algebraic operations between different surfaces, resulting in surfaces representing thicknesses, cut and fill volumes, exaggerated surfaces, surfaces representing slopes and many other possibilities.

Quicksurf uses surface memory, rather than the AutoCAD draw-ing database, to store and manipulate surfaces. Although surfaces are stored in AutoCAD-controlled memory, a surface is not part of the drawing until you instruct Quicksurf to add it to the draw-ing by issuing a Draw response to a Quicksurf command such as Contour.

Surface memory versus the AutoCAD drawing

PointsBreaksTINDerivativesGridTriangulated grid

PointsLines2D polylines3D polylines3D facesPolyface meshesPolygon meshes

ASCII point filesASCII break filesQuicksurf QSB filesDEM data files

Surface Memory AutoCAD Drawing

Disk Files

Draw

Extract

Rea

d

Writ

e

Page 22 What’s a surface?

Chapter 3: Concepts

r-ions

rface

rate e and f

A surface will not be visible until you use specific display com-mands (Points, Breaks, Contour, TIN, Grid, Triangulated grid) and their Draw or Show options to either draw or temporarily display the surface in the current viewport. The Show option temporarily displays the requested contours or surface element on your draw-ing screen, until the next AutoCAD Redraw. The Draw option adds the requested contours or surface element to the drawing database as AutoCAD entities.

Quicksurf maintains one special surface which is the results sur-face named <.> “dot”. When you load point data into surface memory it is placed into the <.> surface. The results of any suface operation are placed in the <.> surface. Any of these actreplace the pre-existing contents of the <.> surface. You may make copies of any surfaces or rename surfaces using the sumanagement commands within Surface Operations.

Surfaces in memory will not be saved when an AutoCAD Save or End command is executed. Quicksurf instead provides a sepacommand (Write QSB) that allows the user to write a one or morsurfaces to disk independently of the AutoCAD drawing. Thisprovides more efficient use of storage (as much as 50% less)preserves all parts of a surface in a quickly retrievable form. Iyou attempt to exit AutoCAD with surfaces still in memory, youwill receive an alert and be offered the chance to save them.

What’s a surface? Page 23

Chapter 3: Concepts

Parts of a Surface

The component parts of Quicksurf surfaces can be divided into data parts, which you supply, and calculated parts, which Quick-surf calculates. The following discussion of surface parts relates to the characteristics of the surface parts, not the methods used to create them. Realize that the elevations of calculated parts, such as a grid or triangulated grid, may be computed using different algorithms.

Basic parts of a surface

Points

TIN

Grid

Contoursare not a surfacepart, rather a resultof interpolating on aTIN, Grid or TGRD

Page 24 Parts of a Surface

Chapter 3: Concepts

y

.

upt re

aks ace

w-

Data parts

The two types of data Quicksurf uses to create surface models consist of points and/or break lines.

Points

Points form the basis of most surfaces. Points are unique X,Y,Z triplets in AutoCAD’s World Coordinate System. Point data mabe loaded to surface memory by the following commands:

Extract to Surface (QSX)Merge Extract (QSMX)Read ASCII Points (QSL)Read ASCII Table (QSML)Read QSB FileRead DEM FileLoad Points (with optional Geokit)

The Extract commands extract point data from AutoCAD draw-ing entities. The Read commands read point data from disk filesThe Load Points command reads point data directly from data-base files.

Breaks

Break line data (Breaks) are 3D polylines which represent abrdiscontinuities in the slope of a surface. Examples of breaks athe edges of ditches, walls and curbs in civil engineering and faults in geology. Whereas a surface without breaks maintainscontinuous slope and curvature throughout, a surface with bremay have abrupt changes in slope at the trace where the surfcrosses break lines.

Break line data may be loaded to surface memory by the folloing commands:

Extract Breaks (QSBX)Read ASCII Breaks (QSBL)Read QSB File

Parts of a Surface Page 25

Chapter 3: Concepts

The Extract Breaks command extracts break data from AutoCAD drawing entities such as 2D and 3D polylines. Read ASCII Breaks reads break data from disk files, such as survey data. Read QSB reads break data from Quicksurf surfaces previously stored to disk.

Calculated parts

The calculated parts of a surface are the Triangulated Irregular Network (TIN), Derivatives, Grid and Triangulated Grid (TGRD). Some Quicksurf commands calculate more than one of these parts.

Command Parts calculated

TIN TINGrid TIN, Derivatives, Grid, as necessaryTGRD TIN, Derivatives, TGRD as necessaryContour TIN, Derivatives, Grid, TGRD as necessary

Triangulated irregular network (TIN)

The triangulated irregular network, or TIN, is a three-dimensional model of a surface composed of planar triangular faces. Quick-surf generates it based on the Delauney criterion, by which points are connected optimally to make all triangles as nearly equilateral as possible. The TIN may be used directly for volumetrics, pro-files, elevation analysis, contouring or as a surface to render. Since each vertex of the TIN is a surface point, a TIN honors all the points exactly.

Quicksurf also uses the TIN to identify neighboring points when calculating derivatives for gridded surfaces. Quicksurf can draw the TIN as lines, 3D faces or polyface mesh entities.


Chapter 3: Concepts

Derivatives

When Quicksurf generates a surface where surface curvature is calculated, slope information (1st and 2nd derivatives) are calcu-lated at each vertex of the TIN, representing the slope of the sur-face at that vertex. The derivative order, weighting and blending

The 1st derivatives of a surface represent slope.

parameters affecting this calculation are set within the Configure Grid dialog.

The 2nd derivatives of a surface represent curvature.

Whether or not surface curvature is calculated between control points is based on the Derivative setting in the Configure Grid dialog box. When surface curvature is requested, the derivatives are used to fit a smoothly curved polynomial surface to each tri-angular face of the TIN. By default this polynomial surface has continuous slope and curvature between all neighboring faces of the TIN, except at break lines, where the slopes are allowed to be different on either side of the break line. If a TIN is created from a data set including break lines, the break line information is totally represented in the resulting TIN and derivatives. The TIN, along with derivatives, represent the complete mathematical sur-face description. Both the Grid and TGRD commands use these to solve for elevation at each grid node during surface construc-tion.

Surface curvature

TIN withoutcurvature

Grid withcurvature

Inputdata


Chapter 3: Concepts

Grid

The grid consists a set of vertices, spaced rectangularly in the X and Y axes, with Z values conforming to the modeled surface. Although the mathematical model used honors the input data exactly, the resultant grid model is comprised of cells with verti-ces that are not members of the input point data set. Therefore, the final grid model will very nearly honor the input data set, but may not match the data set exactly. As a smaller grid cell size is used, any error between the input data set and the calculated grid is reduced. As a larger grid cell size is used, the potential error between the input data set and the calculated grid increases. The grid model provides for a smoother representation of the data, when contoured, than a TIN due to the larger number of vertices present for contour interpolation.

Gridding is very effective when dealing with data sets that do not contain break data. The grid does not have the capacity to truly represent break line data due to the fact that the cells have consis-tent spacing, causing the breaks to be smoothed to the grid cell size.

Data sets which contain break lines should be modeled with either a TIN or TGRD, rather than a grid.

Triangulated Grid (TGRD)

The Triangulated Grid (TGRD) model combines the best parts of the TIN and grid models into one continuous model of a surface. The TGRD is used for surfaces which contain both points and break line data, and produces a smooth curved surface away from break lines, but honors break lines exactly.

A Triangulated Grid consists of point data and densified 3D breakline data which have been internally gridded based on the derivative and cell size settings of Configure Grid. The resulting grid node data, along with the breakline data, form a point set which is triangulated to form a special TIN termed a Triangulated


Chapter 3: Concepts

Grid (TGRD). This TGRD is a TIN which honors breakline data exactly, but also may honor curvature data when away from breaklines.

Triangulated Grid (TGRD)

A TGRD surface honors breaklines exactly, with each break line represented as edge of a triangle. Away from break lines, the ver-tices of a TGRD triangles are coincident with where regular grid nodes would have been. The original data points are no longer vertices of the TGRD. The TGRD model produced has smooth grid characteristics (two triangles per grid cell) when away from break lines and behaves as a normal TIN near break lines.

To create the diagram above, first the control points on the sur-face were extracted, then the three 3D polylines representing the edges and bottom of the ditch were extracted as break lines. A triangulated grid was then built with the TGRD command.

The Triangulated Grid may be used for volumetrics, profiles, ele-vation analysis, and contouring. Since each vertex of the TGRD is a surface point, it honors all of the grid nodes and breaks line vertices exactly. Quicksurf can draw the TGRD as lines, 3D faces or polyface mesh entities.


Chapter 3: Concepts

Break lines

A break line is a 3D polyline which lies in the surface along which the slope of the modeled surface is allowed to change abruptly. This enables modeling such features as roads, excava-tions, retaining walls, normal faults and structures.

Under ordinary gridding conditions, Quicksurf will calculate first and second derivatives at all control points based on the elevation values of these points and their neighboring points. These are used in the polynomial equations that will be solved for the z val-ues at the grid vertices. The resulting grid will have continuous slope and curvature (i.e., first and second derivatives) everywhere on the modeled surface. Data near an abrupt slope change will not be honored exactly because of smoothing errors associated with gridding. If we designate the abrupt slope change as a break line, the surface is calculated differently to honor the slope change.

When a break line is encountered by TGRD, both slope and cur-vature are allowed to be different on either side of the break line. When a grid is generated, the break line will form the intersection of two surfaces of different slope and curvature: i.e., an edge. There will be no smoothing errors and elevation data will be hon-ored exactly.

The figures which follow illustrate the effect of adding break lines with the Extract Breaks command on a surface having a V-shaped excavation. A standard grid of the original topography is shown along with the TIN of the original control points. The standard gridded surface (top figure) was generated by extracting the original spot elevations with the Extract to Surface command. This grid shows a rolling surface created by the smoothing pro-cess inherent in gridding with continuous curvature selected. Several 3D polylines representing the edges and bottom of a pro-posed ditch are shown. Extracting these 3D polylines as break lines with the Extract Breaks command produces a TIN, but with no curvature away from the break lines (bottom figure).


Chapter 3: Concepts

Grid of original topography

TIN of original seven points

TIN after ditch break line extraction


Chapter 3: Concepts

Subsequently using the TGRD command produces the accurate reproduction as the triangulated grid. The TGRD surface is a TIN which honors both the grid nodes and break lines exactly.

A TGRD gives the best representation

Grids should not be used with surfaces containing break lines. A grid will average across break line and tend to smooth across the breaks. The figure below shows a grid for this same data set.

Gridding does not honor break line exactly

Breaks may be established by any AutoCAD drawing entity, but 2D and 3D polylines are most efficient. Remember that the break line must follow the elevation of the surface to produce meaning-ful results.


Chapter 3: Concepts

There are two special considerations in break line modeling: ver-tical discontinuities and intersecting breaks.

Vertical discontinuities

Recall that the Quicksurf definition of a surface is a single-valued function of the independent variables X,Y. This means that no part of a surface may be exactly vertical, since it would have more than one elevation value at a given X,Y point.

However, the steepest surface Quicksurf can model is one in which the upper and lower edges are displaced by approximately

drawing units, which is indistinguishable from vertical in most cases. The applications chapter on wall construction dis-cusses methods for approximating vertical surfaces.

Intersecting break lines

Quicksurf densifies all break lines and resolves all crossing break lines during break extraction. When Quicksurf processes a single break line, the elevation of the break line itself furnishes the ele-vation of all densified surface points along it. This produces a potential ambiguity when two break lines intersect over a com-mon X,Y point, yet differ in elevation. Intersecting break lines are representing the same surface, therefore the elevation must be the same at any break line intersection. Quicksurf resolves this by setting the elevation of the surface to the mean of the elevation values on the two break lines. This feature resolves small mea-surement and interpolation errors.

To resolve crossing break lines, Quicksurf must compare every segment of every break line against every other segment. As the number of break lines increases, the computation time increases dramatically.

Stacked data points (multiple control points at a given X,Y loca-tion) along break lines are dropped. Quicksurf resolves stacked data by arbitrarily deleting points from a stack until there is only

109–


Chapter 3: Concepts

one. Break lines made up of multiple polylines joined with com-mon endpoints must be treated as break line intersections, which therefore slows processing.

Contours

Contours are 2D polylines that follow paths of constant elevation on the modeled surface. Contouring is the interpolation of a spec-ified Z value on a TIN, TGRD or Grid model. Although contours are produced from a surface model, they are not inherently part of the surface model. Contours are always generated on the fly from the surface model of the users choice (Configure Contour).

Grid based contours TIN based contours

Contouring from a TIN or TGRD is done via basic linear interpo-lation which interprets each face of a triangle as a plane in space. Contouring from a Grid is done by linear interpolation on the grid cells. This interpolation is performed by solving polynomial equations representing each triangle of the TIN for a constant Z value. In the illustration above, the same area was contoured on the Grid and the TIN. You can see the TIN edge effects on the TIN based contours.

The segment of a contour line within one triangle or grid cell is always a straight line. Grid cell size therefore has a profound effect on the smoothness or angularity of contours.


Chapter 3: Concepts

Grid Methods

A grid may be calculated by many methods within Quicksurf. Each of these methods has several options providing for numer-ous gridding methods.

Continuous Curvature (Standard method)

The Standard method calculates polynomial equations for each individual face of a TIN and evaluates the polynomials at grid vertices that fall under the TIN faces. The user may set the deriv-atives calculated for each triangle to None, 1st or 2nd in the Con-figure Grid dialog.

The results are quite different: Using derivatives set to None results in a grid fitted to the TIN in planar fashion. This method involves no polynomial generation. Grid vertices are simply interpolated against the planar TIN faces. Using 2nd derivatives produces a smoothed surface with continuous slope and curva-ture. This method occasionally may produce surface overshoot problems in areas of very rapid slope changes, but provides excellent results on most data sets.

These continuous curvature methods are the fastest available and provide excellent results when large data sets are to be modeled.

Trend surfaces

The Trend method of gridding allows you to select a particular order polynomial surface and fit it to the entire data set using a least squares fit. You may choose the highest cumulative order of the polynomial in all directions, or specify the order in X and Y directions independently to yield a polynomial with more terms. The selection of a Type 1, first order trend will result only in a least squares fit of a planar surface to the data set. This can be very useful when generating uniformly sloping surfaces to subse-quently drape entities onto. Trend surface and trend surface resid-ual generation are also available as surface operations.

Grid Methods Page 35

Chapter 3: Concepts

Kriging

Kriging is a geostatistical approach to surface generation. Kriging allows the user to design and apply specialized functions to pre-dict the variance the Z value of a surface as a function of distance between control points. The use of kriging requires understanding of semi-variograms and their relationship to spatial distribution of data. When applied without a working knowledge of this theory it is liable to produce inaccurate or deceptive results.

Quicksurf includes interactive semi-variogram design using the Vario command and supports linear, piecewise, spherical, gauss-ian and hole semi-variograms. The kriging tools of Quicksurf are supplied for users already familiar with kriging techniques. This manual does not cover theory related to kriging. Kriging is useful in such disciplines as geophysics, environmental studies, and remediation projects. Users with small contaminant data sets should consider using kriging rather than the standard continuous curvature method.

Grids generated by any of these methods may be used for in any surface operation or for volumetrics, isopachs, profiles, elevation analysis, slope analysis, rendering, or contouring. Quicksurf can draw grids as 3D face, polyface, 3D mesh, or point entities col-ored according to the surface colors options.

Page 36 Grid Methods

Chapter 4: Quicksurf menus

The Quicksurf menus are contained in the QS51.MNU file and its associated menu lisp file QS51.MNL. The Quicksurf menu is added onto the standard AutoCAD menu under the Model pull-down. The root Quicksurf menu is invoked by pulling down the Model pulldown and clicking on Quicksurf, or by clicking on Quicksurf on the right sidebar menu. Either of these actions puts the Quicksurf menu in place of the Model menu.

The root Quicksurf menu contains many cascading sub-menus. Each of the sub menus will be shown over the next few pages.

Quicksurf root menu

Quicksurf menus Page 37


Configuration sub-menu

Extract, import, export sub-menus

Page 38 Quicksurf menus


Surface and color option sub-menus

Boundary and View option sub-menus



Annotate, Design, Volumetrics sub-menus

Utilities sub-menus

Page 40 Quicksurf menus


Utility sub-menus

If you are configured to have a side bar menu present, many of the Quicksurf pulldown commands may be selected directly from the side bar menu. The command function is identical.


Quicksurf

Chapter 5: Quick Start

Introduction

Now that you have Quicksurf installed, we will take about 30 minutes to walk through a basic Quicksurf hands-on introduction. If you have not yet installed Quicksurf, please return to the instal-lation chapter and install the program. Start AutoCAD as you normally do and begin a new drawing.

Loading the Quicksurf menu

Load the Quicksurf menu by typing Menu at the command prompt and navigating in the dialog box to the select the QS51.MNU menu. The menu will be in the \QS51 directory (DOS or UNIX) or the \ACADWIN\SUPPORT directory (Windows).

Pull down the Model menu and click on Quicksurf or choose Quicksurf from the right sidebar menu if present. This will swap out the Model menu to display the main Quicksurf menu.

Quicksurf menu

Introduction Page 43

Chapter 5: Quick start

All Quicksurf commands may be accessed through this menu. You may explore the contents of some of the cascading sub-menus if you wish.

All of the commands referred to in the rest of this chapter will be chosen from the Quicksurf menu, unless otherwise specified.

Quicksurf demo mode

Quicksurf ships in demo mode or as a fully operational package. International customers outside North America will be issued a hardware lock. North American customers will be shipped a ver-sion that does not require a hardware lock. In demo mode all of the data loading functions are disabled except the Terrain Genera-tor and the ability to read the file DEMO5.QSB. This file is a spe-cial version of the Quicksurf binary .QSB surface file and contains a demo data set which includes a collection of surfaces which we will use in this introduction and in the application examples.

When Quicksurf is in demo mode, DEMO5.QSB is the only data file which may be loaded. The Terrain Generator, found under the Utilities -> Quicksurf Utilities sub-menu, can make synthetic terrain surfaces of any number points you specify while in demo mode.

Loading the demo data set

If you get an unknown command message, you have not installed Quicksurf properly. Please see the Trouble shooting chapter.

We will load the surface data from the DEMO5.QSB file which contains point and break line data. These data will be loaded directly into surface memory which was introduced in the con-cepts chapter.

We will load the data using the Surface Operations dialog so we can see what happens. Click on Surface Operations and the dia-log shown on the next page will appear.

Page 44 Quicksurf demo mode


Surface Operations dialog

Select Read QSB file button. This will invoke the standard AutoCAD file dialog. Select the file DEMO from the \QS51 direc-tory, then press OK. This may entail using the left side of the file dialog to change directories to the \QS51 directory, if needed.

The surfaces listed in your dialog box may be different than shown.

After you load the surfaces, your dialog box will look similar to the one above. The listed surfaces are in surface memory, not in the drawing yet. It is important to keep the distinction between surface memory and the AutoCAD drawing database.

At this point, the surface list on the left side of the box shows all of the surfaces which have been loaded from the DEMO5.QSB file. The <.> surface is always present and is listed first. This is called the results or dot surface, and will contain any points or breaks you extract from either the drawing or an ASCII text file or the resulting surface from any surface operation.

There is a surface named Existing on the list which contains the original topography of our demo site. Highlight the Existing sur-face by clicking on the name Existing. Notice that several of the surface management buttons become enabled, including the Detailed button. Press on the Detailed button to see more infor-

Loading the demo data set Page 45


es ur-

e

ks

iew-ny-

are

g

mation about the Existing surface. The detailed surface informa-tion box is invoked which shows that the surface only consists of 167 points and no other surface parts are present. The points sim-ply represent spot surface elevations. They could have come from an ASCII XYZ file from survey information or from points extracted from drawing entities. We will revisit this box as we create more parts for this surface. Press OK to exit the Detailed dialog and then press OK to exit the Surface management dialog.

So far there is nothing in the AutoCAD drawing. Let’s look at the Existing surface and see the various ways Quicksurf surfacmay be displayed. First let’s zoom the view so it overlies the sface named Existing. Use the Surface Zoom command found under the View Options sub-menu to do this.

View Options -> Surface ZoomSurface name <.>:

You are prompted for a surface name. You may enter the nam(existing) or press a question mark (?) to pick from a surface list. Enter a ? followed by a return to see what a surface pick list loolike. Highlight the Existing surface and click OK. The view will be zoomed so the surface takes up about 80% of the current vport. The screen is still blank because we haven’t displayed athing yet.

Displaying a surface

Let’s look at the surface parts one by one. The commands wegoing to look at now (Points, TIN, Grid) are some of the com-mands that can temporarily display surfaces with the show option or make them a permanent part of the AutoCAD drawing usinthe draw option. Let’s look at the original points:

The keyboard command for Points is PNTS.

PointsSurface name <Existing>: Press enter to accept the defaultNone/Show/Draw/Redraw <Show>: S

Page 46 Displaying a surface


-ing

the

The points are displayed as single pixels dots on the screen. The points may be hard to see by themselves, so we will normally show the TIN instead because it is easier to see. These are the locations of the points in the Existing surface. We selected the show option, so the points are just temporarily shown. An AutoCAD Redraw command will remove shown objects. Shown objects such as these points are temporary and are not known to AutoCAD, so you may not select them or erase them with AutoCAD commands.

Perform a redraw by selecting Redraw from the AutoCAD menu or typing:

Redraw

The shown points disappear. Any AutoCAD command that per-forms a redraw (such as zoom, pan, regen, etc.) will remove objects displayed with the show option.

Let’s make the points a permanent part of the drawing:

PointsSurface name <Existing>: Press enter to accept the defaultNone/Show/Draw/Redraw <Show>: D

By answering D for Draw at the Show/Draw prompt we have drawn the points from surface memory into the AutoCAD drawing as point entities. These would be saved as part of the drawif we were to do a Save or End command.

If your display includes a sidebar menu, you may optionally select Quicksurf commands from the sidebar.

Let’s look at some other parts of the surface. First let’s show TIN (triangulated irregular network) for the Existing surface.

TINSurface name <Existing>: Press enter None/Show/Draw/Redraw <Show>: S

Displaying a surface Page 47


de ult rid,

la-

IN ic

The TIN is the triangular interconnection of all of your data points. Showing the TIN is a fast easy way to look at your data set. Now let’s show the grid.

The keyboard command for Grid is GRD.

Grid

Surface name <Existing>: Press enter None/Show/Draw/Redraw <Show>: SDots/Horizontal/Vertical/Both <Both>: B30 x 22 grid built

The grid is calculated by solving for the Z value of each grid nousing a polynomial fit to each triangle of the TIN which honorscontinuous slope and curvature for the surface using the defasettings. Quicksurf includes many other methods to create a gwhich will be examined later.

Contours are not a surface part, per se, rather a linear interpotion on a surface part such as the TIN, Grid, or TGRD. Let’s show the contours.

ContourSurface name <Existing>: Press enter None/Show/Draw/Redraw <Show>: R (to perform a redraw)None/Show/Draw/Redraw <Show>: S

We used the Redraw option of the None/Show/Draw/Redraw prompt to remove the previously shown TIN and Grid. The points remained because we had drawn them.

If you are using the defaults, the contours are displayed basedupon the grid. The Configure Contour dialog will allow you to contour based upon different parts of the model, such as the Tor TGRD. Let’s change the contour interval from the automatsetting to a two foot contour interval and contour again.

Contour IntervalContour interval/Auto <Auto>: enter 2 for a 2 foot contour interval

Page 48 Displaying a surface


ContourSurface name <Existing>: Press enter None/Show/Draw/Redraw <Show>: S

At this very dense contour interval you can see some angular areas in the contours. This is an artifact related to the grid cell size we are using. We will now reduce the grid cell size from about 37 feet on side to 10 feet, recompute the surface and re-dis-play the contours.

The Cell size and Cell count commands clear and recreate a grid in a single command.

Surface Options -> Cell Size

Surface name <Existing>: Press enter Current cell size is <37.21 x 36.86 > (cell size in x, y)Horizontal cell size/Auto <default>: 10 (new 10 x 10 cell specified)Vertical cell size/Auto <default>: 10111 x 81 grid built

ContourSurface name <Existing>: Press enter None/Show/Draw/Redraw <Show>: R (to perform a redraw)None/Show/Draw/Redraw <Show>: S

Notice that the angularity of the contours disappears. Determin-ing grid cell size entails a trade-off between accuracy and file size. A finer grid cell size has less error, but consumes more memory and produces more vertices in the contours drawn.

We can sample the elevation of any surface which has a TIN, Grid or TGRD by using the Track Z command.

Utilities -> Elevation Utilities -> Track ZSurface name <Existing>: Press enter

Move the cursor over the surface and the surface elevation at the cross-hairs is displayed on the top status bar. Press a return to exit the Track Z command.

Until now, we have been only observing the parts of the Existing surface in plan view. Everything Quicksurf creates is actually in its proper position in 3D space. We will now look at these same

Displaying a surface Page 49


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parts in 3D, but first let’s draw a polyline on top of the surface while we are still in plan view. We will drape this line onto the surface later in this exercise. Use the Pline command to draw a roughly horizontal polyline from the left side of the contoured area to the right side. Keep the ends of the polyline within thecontoured area, because this is where the surface is defined.

Examining surfaces in 3D

Now lets change to a 3D view using AutoCAD’s VPOINT com-mand.

VPOINTRotate/ <View Point> <0.0000, 0.0000, 1.0000>: 1,-1,1Regenerating drawing

Zoom Extents to insure the data fills the screen. Remember tpoints are drawn and, therefore, are AutoCAD entities. If we habeen using show only and not drawn any entities, AutoCAD would have reported Extents undefined, zooming to limits. In such a case you may use the Surface Zoom command to coordinate the AutoCAD view and the Quicksurf surface.

Now that we are in a 3D view show all the surface parts again note that they are all represented in full 3D.


GridSurface name <Existing>: Press enter None/Show/Draw/Redraw <Show>: SDots/Horizontal/Vertical/Both <Both>: B

ContourSurface name <Existing>: Press enter None/Show/Draw/Redraw <Show>: S

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Note that the polyline we drew is at an elevation of zero and lies underneath the surface which ranges between 400 and 700 feet in elevation.

Draping a polyline

While we are still in a 3D view, let’s use the Drape command to convert the 2D polyline we drew into a 3D polyline which lies othe surface.

Design Tools -> Drape

Surface name <Existing>: Press enter Return to select all visible orSelect objects: Select the polyline you drew earlier.

The polyline now appears as a 3D polyline following the surfacA redraw is part of Drape, so your shown surface parts disap-peared. Re-display the grid so you can see the relationship between the surface and the draped polyline.


Drape is a very powerful feature of Quicksurf which can changor register any entity onto a surface.

Change back to plan view before proceeding:

Command: PLAN<Current UCS>/Ucs/World: enterRegenerating drawing

Draping a polyline Page 51


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Generating a profile

We can generate a 2D profile of the 3D polyline we just created with drape. We will use the Flatten command to display the pro-file of this draped line. First zoom back (0.5x) to allow room on the display to draw the profile.

ZoomAll/Center/Dynamic/Extents/Left/Prev/Vmax/Window/<Scale(X/XP)>: .5x

Design Tools > Flatten

Return to select all visible orSelect objects: Select the draped 3D polylineSelect objects: Enter

Flatten proceeds through a dialogue to define the graph it will draw. Quicksurf calculates various defaults for some of the parameters based upon the 3D polyline selected. For this exam-ple, just accept the defaults (which may be different than shown) until you get to the Select origin point: prompt.

Vertical multiplier <1>: press enterText size for labeling <7.5>: press enterBase elevation for grid/Auto <Auto>: press enterDraw a grid background <Y>: press enterVertical spacing <10>: press enterVertical labeling interval <2>: press enterHorizontal spacing <20>: press enterHorizontal labeling interval <5>: press enter

Select origin point: Select a point near the bottom left of your screen

Now the profile will be drawn as a graph of elevation vs. horizon-tal distance along the polyline. Quicksurf flattens the 3D polyline into a 2D profile in the XY plane, displaying the distance along the 3D polyline in the X axis and the Z elevation in the Y axis of the resulting 2D profile.

Zoom as necessary to examine the profile. When finished, erase the draped polyline and profile, as we won’t need them further

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Examining new surface parts

Using the TIN, Grid and Contour commands, we created addi-tional surface parts. When we first looked at the Existing surface it only contained points. Let’s use surface operations to look athe Existing surface again and see what parts have been creat

Surface Operations

Before we invoke the Detailed box, notice that the Existing sur-face now has more parts listed after the surface name. Wheretially only the letter P (for Points) was listed, now the list includesP TDG indicating that a TIN, Derivatives and a Grid were built. A Quicksurf command will generally build the parts it needs automatically. For example, if a surface contains only points and yissue the Contour command, the TIN, Derivatives and Grid will be automatically created, as required.

Highlight the Existing surface by clicking on the name Existing, then press on the Detailed button.

Detailed Surface information

Examining new surface parts Page 53


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In addition to the points, the TIN and Grid portions of the dialog box now contain information. The minimum and maximum val-ues of X,Y, and Z, along with plan and surface areas and the vol-ume between the surface and the zero (XY) plane are shown. The slope extremes shown for the TIN, TGRD and Grid commonly show a steep maximum slope. This may be reflecting one small edge triangle or grid cell which has an abnormally steep local slope.

The detailed surface information dialog is the first place to look when you have a misbehaving surface. Often the minimum and maximum values for the points will indicate erroneous input data. Press OK to exit both of the dialogs.

Using Boundaries

You may limit the area in which points, TINs, grids and contours are displayed by specifying one or more closed polylines as boundaries with the Boundary Options -> Set Boundary com-mand. The boundaries may be nested. Boundaries are very useful for presentation purposes and volumetric limitations. If you attempt to display parts of a surface and don’t see anything, ymay have a boundary set which does not overlie the surface odisplay area. We will draw several polygons to be used as boaries.

First zoom the viewport to register over the Existing surface.

View Options -> Surface ZoomSurface name <Existing>: Press enter

Show the TIN to see the extents of the Existing surface.


Draw a rectangle within and somewhat smaller than the area ered by the TIN. We will use this as a boundary.

Page 54 Using Boundaries


Command: RECTANG

First corner: select lower left pointSecond corner: select upper right point

Select the rectangular polyline you just drew as a boundary.

Boundary Options -> Set BoundaryReturn to select all visible orSelect objects: Select the rectangleSelect objects: Press enter4 points extracted from 1 polyline

Show the contours to see the effect from the boundary.

ContourSurface name <Existing>: Press enter None/Show/Draw/Redraw <Show>: Redraw to remove the shown TINNone/Show/Draw/Redraw <Show>: S

Notice that the contours stop at the boundary. Boundaries may be complex polylines and also may be nested. Draw a closed polyline shaped like a peanut inside of the rectangle with the PLINE command. Remember to end the PLINE command with a c to close the polyline.

Now run the Set Boundary command again.

Boundary Options -> Set BoundaryShow/New/DIsable/Enable/DElete/Read/Write <DI>: Enter N for NewReturn to select all visible orSelect objects: Select both the rectangle and the peanut polylineSelect objects: Press enternn points extracted from 2 polylines

Notice that once a boundary has been set, the Set Boundary prompt includes more options. In this case, we are specifying a new boundary definition.

Using Boundaries Page 55


Now show the contours again.

ContourSurface name <Existing>: Press enter None/Show/Draw/Redraw <Show>: Redraw to remove the old contoursNone/Show/Draw/Redraw <Show>: S

Now, with nested boundaries, the contours appear between the boundary polygons. You may want to experiment with other combinations of closed polylines as boundaries.

Now show the grid with the boundary enabled to observe the effect of the boundary on the grid display.


Elements such as grid cells or TIN faces are either shown in their entirety or not shown at all; they are not clipped at the boundary.

Important: Before moving on, disable any boundary you may have set, so the entire surface will be displayed.

Boundary options -> Set BoundaryShow/New/DIsable/Enable/DElete/Read/Write <DI>: Enter DI to disable

Perform a Redraw to remove the shown surface parts, then erase the boundary polylines before proceeding.

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Annotating your map

Next we will draw, index and label the contours, then post the Z values next to the points. We will create a display similar to the one shown below, but for the whole surface.

Indexed and Labeled Contours

Drawing the contours

Until now we have just been showing the contours. The contour annotation commands (Index and Label) only work on drawn contours (2D polylines), so let’s draw the contours, first resettithe contour interval back to automatic.

Contour IntervalContour Interval / Auto <2>: enter A for automaticContour Levels / Auto <20>: enter 20 for 20 contours over the Z range

ContourSurface name <Existing>: Press enter None/Show/Draw/Redraw <Show>: D (to Draw as polylines)Close all? <N>: Press enter (option explained in command reference)

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Indexing the contours

Use the Index command to widen selected index contours.

Annotate -> Index Contours

Index interval <100>: Press enterIndex layer <unchanged>: Enter to leave index contours on same layerIndex width <1.0>: Enter 4 for an index contour width of 4 drawing unitsReturn to select all visible or Select objects: Press enter to select all of the contours

The 100 foot index contours will be redrawn 4 units wide. Note that the index width is in drawing units, so the proper width to choose will depend on the scale of the drawing. If you are unsure, you may indicate the width graphically by pointing.

Labeling the contours

Now we’ll label some of the contours with elevation values. Contour labeling is interactive; simply pick the contours to be labelled at the desired label locations when prompted.

Annotate > Label Contours

Label location: Select several locations with the cursorLabel location: Press return when done selecting locationsText height <0.2000>: Enter 15 or specify a height by pointing

Elevation values will appear on the contours at the selected sNote again that the text height must be chosen according to ding scale. This command uses the current AutoCAD Units and Style settings which can affect the number of decimal places dplayed and the font size.

For labeling large numbers of contours you will use the Auto-Label Contours command, which is described in the CommandReference chapter on page 112.

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Posting Z values of points

Now we’ll post elevation values next to some of the points. Quicksurf can either post the Z values of the points directly fromemory (Post) or post the elevation of the drawing entities (Drawing Post). We will use the Post command to post the Z val-ues of the points directly from memory.

Annotate -> Post from memorySurface name <Existing>: Press enter None/Show/Draw/Redraw <Show>: D

Zoom as necessary to view the posted values. The Post from Memory command uses the settings from the Configure Post dia-log box to determine the text location, height, rotation and justcation for the posted Z values. Post supports the Show/Draw display option so you may preview your settings. The numberdecimal places shown to the right of the decimal point dependupon the AutoCAD Units command settings. If your posted val-ues need adjusting, you may need to change these settings.

Any boundaries in effect are honored by Post from Memory. The Z values are drawn as text on the current layer unless a specilayer has been associated with the surface being posted via thDetailed surface operation dialog box.

Over-posting of text may occur in densely populated areas of drawing. The AutoCAD Move and Rotate commands are useful in resolving such problems.

This quick start introduction barely scratches the surface of thcapabilities of Quicksurf. It is designed to give you the concepof a surface, independent from the drawing, and to taste the 3functionality of the program. Break lines, surface operations including surface to surface algebra, volumetrics, and many ottools are discussed in the following chapters.

Annotating your map Page 59

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Chapter 6: Command Reference

Organization

This section describes each Quicksurf command. You should be familiar with the material covered in the concepts chapter before using this section. It is divided into the following groups based upon command function.

• Data input• Data export• Surface commands• Surface modifications• Surface viewing• Boundaries• Annotation• Color control• Volumetrics• Design tools• Utilities

Many of these commands are influenced by the current configration settings. Those are described in the next chapter on Config-uring Quicksurf.

Data input

Quicksurf surfaces are generally created from input data consing of points and/or break lines. Points may be read from an ASCII file, extracted from AutoCAD drawing entities or read directly from a database manager using the optional QuickSurf Pro extension. Break line data may similarly be read from an ASCII file or extracted from 3D polylines in your drawing. Datin ASCII files consist of X, Y, Z data from any source, such astotal stations for survey data, log depths for borehole data, cocentration values for ore or contaminants, or measurements frgeophysical surveys.

Organization Page 61

Chapter 6: Command reference

Extracting drawing data

Extract to surface

QSX

The keyboard equivalent of each command is shown at the right margin.

Extracts X,Y,Z points from AutoCAD drawing entities and loads them into the results < . > surface. This will delete the current contents of the < . > surface and create a new < . > surface con-taining just the newly extracted points.

Extract from drawing -> Extract to surface

Return to select all visible orSelect objects: select

Objects may be selected with the normal AutoCAD selection methods. Pressing enter will select all visible entities on screen. Use the Return to select all visible prompt with caution as you may extract elevation information from unintended entities (such as TEXTs or INSERTs).

If you want to add points to an existing surface, use Merge Extract.

Objects will be extracted as follows:

Points Directly2D or 3D polylines: One point per vertex *Circles One point at center *Arcs One point at each endpoint *Shapes One point at the insertion pointSolids or traces One point at each corner3DFACES One point at each cornerInserts (blocks) One point at the insertion pointText One point at the insertion point3D polygon mesh One point at each grid node in the mesh3D polyfaces One point at each vertexLines One point at each endpoint*

* These entities may be optionally densified with additional vertices during extraction using the Densify during extract option of the Configure Extract dialog box.

Page 62 Data input


Entity extraction is controlled by the settings in the Configure Extract dialog box. Within that dialog you may select auto-densi-fication of lines, arcs, polylines and circles during the extraction. You may also filter which entities you extract by entity type, layer or z value of the entity. These are described fully under the Con-figure Extract section on page 214.

All entities are extracted in the AutoCAD world coordinate sys-tem by default. Refer to the User Coordinate System chapter if you need to extract in user coordinates.

Merge extract

QSMX

Merge extract functions exactly like Extract to surface with one major difference: Merge extract incrementally adds the extracted points to the results < . > surface, as opposed to Extract to surface which deletes the existing < . > surface and creates a new one.

Extract from drawing -> Merge extract


Use Merge extract to incrementally add points to the < . > sur-face. Use Extract to surface to create a new results < . > surface.

Extract breaks

QSBX

Extracts break lines from the drawing and adds them incremen-tally to the results < . > surface. Typically it is used after Extract to surface or Merge extract, but may be used by itself if the sur-face is composed only of break lines with no points. A break line is a line of slope discontinuity along which the slope of the mod-eled surface is allowed to change abruptly. This enables you to

Data input Page 63


model such features as normal faults, mine pits, cuts, fills, retain-ing walls and structures which have abrupt edges. Break lines are most commonly represented in the drawing as 3D polylines.

Extract from drawing -> Extract Breaks


Using a curve error of XXXXUsing a step of XXXXX break lines extractedXX stacked points droppedChecking existing surface dataFinding new intersections...Resolving intersections...Adding break line points...Auto densification...XX triangles built (may be repeated many times on complex models)XXXX additional points added to the current surface

Objects may be selected with the normal AutoCAD object selec-tion methods, or all visible objects may be selected by pressing enter at the Select objects prompt. Objects are extracted in the same manner described for the Extract to surface command.

The following entity types are extracted and automatically densi-fied by Extract Breaks:

Line2D or 3D PolylinesArcCircle3D Face Edges become breaksTraceSolid Non-extruded edges become breaks

All other entity types are ignored. The results of Extract Breaks is dependent upon the settings in the Configure Extract dialog covered in the next chapter. Within that dialog you have control over break line densification and curve error tolerances.

Page 64 Data input


The Break lines chapter (page 273) describes how Quicksurf uses adaptive densification to create new vertices in your surface. It also covers how break line intersections are resolved and the time required.

Always use the TIN or Triangulated Grid command, not the Grid command, when modeling a surface containing break lines, as a TIN or TGRD honors break lines exactly, but a Grid only approxi-mates break lines. Likewise, contours created from surfaces con-taining breaks should always be generated based on the TIN or TGRD, not the Grid, to insure that the breaks are honored exactly.

Reading ASCII data files

Read ASCII Points

QSL

Loads one surface at a time from an ASCII file of free-form x,y,z data into the results < . > surface. Input files must be in ASCII with data values arranged by column. Any non-numeric character string is considered a delimiter. The default format is three col-umns representing x,y,z values respectively; other columnar arrangements may be set within the Configure ASCII Load dialog.

Import Data -> Read ASCII Points

File name <>: Drive/path/filename.extN points extracted from file filename.ext

This command does not assume a default extension for the file-name; if the filename has one, you must enter it.

External files are basically free-field ASCII text files consisting of a sequence of lines. Each line consists of numbers delimited by spaces or any non-numeric characters and terminates with either a line feed or a carriage return/line feed sequence. Each line must contain at least three numbers expressed as ASCII text, express-ing the x, y and z coordinates of a control point. Standard deci-

Data input Page 65


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mal or exponential notation may be used to express x, y, z coordinate values in the input file. Any group of characters that cannot be interpreted as a number may be used to separate the three values on a line. Therefore, spaces, tabs, commas, semico-lons, parentheses, etc. are all valid data field separators (delimit-ers). By default, files are assumed to have three columns of data for x, y and z respectively.

The Read ASCII Points command parses each data line as described above. It is important to realize that if you have more than three columns of data and some of the columns have missing data, this loader is inappropriate. For example: assume you have four data values separated by commas and are loading columns 1, 2, and 3. If a line in the file has no data (e.g. blanks) for the third value, the fourth value is used because it is the third valid number on the line. In such cases, use the Read ASCII Table command.

If you need to load more than one surface at a time or have delim-ited or fixed-field data or multi-column data containing ’holes’ (fields with no data), use the Read ASCII Table (QSML) com-mand instead of this Read ASCII Points (QSL) command.

Rarely you may encounter a file that appears correct, but doesload properly. This can be caused by non-printing charactersembedded in the file or by non-standard line terminators. Thecan be encountered when receiving files from different platformA quick fix for these files is accomplished by reading them intoword processing program and writing them back out as a text fiMost word processing programs automatically strip offending characters.

Page 66 Data input


Configure ASCII Point load

Read ASCII Points supports alternate column order and scaling of the values in your input file. You may scale x, y, or z indepen-dently during loading using the settings within the Configure ASCII Load dialog box.

If there are additional columns, or the columns are not in x, y, z order, or you want to scale the data, this command will allow you to define an alternate format.

Configure ASCII Load

Note: These options only effect the free-form Read ASCII Points command, not the Read ASCII Table command.

This invokes the Configure ASCII Load dialog box.

ASCII Load configuration dialog

ASCII file

Specify the file containing the ASCII data to be loaded into the results < . > surface. This command does not assume a default extension for the filename; if the filename has one, you must enter it. A full path may be included if needed.

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Data column position

Specify the three data column position numbers by setting the column numbers that contain the x, y and z data. For example, if a file contains four columns representing point number, northing, easting and elevation. The x, y, z column numbers should be set to 3, 2, 4 respectively.

Scale factors

Next specify any scale factors you wish to use during data load-ing. X, Y and Z values may be scaled independently during loading into surface memory. This is handy for data sets express-ing x and y in units of feet and Z in units of meters or vice versa.

The options set in this command are preserved in the configura-tion file if you save one. This command only sets the options for data loading by Read ASCII Points. The Read ASCII Points com-mand actually loads the points into surface memory.

Spreadsheets, database report generators, application programs, surveying data collectors, laboratory data acquisition systems, word processors and text editors can create ASCII input files suit-able for use with Quicksurf.

Read ASCII Table

QSML

The Read ASCII Table command is designed to load single or multiple surfaces from an column oriented ASCII file in one pass. It can read delimited or fixed field data structures such as those exported from spreadsheets, database managers or total stations. If you have columnar data containing ’holes’ (where no surfacvalue was recorded), the Read ASCII Table (QSML) command will load these properly, whereas the Read ASCII Points (QSL) command will not.

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The Read ASCII Table command reads the ASCII file, writes a QSB file with the same filename, then loads the surfaces into sur-face memory. Unlike the Read ASCII Points command, which loads into the results < . > surface, Read ASCII Table loads into named surfaces and leaves the results < . > surface unchanged.

An associated keyboard command, ASC2QSB, reads the ASCII file and writes a QSB file, but does not load the surfaces into memory.

Read ASCII Table is designed for data sets which have multiple z values for each x, y location. Information from vertical drill holes (tops, thicknesses, saturations, concentrations) or repeated samples over time at the same location fall into this category.

Import Data -> Read ASCII Table

Read ASCII Table invokes the standard AutoCAD file dialog and allows you to select the desired ASCII file for surface loading. The input file format should look as follows:

X,Y,Z1,Z2,Z3,Z4,... One X,Y location per line

X and Y represent the map view location and Z1, Z2,... represent the Z elevation of each successive surface. Quicksurf will create a surface for the Z1 values using a point for each (X,Y,Z1) where Z1 is a valid number. The Z2 surface likewise consists of the point set of (X,Y,Z2) points, and so on for all Z values specified. Each line in the file should contain the same number of Z fields. If no data is present for a given X,Y then a blank or null field should be given in the input file.

Loading surface data from a QSB or ASCII file always reloads all of the surfaces in that file into Quicksurf surface memory and replaces any surface with the same name. You may sequentially load surfaces from several different files and paths, but keep in mind that if two surface files have surfaces with the same name

Data input Page 69


n, tion f and

only the values for that surface from the last file read will be in surface memory. Loading the same surface name twice is a replace operation, not a merge.

Read ASCII Table is flexible enough to handle many different data formats as illustrated by the following examples:

Sample ASCII data file with no heading line:

527,1028,12.5,20.92,35473,1181,18.5,18.55,28581,1629,29.2,25.13,43482,1163, ,17.93,32 Z1 missing522,1073,18.1,21.73, Z3 missing495,1278,,,36 Z1 and Z2 missing519,1186,13.8,19.92,23

In the above example four surfaces would be loaded. X and Y are in columns one and two respectively, with the first Z value in the third position. This Z value in the third column becomes a point in the first surface (S1). Because there are no surface names defined in this file, the default names of S1, S2, S3, and S4 will be assigned. Surface S1 will have five points in this example, because the fourth and sixth record don’t contain a Z value.

Assigning Surface Names

When you read an ASCII file with no surface name informatiodefault names of S1, S2, S3, ... are assigned. You have the opof supplying a header line containing a comma-delimited list osurface names. This header should be the first line in the file start with the character string “#X,Y,” followed by a comma-delimited list of your surface names.

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For example, the following ASCII file would load three surfaces named Topography, Piezometric, and Bedrock.

#X,Y,Topography,Piezometric,Bedrock552,1026,1560,1541,1450637,2931,1610,1565,14821245,831,1592,1572,1502...

Changing delimiter and quote characters

By default, the delimiter character is a comma (,) and the quote character is a quote mark ("). These may be redefined if needed by adding a special line at the beginning of the ASCII data file you are going to read. The special line must occur before any data line and consists of a keyword followed by a space followed by the substitute character. The two keywords are #Delimiter and #Quotemark.

For example, if the previous dataset used a pipe symbol (|) as a delimiter and a single quote as the quote character (’) the file would look as follows:

#X,Y,Topography,Piezometric,Bedrock#Delimiter |#Quotemark ’’552’|’1026’|1560|1541|1450’637’|’2931’|1610|1565|1482’1245’|’831’|1592|1572|1502...

Quote characters are not required and are supplied for compaity with other software packages. Quote characters allow for imbedded delimiter characters within one field. The entire texstring within the quotes is considered one field. Any charactestring within a field is used if the first character(s) convert to anumber successfully and is assumed to be missing data if it dnot. Any numbers within a field are ignored after a character encountered in that field. All blanks are ignored.

Data input Page 71


The following examples would all convert to the value 51:

51"51""+51."51.0005.1E+01"51 approx" 51 read; character data ignored"51 +/- 2.21" 51 read; everything after space ignored" 51" 51 read; leading blanks ignored

The following list entries would be skipped as no data:

A51 Everything after character ignoredFifty-one No text conversion supported

Reading Fixed Length ASCII files

Fixed field ASCII files may be read if both a surface name (#X,Y,) line and a (#Fixed) line are included as the first lines in a data file. The #Fixed line consists of the start and stop character positions of each field in the surface name line (#X,Y). There must be two entries in the #Fixed line for each entry in the #X,Y line. An example:

#X,Y,Topography,Piezometric,Bedrock#Fixed,1,9,10,19,20,29,30,39,40,49

552 1026 1560 1541 1450637 2931 1610 1565 1482

1245 831 1592 1572 1502...

X would be within character position 1 to 9, Y from 10 to 19, etc. The contents of each field are processed by the same rules as comma-delimited data.

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ASCII to QSB

ASC2QSB

This keyboard command is identical to Load ASCII Table, with the exception that no surfaces are loaded into surface memory, only a binary .QSB file containing the surfaces is written.

Read ASCII Breaks

QSBL

Read ASCII Breaks allows you to read break line data (represent-ing 3D polylines) from a generic ASCII file format consisting of X, Y, Z triplets. The routine allows for free-form input files fol-lowing the same rules as Read ASCII Points (QSL). Sequential lines in the file which have three valid fields are considered adja-cent vertices on the break line. Any line in the file with more or less than three valid fields is considered the end of one break line and the beginning of the next. This format allows you to read many break lines from the same ASCII file.

Import Data -> Read ASCII Breaks

The standard AutoCAD file dialog is invoked and allowing you to specify the name for the breaks file. The default file extension for break line files is .DAT, but may be anything.

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An ASCII Break line file might look as follows:

Line 110,25,32.520,42,41.216,23,22.118,37,52.8Line 232,56,103.243,61,112.648,64,123.8Line 30.75,0.32,1.5430.64,0.27,1.3420.58,0.22,1.039

Any non-numeric character is considered a delimiter. The file shown below would load the identical break lines even though various non-numeric characters are used for delimiters.

The same ASCII Break line file as shown above, but with random non-numeric delimiters.

10 25 32.520 42 41.216 23 22.118 37 52.8

32abc56def103.243xxx61xxx112.648xyz64pqr123.8Any line without three valid numbers starts a new break line0.75,0.32,1.5430.64,0.27,1.3420.58,0.22,1.039

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This free-form format is generic enough to load most data, but be careful not to create unintended line breaks by having three valid numbers in a comment or header line.

Break line data is loaded into the results < . > surface and is rec-onciled with any breaks already present. See the Chapter 10 on break lines for more information on break line handling.

Although it is not the purpose it was designed for, you may use Read ASCII Breaks in conjunction with Breaks / Draw to draw 3D polylines from data in an ASCII file.

Read ASCII Boundaries

RBOUND

2D polyline data representing boundaries may be read from an ASCII file. When a boundary file is read, the boundary poly-gon(s) from the file become the new current boundary. The Read ASCII Boundaries command may be selected from the menu or accessed via the Set boundary command when redefining an existing boundary.

The format of the ASCII file is similar to that for ASCII break line data. Although a third field (which is the Z value in the break line format) is carried for each vertex in the boundary file. It rep-resents the bulge factor for arcs within polylines, not a Z value.

Boundary files are generally created with the Write ASCII Bound-aries command of Quicksurf. If you are manually creating an ASCII boundary file, add sequential vertices of the boundary polygon (one vertex per line), using a zero as the third field on each line. This will result in a boundary with straight lines con-necting the vertices.

The command is invoked by selecting

Import Data -> Read ASCII Boundaries

Data input Page 75


l

sis.

d z 00

You are presented with the standard AutoCAD file selection dia-log box. The default file extension is .DAT . Select the desired boundary file and it will be read, becoming the current boundary.

Boundary files may be created manually from outside data or by using the Write ASCII Boundaries command described in the exporting data section of this chapter.

Read DEM file

QSLDEM

Quicksurf can directly read USGS Digital Elevation Model (DEM) data from ASCII files. DEM data is available from the USGS and from many vendors. Two major types of DEM data sets are offered by the USGS:

3 Arc-second data

These DEM data sets originate from 1:250,000 scale maps and typically cover one degree blocks. These one degree blocks con-tain approximately 1.44 million elevation values. The x and y units are in latitude and longitude. You may use software such as Schreiber Instruments’ Projector to convert the x and y units intofeet or meters in a known coordinate system such as UniversaTransverse Mercator (UTM) or a specific State Plane prior to mapping. It is important that x, y, and z be in the same units when creating maps to be used for visualization or slope analy

7.5 minute Quadrangle data

These DEM data sets originate from 1:24,000 scale maps andtypically cover one 7.5 minute USGS quadrangle. The x, y anunits are commonly in meters. There are approximately 160,0elevation values per quad.

Page 76 Data input


Options during import

Quicksurf automatically senses the DEM type and imports either DEM format directly into surface memory. Alaskan DEM data formats are variable and may not be imported directly without reformatting.

Quicksurf allows you to optionally load DEM data directly into a surface memory grid or load the data as points and build the TIN during import. This optimized loading allows you to import DEM data in much less time and space than loading x, y, z trip-lets. A 7.5 minute quad may be loaded and ready to contour on the TIN in less than one minute on most computers.

Import Data -> Read DEM file

<Invokes standard file dialog>: select DEM fileLoad as finished Grid <No>: Yes for grid only; No for TINSurface <current>: enter new surface name

Answering Yes to the Load as finished Grid prompt loads the DEM grid nodes directly into the specified surface as a grid, with no points or TIN generated. If Configure contour is set to contour on the grid, you may immediately contour your map. The grid cell size will be that from the DEM file, being approximately 30 meters for 7.5 minute quads, and 3 arc-seconds (200 - 300 feet depending on latitude) for the 3 arc-second data sets.

Only answer Yes if you can use the native cell size as is, because Quicksurf requires point data to recalculate a grid. Loading a DEM as grid only will result in no point or TIN data, therefore you will be unable to re-grid the data set to change cell size.

Answering No to the Load as finished Grid prompt loads the DEM as points and triangulates them during import. This will allow you to recalculate an appropriate grid cell size for your needs. Selecting a smaller grid cell size will interpolate your DEM based upon the current grid method settings. Selecting a larger grid cell size will have a smoothing effect on the DEM. Choosing this

Data input Page 77


ing

ces

rge r

he -

allows you to immediately contour on the TIN (Configure con-tours set to contour on the TIN), or to re-grid the data to a differ-ent cell size (Configure contours set to contour on the Grid).

Quick projection

When loading 3 Arc-second DEM data, you have the option to use a simple projection to convert from the latitude, longitude units of the input file to x and y in units of feet or meters. This uses an equidistant-cylindrical projection with an arbitrary origin at the center of the data set. This is not intended to take the place of rigorous projection or coordinate transformation software such as Mentor Software’s Tralaine. If you are importing 3 Arc sec-ond data, you will receive an additional prompt.

Convert DEM from Lat-Long to feet/meters? <Yes>: specify

Answering Yes will perform the projection and convert x and y tothe same units as the elevation values in the DEM file, answerNo will leave the X, Y units in decimal degrees.

Because DEM models are large, you are allowed to load themdirectly into a named surface. Try to avoid moving these surfaaround within surface memory, due to their size.

DEM models are large data sets, so plan ahead. Determine whether you need to work with a TIN based or a grid based model. If you are using a grid based model, check your Configure Grid settings to confirm your options. We recommend you usevariations of the standard (continuous curvature) method for lagrid based models. This method is orders of magnitude fastethan the other grid based methods.

You may efficiently explore your large DEM data set by using tSview, Szoom and Show commands and avoiding actually drawing contours or meshes into your drawing unless needed.

Page 78 Data input


Data Export

Exporting ASCII data files

Export ASCII from memory

QSXPORT

Points, breaks or grid nodes may be exported from surface mem-ory directly to a comma-delimited ASCII file. The menu selec-tion is found under Export Data.

Export Data -> Surface data -> Write ASCII file

You are prompted for which part of the surface to export, the name of the ASCII file to be created and the surface to export. If you specify a file that already exists, you are given the choice to append the new data to the existing data or to overwrite the exist-ing file.

Points and grid nodes are written as comma-delimited x,y,z trip-lets, one point per line. Break lines are exported line by line, with each break line as a sequence of vertex x,y,z triplets, one per line. Each break line in the ASCII file is separated from the adjacent one by a blank line and a text string "Break - nn" where nn is a sequential whole number. These files may be read by the Read ASCII Breaks command to reload the saved break lines.

Export Data -> Surface data -> Write ASCII file

Points / Breaks / Grid points <default> : selectInvokes standard file dialog: Choose a file nameSurface < . >: select or press ? to pick from dialog

The requested part of the selected surface is written to the ASCII file. If the file already exists you will first be given an alert box asking if the existing file may be replaced. If you answer yes, you will receive a second prompt:

Data Export Page 79


Merge with existing data <Yes> :

Answering Yes will append the new data to the existing file. Answering No will replace the file with the new data.

Extract ASCII from drawing

DWG2TXT

This command extracts points from AutoCAD drawing entities and writes them to an ASCII file as space delimited x,y,z triplets, one per line. The points extracted from the drawing entities fol-low exactly the same rules as the Extract to surface command. The filter and auto densification options within the Configure Extract dialog box do not apply to this command. If you need those options, first use Extract to surface to create a < . > surface containing the desired data, then use Export ASCII from memory to write the ASCII file.

Export Data -> Entity XYZ data

File name: specifySelect objects: select

The selected entities will have their x,y,z nodes written to the specified file.

Write ASCII Boundaries

WBOUND

The current boundary definition (created with Set boundary) is written to an ASCII file. This boundary definition may be reloaded using the Read ASCII Boundaries command. The Write ASCII Boundaries command may be selected from the menu or accessed via the Set boundary command when redefining an existing boundary. The format of the ASCII file is completely described in the Read ASCII Boundaries description earlier in this chapter.

Page 80 Data Export


Export Data -> Boundary data

The standard AutoCAD file dialog is invoked and you should specify the name for the boundary file. The default file extension is .DAT .

Exporting 3D Studio files

Export to 3DS from memory

QS3DS

TINs, triangulated grids and grids may be written directly from surface memory to 3D Studio mesh (.3DS) files. This avoids the cumbersome process of drawing the object into AutoCAD, then DXFing it out and importing it into 3D Studio.

Export Data -> Surface data -> Write 3DS File

Surface < . >: select or press ? to pick from dialogTIN / TGRD / Grid < default > : select3DS file complete

The 3DS file representing the entire surface is written, ready to be merged into your 3D Studio scene. All meshes written from Quicksurf have the normals of all faces pointing upwards, so two-sided materials within 3D Studio are generally not needed.

The Surface region command allows you to write separate sur-face patches as different mesh objects for ease of materials appli-cation within 3D Studio.

Data Export Page 81


Surface commands

Show versus Draw

A surface will not be visible until you use specific commands which display surface geometry and their Draw or Show options to display the surface in the current viewport. In the interest of speed the Quicksurf commands of Points, Breaks, TIN, GRD, Tri-angulated Grid (TGRD), Contour and Post from memory support the ability to either Show or Draw. Draw produces AutoCAD drawing entities from a surface model, making them a permanent part of the drawing, while Show temporarily displays them in the current viewport (until the next event causing a redraw, like pan or zoom). Using Show allows you to maintain visibility of a model throughout a series of surface operations without waiting for regens or redraws. Once a model is completed it can be incor-porated into the drawing with the Draw option of the appropriate command.

Using Show is substantially faster than Draw, but remember a Shown object is not an AutoCAD entity, so it cannot be selected or manipulated with AutoCAD commands and will not be saved with the drawing file when you save the drawing.

The Quicksurf surface display command offers this prompt:

None/Show/Draw/Redraw <Show>:

You may answer with a single letter (D for Draw, etc.) or press return to Show. Responding with R or Redraw performs a redraw on the current viewport. This removes any previous Shown objects and re-displays the same prompt, allowing you to Show or Draw. The None option is supplied for use with commands such as TIN which create additional surface parts that you may not wish to display as the are made. We highly recommend using the Show option while developing your model, then use the Draw option to place the final result into the drawing.

If you are going to be using the Draw option, remember to disable any snap or object snap modes you may have set.

Page 82 Surface commands


Points

PNTS

The POINTS keyboard command of earlier ver-sions of Quicksurf has been renamed to PNTS to resolve name conflicts.

Displays the points in the current surface on screen.

PointsSurface < current >: select or press ? to pick from dialogNone/Show/Draw/Redraw/None <Show>: select

You are prompted for the surface for which to display points, with the current surface offered as the default. This is followed by the standard None/Show/Draw/Redraw prompt.

Selecting Draw will draw the points into the drawing regardless of whether or not they are visible on the screen. The points will be drawn to the current layer unless a specific layer-surface asso-ciation has been established using surface operations.

If the points extend outside the current drawing extents, you may use the Surface zoom command to reorient the view without hav-ing to draw in the points. Alternatively you may first Draw the points and then Zoom Extents to display all of them.

The Points command honors any boundary set with the Set Boundary command and only points within the current boundary are shown or drawn. Nested boundaries may be used to segregate a point set into areas of original topography and areas which have been modified during the design process.

AutoCAD point size and type settings determine how the points will appear when drawn into a drawing (PDMODE and PDSIZE). These settings do not affect the Show mode of points.

Surface commands Page 83


Breaks

BREAKS

Shows or draws the break line data from the current surface.

Breaks

Surface <current>: select or press ? to pick from dialogNone/Show/Draw/Redraw <Show>: select

Selecting Show displays the breaks of the current surface tempo-rarily in the current viewport. Selecting Draw draws the break lines from the current surface into the drawing as 3D polylines. The breaks will be drawn to the current layer unless a specific layer-surface association has been established using surface oper-ations. Both the show and draw options honor any boundaries in effect.

TIN

TIN

Generates and/or displays a triangulated irregular network (TIN) for the points and/or breaks in the current surface.

TIN


You are prompted for the surface for which to create or display the TIN, with the current surface offered as the default. This is followed by the standard None/Show/Draw/Redraw prompt. If you accept the Show default, the TIN will be created if needed and written into the current surface and displayed on the screen. The color of the displayed TIN is based upon the settings in the Surface Colors dialog box.



The TIN command honors any boundary set with the Boundary command and only triangles within the current boundary are shown or drawn. The selection criterion for a triangle being inside or outside of a boundary is set in the Configure Boundary dialog box.

As the TIN is calculated, the status bar reports triangulation and number of triangles produced. If you select Draw, rather than Show, you will receive additional prompts:

TIN

None/Show/Draw/Redraw <Show>: DLines/3dFaces/Polyfaces <P>: selectSelect invisibility...All/Interior/None <None>: select

The TIN surface may be drawn as lines, 3D faces or a polyface mesh. This command draws the complete TIN on the current layer unless a boundary is specified or the current surface has an override layer specified by the Layer surface operation.

TIN invisibility option

All or part of a drawn TIN may be made invisible. An invisible face created this way may not be seen, but will hide objects behind it when used with the hide, shade or render commands. Generally you will answer None to the invisibility prompt. This will result in a visible display.

The All selection of the invisibility options will make all triangles invisible. Invisibility is used in the special case where you want to hide contour lines in an oblique view. Normally contour 2D polylines do not hide. By superimposing an invisible TIN or grid just beneath the contour polylines, you may produce a hidden line display from an oblique view and have the contours behind a hill appear hidden.



The Interior selection of the invisibility options will make only those triangles in the interior of closed break lines invisible. Geologists use this option to make fault planes invisible, yet dis-play the structure of faulted surfaces. These invisibility options generally are used for rendering and visual presentation purposes only.

Triangulated grid

TGRD

Generates a surface model based on a triangulated grid (TGRD), using points and break lines from the specified surface. The TGRD is a triangulated model incorporating grid nodes and den-sified break lines as vertices of a complex TIN.

Triangulated Grid

Surface <current>: select or press ? to pick from dialogXXX triangles builtCreating grid points...Auto densification...XXXX triangles builtNone/Show/Draw/Redraw <Show> : select

The TIN representing the triangulated grid is calculated, then shown or drawn if requested.

Please read the concepts chapter for a complete discussion of tri-angulated grids. In brief, a TGRD consists of point data and den-sified 3D break line data which has been internally gridded based on the derivative and cell size settings of Configure Grid. The resulting grid node data, along with the break line data, form a point set which is then triangulated to form a type of triangulated irregular network termed a TGRD. This TGRD is a TIN which honors break line data exactly, but also may include curvature data when away from break lines.



A TGRD surface honors break lines exactly, but away from break lines the vertices of a TGRD are coincident with where the grid nodes would have been. The original data points are no longer vertices of the TGRD.

The TGRD command honors any boundaries specified by the Set Boundary command. The boundaries chapter explains how you may specify any desired areas of the modeled surface for triangu-lated grid generation with external and internal boundaries. Break lines made up of closed polylines can be extremely useful bound-aries in many situations. You will find that selecting closed polylines as both breaks and boundaries is a very powerful com-bination when used with TGRD, useful in volumetrics and imag-ing problems.

The options presented when selecting the Draw option for TGRD are identical to those for the TIN command, described previously.

Grid

GRD

Note the spelling differ-ence between Quicksurf ’s GRD keyboard command and AutoCAD’s GRID keyboard command.

Displays a grid model of the current surface. If a grid already exists in the current surface, this command simply displays the grid. If a grid does not exist, one is created based upon the cur-rent settings of the Configure Grid dialog box. If the standard continuous curvature method is selected, a TIN and derivatives will also be created as needed.

During a grid calculation the status bar will report progress of any required TIN, derivative and the grid calculations. The method used for grid computation will be inserted automatically in the current surface description.

Grid computations are performed only on data whose plan view lies within a defined window, which defaults to the smallest rect-angle containing all the points. The window definition is nor-mally handled automatically, but may be manually defined via the Window surface operation.



If a grid already exists in the current surface and you wish to cre-ate a new grid reflecting different cell parameters or grid meth-ods, you must first clear the old grid and derivatives parts from the current surface using Surface Operations dialog or use one of the following surface operations which clear and regenerate the grid in one step: window, cellsize, cellcount and cellfactor.

If you receive a Grid undefined error, you have the probably used surface operation Window improperly or set a cell size larger than the x,y range of your data. If the current window and your data set do not overlap, when viewed from plan view, a Grid undefined error may result. Setting the window while in a UCS will cause further confusion as the window will be set using UCS coordi-nates and your data will more than likely be in world coordinates (WCS). Please be careful to understand the differences between a UCS and WCS coordinates, see your AutoCAD manual for a detailed discussion.

The Grid command honors any boundary set with the Boundary command and only cells within the current boundary are shown or drawn. The selection criterion for a cell being inside or outside of a boundary is set in the Configure Boundary dialog box.

Grid

Surface <current> : select or press ? to pick from dialogNone/Show/Draw/Redraw <Show>:

The next prompt you get will depend on which display option you select.

Showing the grid

Grid

Surface <current> : select or press ? to pick from dialogNone/Show/Draw/Redraw <Show>: SDots/Horizontal/Vertical/Both <B>:



Selecting Dots will display the grid as an array of dots at the grid intersections. Horizontal will display the grid lines parallel to the X axis; Vertical will display those parallel to the Y axis; Both will dis-play the full orthogonal grid. Color options for displaying the grid may be set via the Surface Colors dialog. For perspective views you may want to vertically exaggerate the grid using Sur-face operations multiply (*). Showing the grid in combination with the Surface view command can create striking displays.

Drawing the grid

Grid

Surface <current> : select or press ? to pick from dialogNone/Show/Draw/Redraw <Show>: Dots/3dFaces/Polyface/Mesh <P>: select

Draws the grid in the selected form as AutoCAD drawing enti-ties, honoring any boundaries set with the Boundary command as follows:

Grid as Dots

Dots/3dFaces/Polyface/Mesh <P>: D

Draws a point at each node of the grid. Points are drawn on the current layer, unless overridden by the surface operations Layer setting. Color is BYLAYER, unless overridden by the Surface Col-ors dialog.

Grid as 3D Faces

Dots/3dFaces/Polyface/Mesh <P>: 3Invisible/Horizontal/Vertical/Both <B>:

Draws 3D faces on the grid surface with neither, horizontal, verti-cal or both edges visible as selected. Faces are drawn on the cur-rent layer, unless overridden by the surface operations Layer setting. Color is BYLAYER, unless overridden by the Surface Col-ors dialog.



Grid as Polyfaces

Dots/3dFaces/Polyface/Mesh <P>: PInvisible/Horizontal/Vertical/Both <B>: select

Draws polyfaces on the grid surface with neither, horizontal, ver-tical or both edges visible as selected. Polyfaces are drawn on the current layer, unless overridden by the surface operations Layer setting. Color is BYLAYER, unless overridden by the Surface Col-ors dialog.

Grid as Mesh

Dots/3dFaces/Polyface/Mesh <P>: MFold undefined cells <Y>? N or enter for Y

Draws the grid as a rectangular 3D polygon mesh. The mesh is drawn on the current layer, unless overridden by the surface oper-ations Layer setting. Color is BYLAYER.

AutoCAD meshes are rectangular meshes with a fixed number of rows and columns. Your surface probably is not the same shape, which results in undefined grid cells (having no z value) at some mesh edges. You have the choice of drawing the undefined cell at the Undefined cell elevation (set in the Configure Grid dialog box) or folding the cell underneath the defined part of the mesh. Selecting Yes at the Fold undefined cells prompt folds undefined cells underneath at edges, eliminating any pedestal effect.

If you want a polyface mesh pedestal surrounding your drawn mesh, use the Grid Pedestal command which is described in the utilities section of this chapter.



Contour

CONT

Generates and/or displays contours of the current surface. The basis of the contours (TIN, grid or TGRD) is controlled by the Configure Contours dialog setting. Contours are derived from a grid by linear interpolation on grid cells and from a TIN or TGRD by linear interpolation across triangles. Contours are never stored as part of a surface, but are always generated on demand from the current surface. The contour command will create a TIN, Deriva-tives, Grid or TGRD as necessary prior to displaying the con-tours. If the Contour command does generate additional surface parts, the settings of the Configure Contours dialog controls whether a TIN, Grid or TGRD is built.

The contour interval (the Z value between adjacent contours) is set via the either the Contour Interval menu command or the Con-figure Contours dialog. If the contour interval and number of intervals are set to Auto, Quicksurf will produce contours at 16 levels by default, i.e. the Z range of the TIN, TGRD or grid divided by the number of levels (16). The contour interval is dis-played on the top status bar at the completion of a show or draw of contours.

Contour colors are controlled via the Contour Colors command.

Contours are drawn on the current layer unless overridden by the surface operations Layer setting.

All shown or drawn contours honor any current boundaries. The boundary tolerance set in the Configure Boundary dialog controls how close a contour line is drawn to a boundary edge.

Contour




to

The next prompt you get depends on which display option you select.

Showing the contours

None/Show/Draw/Redraw <Show>: S

Displays the contours in the current viewport, but does not add them to the drawing.

Drawing the contours

None/Show/Draw/Redraw <Show>: DClose all <N>? select

Remember not to have object snaps set when drawing contours.

When you select the Draw option you receive an additional prompt asking whether or not to close the contours. Answering No draws each contour to the edge of the grid and stops, resulting in an open 2D polyline. Answering Yes causes each contour to be drawn across the surface, then follow the edge of the defined grid until they encounter themselves, resulting in closed 2D polylines. Any closed contours within the defined area of the grid are drawn as closed 2D polylines regardless of your answer. The

Close All option is useful when you want to Hatch or color between contours.

Closed contours may be used with AutoCAD’s Hatch command or with Quicksurf’s PFill command for screen only polyfills. WithAutoCAD Release 12’s raster image capture capability the PFill command can produce very nice displays. After running PFill, you may use the AutoCAD SELECT <ALL> command to cause thedrawing elements which may have been covered with fill colorbe re-displayed “on top” of the solid fill colors.



Contour Interval

The contour interval may be set via the Configure Contour dialog box, or directly using the Contour Interval menu command.

Contour Interval

Contour Interval/Auto <Auto>: enter value

You may enter the desired contour interval from the keyboard or pick it from the side bar menu if present. If you respond with Auto you will be prompted for the number of levels to use. The number of levels represents the number of intervals the Z range of the data points is divided into while automatically choosing a contour interval.

Surface modification

Surface modification is accomplished using the surface opera-tions commands. These are described in the surface operations chapter. The command descriptions which follow simply show how to access the surface operations sub-system.

Surface operations dialog

DSOP

Selecting the Surface operations prompt invokes the surface operations dialog box. All surface management and mathemati-cal surface operations may be performed from within this dialog.

Surface Operations

The description of all of the surface operations commands is in Chapter 8 (page 239) on Surface Operations.

Surface modification Page 93


Surface operations without dialogs

SOP

Keyboard access to surface operations is available by typing

SOP

at the Command: prompt. This allows keyword access to surface operations without invoking the dialog box. This interface is identical to Quicksurf 4.x versions. Refer to the Surface opera-tions chapter for the description of all of the surface operations commands.

Surface Options

Four commonly used surface commands are clustered for conve-nience under the Surface Options menu. All of them may be accessed via the surface operations dialog or the configuration dialogs.

Current surface

CSURF

Sets the current surface to the surface name specified. This sur-face name will be offered as the default name in any subsequent Surface: prompts.

Surface Options -> Current surface

Surface <current >: select or press ? to pick from dialog

Type a surface name or a question mark to pick the surface name from a dialog box.

Configure surface operations

Accesses the Configure Surface Operations dialog. See the next chapter, Configuring Quicksurf (page 237) , for a description.

Page 94 Surface modification


Window

Invokes the surface operations Window command which restricts where grid nodes are created. Use with caution. See page 252 for the Window command description.

Cell Size

Invokes the surface operations Cell Size command which deletes and recomputes the grid for a surface. See page 251 for the Cell Size command description.

Cell Count

Invokes the surface operations Cell Count command which deletes and recomputes the grid for a surface. See page 251 for the Cell Count command description.

Surface viewing

Quicksurf allows you to adjust your view relative to a surface in surface memory, rather than just entities drawn into your draw-ing. You may zoom based upon the extents of a given surface in memory, or automatically set up a perspective view to simulate standing on the surface at one point and looking at the surface at another. This can greatly enhance site visualization without the time and frustration of trial and error DVIEW adjustment.

The surface viewing tools can also greatly speed your work when dealing with large surfaces such as DEM topographic models. By using these surface viewing tools along with the show mode of the surface drawing commands, you can avoid placing large objects (meshes and point sets) into the drawing as drawing enti-ties. This allows you to investigate the surface from different viewpoints without waiting on regens and redraws.

Surface viewing Page 95


Surface zoom

SZOOM

Surface zoom allows you to immediately zoom so the view cov-ers an area centered over and slightly larger than the selected sur-face.

View Options -> Surface zoom

Surface <current> : select or press ? to pick from dialog

The extents of the surface will cover approximately 90% of the view. The has the same effect as drawing the surface into the drawing, then zooming extents, then zooming .9X to back off slightly. The advantage is speed: no AutoCAD entities are drawn.

Surface zoom may be executed from any viewpoint.

Surface plan view

SPLAN

Surface plan view changes to a plan view centered over the selected surface. Surface plan view is identical to surface view, but it forces the view to plan view in the current UCS prior to zooming over the surface.

View Options -> Surface plan view

Surface <current>: select or press ? to pick from dialog

The extents of the surface will cover approximately 90% of the view. The has the same effect as drawing the surface into the drawing, changing to plan view, then zooming extents, then zooming .9X to back off slightly. No AutoCAD entities are drawn.

Page 96 Surface viewing


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Surface view

SVIEW

Surface view allows you to create a perspective view simulating standing on the surface and looking at another point on the sur-face. This command should be run from plan view. The command prompts you to graphically pick a camera position and a target position for a specified surface, then it determines the 3D location of the camera and target and executes AutoCAD’s DVIEW com-mand to place you in the correct perspective view. The cameheight and lens length are set in the Configure camera dialog.

This command should be run from plan view.

View Options -> Surface view

Surface <current>: select or press ? to pick from dialogSelect viewing position: pickSelect viewing direction: pick

Select the surface to base the view upon (usually representingtopography). This surface must have a TIN, TGRD or grid present to allow Quicksurf to solve for camera and target elevtions.

When prompted for a viewing position, select the camera positusing the cursor. Quicksurf will solve for the elevation of the sface at the camera location.

When prompted for a viewing direction, a rubber-band line wilbe anchored to the camera location and attached to the cursoSelect the viewing target with the cursor. Quicksurf will solve fothe elevation of the surface at the target point. The 3D vector from the camera position (including the camera height) to the get point on the surface established the viewing direction. Thperspective view is set based upon these values and the camsettings. The surface elevations are used, so if you place the era in a valley and the target on a mountain, you will be lookinup at the mountain in the perspective view. Conversely, you mclimb the mountain and set the camera on the peak, set the tain the valley, and look down on the surrounding scene.

Surface viewing Page 97


Depending upon the complexity of your surface model, you may want to draw the TGRD or grid into the drawing as a colored mesh or polyface mesh. This lets you see the surface view with-out continually having to re-display the mesh with show. If you are experimenting with different views, it may be faster to not draw the mesh into the drawing, because you must change back to plan view each time you select new camera and target positions (forcing a regen).

Configure camera

SETCAM

The perspective view created by Surface view depends on camera and target positions as well as the height of the camera above the ground and the lens length used on the camera. Configure cam-era allows you to set camera height and lens length.

View Options -> Configure camera

Camera Configuration dialog box

Within the dialog box you are prompted for camera height and lens length.

Height above surface

The height of the camera above the surface. The default is 10. If the surface is in units of feet, this represents a camera height of ten feet above the surface. You will find that a camera height somewhat taller than a persons eye height works best. Using camera heights of hundreds or thousands produce nice perspec-tive aerial views.

Page 98 Surface viewing


Camera lens

This sets the camera lens length in mm. The default is 30 mm corresponding to a wide angle lens. Lower lens lengths corre-spond to wide angle views and higher lens lengths correspond to telephoto views. Typically lens lengths from 20 - 50 mm work well for topography.

Boundaries

Set Boundary

BOUND

You may limit the area in which Points, Breaks, TINs, TGRDs, Grids, Contours or draped objects are displayed by specifying one or more closed polylines as boundaries with the Set Bound-ary command. The boundaries may be nested. Boundaries are very useful for presentation purposes and volumetric limitations. Please refer to Chapter 9 (page 269) on boundaries for a descrip-tion of how boundaries are used in Quicksurf.

Boundary Options -> Set Boundary

Return to select all visible orSelect objects: selectShow/New/DIsable/Enable/DElete/Read/Write <DI>: select

Once selected, boundaries are independent of the polyline used to create them.

If there is no boundary in memory, you are prompted to select objects or read an ASCII boundary file. If a boundary does exist in memory you are presented the following options for creating or removing boundaries:

Show current boundaries

Show/New/DIsable/Enable/DElete/Read/Write <DI>: S

Shows the currently effective boundaries on the screen, if they are within the current drawing extents. No entities are drawn.

Boundaries Page 99


Create new boundaries

Show/New/DIsable/Enable/DElete/Read/Write <DI>: NRedefining Boundary... Return to select all visible orSelect objects: select

N points from M polylines

Select boundary entities via the normal AutoCAD object selec-tion methods. The (valid) objects selected will reported and become the currently effective set of boundaries.

Disable current boundaries

Show/New/DIsable/Enable/DElete/Read/Write <DI>: DBoundary Disabled

Disables the current boundaries, but retains them in memory. They may be toggled back on with the Enable option.

Enable current boundaries

Show/New/DIsable/Enable/DElete/Read/Write <DI>: EBoundary Enabled

Toggles on the last defined boundary set.

Delete boundary

Show/New/DIsable/Enable/DElete/Read/Write <DI>: DEBoundary Deleted

Deletes last defined boundary set from memory. Does not delete any drawing entities.

The boundary once selected can only be cleared with this com-mand. Boundary entities may be frozen or erased with no effect on the boundary once selected.

Page 100 Boundaries


A boundary tolerance is automatically calculated based upon the geometry of the boundary. This controls the edge tolerance of drawn objects (such as contours) which intersect the boundary. If you want to set this tolerance each time a new boundary is defined, you may select this option in the Configure Boundary dialog box and a tolerance prompt will appear in the Set bound-ary command.

Read ASCII Boundaries

Show/New/DIsable/Enable/DElete/Read/Write <DI>:RInvokes standard file dialog

Allows you to read an ASCII boundary file from disk. Select the boundary file to read from the file dialog box. ASCII boundary files are completely described in the Read ASCII Boundaries command section earlier in this chapter.

Write ASCII Boundaries

Show/New/DIsable/Enable/DElete/Read/Write <DI>:WInvokes standard file dialog

Allows you to write an ASCII boundary file to disk. Select the boundary file to write from the file dialog box. ASCII boundary files are completely described in the Read ASCII Boundaries command section earlier in this chapter.

Boundaries Page 101


Annotation

These commands provide annotation features for refining Quick-surf models into finished drawings. With the exception of Post from memory, these commands only operate on entities that have been drawn into the drawing, not on shown objects.

Post from memory

POST

Posts values into the drawing directly from surface memory based upon the current settings in the Configure post dialog box. This command offers the Show/Draw/Redraw option and honors the current boundary and AutoCAD Units settings. Unlike the other annotation commands, Post from memory posts values directly from surface memory, not from drawn AutoCAD entities.

Annotate -> Post from memory


The values of the points in the current surface are posted at each point in the current text style and at the text height, rotation and offset specified in the Configure Post dialog box. The number of significant digits displayed to the right of the decimal point is controlled by the setting within the AutoCAD Units command.

The posted values may be shown or drawn. If a boundary is in use, any point within the current boundary is posted, even if the resulting text slightly overlaps the boundary. Using the Show mode of posting allows fast temporary display of elevation infor-mation while editing surfaces.

Page 102 Annotation


Configure post

SETPOST

The Configure Post dialog box controls text height, rotation, jus-tification and position (offset) of posted values displayed by the Post from memory command. Selecting Configure Post from the Annotate menu invokes the following dialog box.

Configure Post Dialog box

Position

Nine preset text placements are offered in the upper left corner of the dialog box. These nine selections correspond to top left, top center, top right, center left, center, center right, bottom left, bot-tom center and bottom right. The text offset (relative to the point being posted) is a function of the text height being used. One of the nine preset positions may be selected by clicking on one of the nine boxes themselves.

The preset offsets are designed such that subsequent posting of three vertical positions, such as top right, center right and bottom right, will post in an aligned column with no overlap. The center position preset will place the decimal point of the posted value at the position of the data point. Due to this, data posted at the cen-ter position will not necessarily be aligned with other preset posted positions.

Annotation Page 103


Alternatively, you may click on the Pick offset button and graph-ically pick the offset that the posted value will have relative to the point being posted. Discrete text offsets may be entered in the X, Y, Z edit boxes if desired. Either the preset text offsets, or the user defined offsets are used, not both.

Text Height

Text height in drawing units may be entered in the Height edit box or input graphically by clicking on the Pick height button. Upon clicking on this button the dialog box temporarily disap-pears, allowing you to indicate a height by picking two points. The distance between the two points becomes the text height and you are returned to the dialog box. If you are unsure of the appro-priate text height, pick it graphically, and the height you picked will be displayed in the Height edit box. You may adjust it fur-ther in the edit box if required.

Text Rotation

The rotation angle of the posted text may be entered in the Rota-tion edit box or input graphically by clicking on the Pick rotation button. Upon clicking on this button the dialog box temporarily disappears, allowing you to indicate a rotation by picking one point which anchors a rubber-band line with which you indicate the desired rotation. The rotation angle you picked is placed into the Rotation edit box. The direction and units of the angle mea-surements are based upon the AutoCAD Units settings.

Text Justification

Text justification (left, center or right) only applies if a discrete text offset is specified. These selections are grayed out is one of the nine preset positions is selected. These settings are identical to AutoCAD text justification conventions and justify the text rel-ative to the offset point specified.

Page 104 Annotation


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Post entities

DPOST

Post entities labels selected drawing entities with their z values. This command does not operate on points in surface memory, only selected AutoCAD drawing entities, such as POINT or INSERT entities. The number of digits displayed to the right of the decimal point is controlled by the AutoCAD Units command set-tings. Trailing zeros to the right of the decimal point are not dis-played. The Post from memory command does display trailing zeros, if needed.

Post entities will annotate the Z values of most entity types, so be careful to select only the entities you want posted when using this command. By default, only POINTs, SHAPEs and INSERTed blocks can be processed.

Annotate -> Post entities

Return to select all visible orSelect objects: selectText position: selectText height: selectText angle <0>: selectAlign (Left/Center/Middle/Right) <best>: select

Select the objects to be posted via the normal AutoCAD object selection methods.

Quicksurf will choose the last selected point, and ask you to graphically position the text relative to this point using the point-ing device. The same relative offset will be used to place labels next to all other objects. Alternatively you may key in a 2D off-set, like “@.1,-.2”, which would place the text 0.1 units to the right and 0.2 units below the point.

Text height may be specified graphically with the cursor by indcating a distance from the text insertion point. A rubber-band liwill be anchored to the text insertion point. In certain cases, tis not convenient, so you may alternatively type in text height

Annotation Page 105


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drawing units) from the keyboard. This setting is over-ridden if you have set a fixed text height with the AutoCAD Style com-mand. The Post entities command works best when a variable text height is specified in the Style command. This is accom-plished by setting the text height to 0.0 in the AutoCAD Style command.

The text angle specifies the orientation of the text line. This may be specified graphically or by typing in an angle.

Quicksurf will suggest the “best” justification for text given thetext rotation angle and the position of text relative to the contrpoint. For example, if text is posted to the upper right-hand coner of a control point, it would ordinarily be best to left justify itConversely, if the text is posted to the upper left-hand corner ocontrol point, right justification would be appropriate. The avaiable justifications are left, center, middle, and right, as in the AutoCAD Text command.

Over-posting of text may occur in densely populated areas of drawing. The AutoCAD Move and Rotate commands are useful in resolving such problems.

Posting shortcut

Several utility routines supplied with Quicksurf can help you touse Post entities efficiently. Set Layer, Erase selected and Select by Z each can be helpful in layer management while posting.

Normally posting is done in conjunction with turning off or freeing unwanted layers, until just the entities to post are visible, thrunning Post entities. When posting a large number of point enties is a drawing, this procedure can be cumbersome. The Post entities command can accept an AutoCAD selection set at the Select objects: prompt. If the drawing entities to be posted all reside on the same layer, you may build a selection set of justthose entities to feed to Post entities. A handy tool to accomplish this with is Select by Z. Select by Z prompts you for a layer nameand a minimum and maximum range of entity Z values and cr

Page 106 Annotation


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ates a selection set containing all of the entities on that layer within the Z range specified. Having done this, you may run the Post entities command and answer P (for Previous selection set) at the Select objects: prompt. This will pass just the selected entities to the posting routine without having to do any layer manipulation.

When you are prompted for the text location, answer with a rela-tive position, such as @10,20 for 10 units to the right and 20 units above each point. In this way you may post large sets of drawn entities without lots of layer manipulation. Obviously a little foresight in layer management goes a long way.

Common posting problems

• Multiple values posted for each point

If you encounter multiple over-posting for each point, you haveselected more than one entity located at the same X, Y locatioThis commonly happens if you have drawn points into the draing for more than one surface or have co-located points and wsymbols or survey symbols. Turn off all layers except the poinset you wish to post and try again.

• Text height irregularities

If the text height appears incorrect or the aspect of the text sestrange, you probably are using a text style with a fixed, rathethan variable, text height. Use the AutoCAD Style command set the text height to 0.0 (variable) and try again.

Annotation Page 107


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• Incorrect number of significant digits displayed

The number of units displayed to the right of the decimal poinfor posted values is based upon the settings in the AutoCAD Units command. Use the Units command to set the appropriate preci-sion and try again. Trailing zeros to the right of the decimal poare dropped.

• Text rotation angle are not as expected

The rotation angle is affected by the angle measurement settiwithin the Units command and any Snap settings. Verify those settings and turn off snaps modes and try again.

• Posted values are not uniformly located relative to the poi

Objects snaps and snap modes can cause the posted values snapped to unrelated drawing entities. Turn off all snaps priorusing Post entities.

Smooth Contours

SMOO

Applies a smoothing algorithm to contour polylines and drapeobjects. This may improve the appearance of a contours geneated using a sparse grid. Smoothing contours greatly increasfile size, so use only where required. If you wish to smooth thsurface itself, rather than just the resulting contours, consider Moving Average command described in the Utilities chapter.

Annotate -> Smooth Contours


Page 108 Annotation


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Select objects to be smoothed via the normal AutoCAD object selection methods. Any entity in a drawing may be selected for smoothing, but only smoothable polylines will actually be pro-cessed; other entities will be ignored. This command utilizes the spline fitting of the AutoCAD Pedit command.

Smoothing variables

The smoothing technique may be controlled by setting two Quicksurf AutoLISP variables, howsmooth and splinesegs.

Howsmooth controls the type of smoothing applied to the contour polylines. Set “howsmooth” to:

“d” to decurve “f” to fit“s” to spline (default)

Splinesegs controls the number of spline segments created foreach segment in the un-smoothed polyline. By default this is to 8, causing eight segments for each original segment. This causes the file size to greatly increase when large sets of contourare smoothed. Smooth contours only if needed and consider lering the setting of splinesegs. Set splinesegs to a numerical value to be used when splining polylines. Setting this to -1 results in arc approximation for segments.

Example:

Command: (setq howsmooth “s” splinesegs -1)

will select splining with the arc approximation.

Annotation Page 109


Index Contours

INDEX

Highlights major contours by widening them and/or moving them to another drawing layer. Those contours lying at integer multi-ples of the index interval are changed to the selected width and layer.

Annotate -> Index Contours

Index interval <>: enter valueIndex layer <unchanged>: layer name, or enter for current layerIndex width <default>: value or rubberband line

At the interval prompt, enter a value as the index interval. For example, entering 200 will highlight the 0, 200, 400, 600, etc. contours.

At the layer prompt, enter a new or existing layer on which to place the indexed contours.

At the width prompt, enter the desired index polyline width in drawing units or specify a width graphically by using the rubber-band line attached to the cursor.

Label contours

LABEL

Labels contour lines with their z values at user-selected locations.

Annotate -> Label Contours

Label location: select pointsText height <default>: value, or enter for default, or rubber-band line

When prompted for contour label locations, select label locations (on drawn contour lines) with the cursor, ending with an enter when done.

Page 110 Annotation


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Select text height by indicating with the cursor and rubber-band line or by typing a numeric value for text height in drawing units.

Avoid transparent zooms when using the Label Con-tours command.

Each label point will be marked with a small circle as it is selected. After the text height is selected, each circle will disap-pear; a gap will appear in the appropriate contour line; and a label will appear in the gap. Each label will have the same layer, color and elevation attributes as its contour line. The label will be drawn in the current text style and rotated parallel to the contour.

Label placement should be planned carefully for best aesthetic results. Overlaps and other minor placement errors may be cor-rected with the AutoCAD Move and Rotate commands. The Undo command may be used to undo more serious errors pro-vided Undo was enabled before labeling.

Common contour labeling problems

If Label contours is not prompting you for text height, you may have a fixed text (rather than variable) height set in your AutoCAD Style command. Running the Style command and set-ting text height to 0.0 (variable) will bring back the text height prompt.

If label placement is irregular, you may have object snap set to snap to a particular entity element. Set object snap mode to None to correct the problem.

The label command relies on the z value of the contour polyline to determine the elevation. Many AutoCAD editing commands can change the elevation of a contour (move, stretch, pedit, etc.). If you edit a contour polyline, then subsequently label it, you may get a different value than the original elevation.

If you have a very small text height set and pick a label location such that the text doesn’t intersect the contour, in very rare cathe contour polyline will disappear. If this occurs, use the Undo command to recover the contour and re-pick the label location

Annotation Page 111


Auto-Label Contours

MLABEL

Labels contour lines with their z values at automatically selected locations based on a guide polyline indicating general label place-ment. All visible contours (2D polylines) which are crossed by the guide polyline are labeled at their intersection with the guide polyline.

Draw a guide polyline crossing the existing drawn contours. The intersection of this polyline and the contour polylines represent potential label locations. Freeze or turn off layers with unrelated 2D polylines which are crossed by the guide polyline.

Annotate -> Auto-Label Contours

Label interval: enter z intervalText height <default>: value, or enter for default, or rubber-band lineSelect guide polyline: select polyline

Select a Label interval representing the Z interval for labelling. Only those contours at even multiples of the Label interval are labeled. For example, with contours drawn at 10 unit contour intervals, selecting a Label interval of 50 would label the 50, 100, 150,... contours.

Select text height by indicating with the cursor and rubber-band line or by typing a numeric value for text height in drawing units.

Each label will have the same layer, color and elevation attributes as its contour line. The label will be drawn in the current text style and rotated parallel to the contour.

The Auto-Label Contours command is identical to the Label Con-tours command except for location determination. The 3D polylines generated by 3D Flowlines make good guide polylines.

Page 112 Annotation


Hachure contours

TICK

Draws evenly spaced, locally perpendicular tick marks (hachur-ing) on selected polylines.

Annotate -> Hachure Contours

Select objects: select contour polylinesUpward/Center/Downward <D>: selectDistance between ticks <default>: numeric value, or rubber-band lineLength of ticks <default>: numeric value, or rubber-band line

At the first prompt, select the polylines to be hachured with the standard AutoCAD object selection methods, ending with enter.

At the next prompt, select whether the tick marks should extend downward (D), upward (U), or be centered (C) on the polylines. For most purposes, ticks are applied downward and only on the closed contours of a depression. The centered option is useful for quickly constructing cross section orientations in highway design or building a quick railroad symbol.

If a selected polyline is a 2D polyline (as are all Quicksurf-gener-ated contours), the ticks are drawn at the elevation of the polyline. If it is a 3D polyline, the ticks are drawn at the current elevation setting on the assumption that they will be moved to the correct elevation later using the Drape command.

Annotation Page 113


Color control

Surface colors

PAINT

Quicksurf objects representing surfaces (TIN, TGRD or Grid) may be colored based on surface properties such as elevation, slope, visibility, lighting or by the elevation of a second surface. The Surface colors dialog box controls all aspects of surface col-oration. Both the show and draw options support these color options, with the exception that some AutoCAD entities such as meshes and polylines, can only be displayed in a single color.

The Surface color dialog settings only affect surfaces which are subsequently displayed, it does not change surfaces which have previously displayed. These settings control all surface colora-tion for the remainder of the drawing session unless changed by you or another configuration is read using Read Configuration.

If surface coloration is set to None, the draw option produces entities with color BYLAYER and the show option displays in the current color of the Set show color command.

The following entities can be drawn by Quicksurf and support surface color options:

Surface representation AutoCAD entity

GRID Dots option PointTIN, TGRD Line option LineTIN, TGRD, GRID Pface option PFace meshTIN, TGRD, GRID 3D Face option 3D Faces

These entities are drawn by Quicksurf only in the current color:

POINTS PointBREAKS 3D polylineGRID Mesh option Mesh

Page 114 Color control


ch

When a surface color option is selected, each element of the TIN, TGRD or Grid is evaluated and a color is assigned to that ele-ment. The coarseness or fineness of the coloration is dependent upon the geometry of the object being colored. For TGRD and Grid representations, coarseness is a function of the grid cell size used when the surface was created.

The colors of a surface will be a function of the method, the range of values in the surface, the number of colors and the color sequence used. These are all accessed from the Surface Colors dialog box.

Surface Colors dialog box

The Surface Colors dialog box allows you to pick a coloration method from the choices down the left side of the box. The other options in the box are enabled or disabled depending on your choice. After selecting a method, you may configure the color sequence by selecting the Configure Colors button.

Method

You may color a surface based upon its Elevation, Slope in degrees, Slope in percent, Light, Shadow, Visibility, Direction, by Another surface’s Z value, or use no special coloration. Eaoption is described individually:

Color control Page 115


Z Elevation

The surface is colored based upon its Z value. The specific ele-vation versus color is controlled by the Configure Colors dialog.

Slope (Degrees)

The surface is colored based upon its slope in units of degrees. The specific slope versus color sequence is controlled by the Configure Colors dialog.

Slope (Percent)

The surface is colored based upon its slope in units of percent. Whether 100% slope is represented as 100. or 1.00 is dependent upon your Configure Units setting for percentage. (This refers to the Quicksurf dialog, not the AutoCAD Units command.) The specific slope versus color sequence is controlled by the Config-ure Colors dialog.

Light

Surface areas are colored based upon how they would be illumi-nated by a single light source. The surface is colored based upon the angle of incidence of the light falling on the surface. You must specify both a light source location and a target location to use this option. Doing so establishes a direction vector for the light. All light rays are considered to be parallel to this direction vector.

Pressing the Pick Source button allows you to graphically pick the X,Y location of the light source. The current elevation is used for the Z value. Alternatively, you may enter or edit the X,Y,Z coordinates of the light source in the edit boxes.



Pressing the Pick Target button allows you to graphically pick the X,Y location of the target. The current elevation is used for the Z value. Alternatively, you may enter or edit the X,Y,Z coor-dinates of the light target in the edit boxes.

The illuminated parts of the surface are colored based upon the angle of incidence and the specific angle versus color sequence specified in the Configure Colors dialog. The color of each face (triangle or grid cell) is based upon the angle between the light ray and that face or grid cell. Zero degrees represents lighting parallel to the face and ninety degrees represents light falling nor-mal (perpendicular) to the face. Only illuminated areas of a sur-face are shown or drawn. Areas of a surface in shadow or illuminated from below are not colored.

For natural lighting studies you may select the Locate Sun but-ton (described below) to automatically set the Source and Target locations based upon a date, time and site latitude.

Shadow

The shadow option is the inverse to the Light option. Only sur-face areas in shadow are colored based upon a specific light source and target. The surface is colored based upon the angle of incidence of the light direction and the surface. The coloration indicated how deeply shadowed various areas of the surface are. You must specify both a light source location and a target location to use this option. Doing so establishes a direction vector for the light. All light rays are considered to be parallel to this direction vector.

Pressing the Pick Source button allows you to graphically pick the X,Y location of the light source. The current elevation is used for the Z value. Alternatively, you may enter or edit the X,Y,Z coordinates of the light source in the edit boxes.



Pressing the Pick Target button allows you to graphically pick the X,Y location of the target. The current elevation is used for the Z value. Alternatively, you may enter or edit the X,Y,Z coor-dinates of the light target in the edit boxes.

The shadowed parts of the surface are colored based upon the angle of incidence and the specific angle versus color sequence specified in the Configure Colors dialog. The color of each face (triangle or grid cell) is based upon the angle between the light ray and that face or grid cell. Zero degrees represents a face par-allel to the light direction and ninety degrees represents a face pointing directly away from the light source. Only shadowed areas of a surface are shown or drawn. Areas of a surface illumi-nated by the light are not shown or drawn.

For natural lighting studies you may select the Locate Sun but-ton (described below) to automatically set the Source and Target locations based upon a date, time and site latitude.

Locate Sun

Both the Light and Shadow options require selecting a light source and target location to establish a direction vector for the lighting. The Locate Sun option establishes this vector automati-cally given the date, time and latitude of the model. Both the source and target locations are filled in automatically to reflect the correct position of the sun. The actual x, y, z coordinates in the source and target boxes may not appear to relate to your model, but the direction vector they establish will properly repre-sent the sunlight direction for the time, date and latitude you specify. Pressing the Locate Sun button invokes the following dialog box.



Locate Sun dialog box

Specify the date by placing the day in the day edit box, selecting the month from the pull-down list and specifying the year in the year edit box.

Specify the time in decimal hours (0.0 to 24.0) and select AM or PM. You may specify time as military time (i.e. 15.00 for 3 PM) if desired and it will be converted to a twelve hour basis and the PM button will be activated if appropriate.

Specify the latitude of your site in decimal degrees. A latitude of -90.0 degrees represents the south pole, zero is the equator and +90.0 represents the north pole.

Visibility

The visibility option allows you to specify a view point location and color the surface based upon what is visible from that point. The view point location is specified pressing the Pick Source button or filling in the X,Y,Z coordinates of the view point above the surface in the source edit boxes. The surface is colored based upon the angle from this view point to any given surface face or cell. Make sure that your view point is at an elevation higher than the surface. The visibility sight lines are radial from the view point, not parallel. This is quite different than the light or shadow option.



The view point of this Visi-bility option is not the same as the AutoCAD VPOINT viewpoint.

Areas of the current surface visible from the selected viewpoint will be colored based on the viewing angle in degrees along with the settings in the Configure Color dialog box. Invisible areas or areas seen from beneath will not be shown or drawn. The color of each face (triangle or grid cell) is based upon the angle between the sight line and that face or grid cell. Zero degrees represents a face parallel to the sight line (edge on) and ninety degrees represents a face or grid cell pointing directly at the viewer.

Direction

The Direction option colors a each triangle or grid cell of a sur-face based upon its aspect (the direction in which it faces). The number of colors selected in the Configure Colors dialog box determines into how many groups the 360 degrees of the compass are divided. All of the faces or grid cells of the surface are sorted into these color groups based upon the direction they are facing. Direction is measured counterclockwise from the positive x axis. The transition from 360 to 0 degrees always produces a disconti-nuity.

For example, if you chose only four colors in the Configure Col-ors dialog box, then used the Direction option, the surface would be displayed in four colors, representing those faces pointing between west and north in first color, north to east in the second color, east to south in the third color and south to west in the fourth color. Selecting 36 colors would divide the compass into ten degree increments and color faces based upon those 36 classes.

Another Surface

You may color one surface based upon the Z value of a different surface. The specific elevation versus color relationship is con-trolled by the Configure Colors dialog. This powerful feature allows you to display the geometry of one surface colored by the z value of a different surface. The geometry of the displayed



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model is based upon the current surface and the coloration is based upon the Z value of the surface specified in the Surface edit box. This "other" surface must contain either a TIN, TGRD, or grid; it may not contain just points or the needed elevation infor-mation will not be available.

This option is useful in displaying concentration data related to structure, depth or thickness information. Problems of displaying ore grade, contaminant concentration, fluid saturation, or geo-physical measurements as they relate to zone thickness or struc-ture are quite common. The Another Surface option lets you easily build striking visual displays of these situations.

None

Selecting the None option disables all surface coloration options. TIN, TGRD or Grid displays will be in a single color. The color used will be BYLAYER (i.e. in the color assigned to the current layer) for the Draw option. Using the Show option, the color will be as specified by the Set Show Color menu selection.

Drawing Legend Checkbox

Selecting the Drawing legend checkbox will show or draw an annotated legend with the color sequence and the numeric range of each color. Upon showing or drawing a TIN, TGRD or grid with a Surface Color option in effect, you will be prompted to pick a rectangular window in which to place the color legend. Graphically pick a window and the legend will be displayed. If you have elected to display a legend, then decide in the middle of the command that you don’t want it, you may respond with a ctrol-C to abort the legend display when prompted for the windo

If the Drawing legend checkbox is checked, you will be promptefor legend placement every time you display a TIN, TGRD or Grid. You will probably want to disable the drawing legend display during your design process, when you are repeatedly displaying surfaces.



Configure Colors Button

The Configure Colors button invokes the Surface Color Sequence dialog box (described below) which enables you to control which colors are used and their sequence.

Surface Color Sequence

The sequence of colors used by all of the Surface Colors options is controlled by the Surface Color Sequence dialog box. This dialog is invoked by pressing the Configure Colors button within the Surface Colors dialog box.

Surface Color Sequence dialog box

The Surface Color Sequence dialog allows you to control the col-ors and their display sequence relative to the property (elevation, slope, etc.) being used to color a surface. Every color sequence starts at a Starting Color, and increments color-by-color for the specified Number of Colors. For example, if you are breaking the range of Z elevations in a surface into ten equal intervals the Number of Colors would be 10. If you chose 20 as the Starting



Color, the lowest interval would be displayed in color 20, the next in color 21, the next in color 22, etc. through color 29. In this way you may use any contiguous part of the 256 color range for your interval color sequence.

The standard AutoCAD color sequence is not very useful for most mapping applications as is, so Quicksurf allows you to rede-fine the color sequence in any order to suit your needs. By press-ing the Setup Remapped Colors button, you may design custom color sequences to match your display needs. Several standard color remapping files are included with Quicksurf.

The resulting color sequence and values for each color are shown in the sample surface color legend on the right side of the dialog box. This display changes dynamically as you adjust your color settings.

You may limit the range of values to be colored by selecting the Use Range checkbox. Only those areas of the surface existing between the specified minimum and maximum values will be dis-played.

Pressing the Set Interval button invokes a dialog allowing you to specify specific ranges (elevation, slope, angle of incidence) for each color. These intervals need not be regularly spaced and may contain gaps. A Blank Color is defined for use in any gaps.

Each parameter is individually described starting on the next page.



Starting Color

The starting (lowest) color number used in a color number sequence.

Number of Colors

The number of colors in a color sequence. Nice results may be obtained with between 10 and 50 colors. The color number sequence will start at the Starting Color value and continue for the Number of Colors. If you specify a value greater than 255, the color sequence will repeat after reaching color 255.

The range of values in the surface being displayed is divided into the same number of intervals as you have Number of Colors. This range may be different for a TIN, TGRD and Grid of the same surface, due to the curvature inherent in TGRD and grid models. To insure that the color breaks occur at the same points on the dif-ferent surface displays, you may use the Use Range setting and specify a minimum and maximum value. The difference between the specified minimum and maximum values are divided into the number of intervals specified by the Number of Colors value.

Blank Color

The color used for gaps in defined intervals when using the Set Intervals option.

Use Range

When the Use Range checkbox is marked, only those areas of the surface existing between the specified minimum and maximum values will be displayed. The range between the Minimum and Maximum values is used together with the Number of Colors to determine interval colors. Ranges may be used either to clip the data being displayed or to force breaks between color intervals to occur at specific values (see example below).



Maximum value

Values above this are displayed in the same high color, being the next higher one in the color sequence. The value is in the units of the property being used for coloring (elevation, slope in degrees, slope in percent, angle of incidence in degrees, etc.).

Minimum value

Values below this are displayed in the same low color, being the next lower one in the color sequence. The value is in the units of the property being used for coloring (elevation, slope in degrees, slope in percent, angle of incidence in degrees, etc.).

For example, if you are using color by elevation and your data ranges from 8 to 91 meters in elevation, not specifying a range will give you odd color intervals. If you wanted to have twenty color intervals, each representing five meters, you would select the Use Range checkbox; set a Minimum of 0.0; set a Maximum of 100.0; and set Number of Colors to 20. This would result in the Starting Color for 0 - 5 meters, the next color for 5 - 10 meters and so on. The resulting surface color legend is previewed on the right side of the dialog box.

Low color and high color are next colors below and above color range being used. If your color sequence starts at color 1, the low color will be 255.

For this same data set if you selected Use Range; Minimum of 20.0; Maximum of 80.0; and Number of Colors of 6, all values below 20.0 would be shown in the low color; all values greater than 80.0 would be shown in the high color; values from 20 to 30 would be in the starting color; 30 to 40 in the next color; and so on.

Set Interval

Pressing the Set Interval button invokes an interval definition dialog box. The intervals are automatically filled in based upon the settings of Starting Color, Number of Colors and any range settings as well as the maximum and minimum values of the cur-rent surface or the Use Range settings. Generally you will want



to specify maximum and minimum values in Use Range box prior to selecting Set Intervals. By doing so you may force the breaks between adjacent color intervals to be at round numbers. You may subsequently change any of the interval settings manu-ally.

The range of the property (elevation, slope, etc.) being colored is divided by the Number of Colors to establish the high and low value for each color interval. If the Use Range checkbox is selected, the user-specified maximum and minimum values are used, rather than the actual data extremes. The user may force breaks between adjacent color intervals to occur at round num-bers.

Surface Color Intervals dialog box

The Surface Color Intervals dialog box is automatically filled in based on these values. The number of intervals is determined by the Number of Colors chosen in the Configure Colors dialog. You may change the numeric high and low values in the edit boxes to represent any range you wish for each color. If you leave a gap in the numeric values between adjacent color intervals they will be colored in the Blank Color. Two extra color intervals are defined:



high color for all values above the highest defined interval and low color for all values below the lowest defined interval. These are the next color above and below the color sequence being used respectively.

The key to effective use of intervals is based on setting the Num-ber of Colors and a Maximum and Minimum in the Use Range box in the Configure Colors dialog prior to pressing the Set Intervals button. This allows Quicksurf to intelligently fill in the intervals for you and reduce your time spent editing interval definitions.

Remap Colors

DCMAP

Invokes a dialog box which allows you to interactively re-map AutoCAD colors into a different color number sequence. Gener-ally this is accessed via the Setup Remapped Colors button of the Surface Colors dialog box.

Remap Colors dialog box



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Using Remap Colors

The Remap Colors dialog box is separated into two large color maps. The upper map represents the standard AutoCAD color sequence for your display configuration. The lower map repre-sents the re-mapped colors. Each map displays color #1 in the upper left corner. The color numbers increase from left to right across each row and continue on the left side of the next row.

A current color may be selected by clicking on any desired color in the upper color map. The Current Color box between the two maps will change color to reflect your pick. Picking any color square in the lower color map will redefine that color to the cur-rent color. The lower map will change as you set colors by click-ing on them. By selecting the desired color from the top map, then clicking on the bottom map, you may quickly construct a color sequence that fits your needs. This color map may be used with all of the Surface Color options.

Re-mapped colors may be saved to or read from an ASCII text file using the Save and Load buttons. These buttons invoke the standard file dialog to write or read a color mapping file. The default file extension for a color mapping file is .CLS. A Reset button allows resetting to AutoCAD’s default color sequence.

A color map is simply an ASCII file with the filename extensio.CLS containing the desired color sequence. Although it is mueasier to create a color mapping file with the Remap Colors com-mand, you may create one with a text editor if needed. The ficonsists AutoCAD color numbers, one number per line. The finumber in this file will substitute for color #1, the second for #and so on.



Set SHOW Color

Selects the color assignment method used when points, TIN, grid or contours are shown on screen with the Show option when no Surface Color options are in effect.

Set Show Color

XOR/Inv/Color number <XOR>: select

XOR Option

The XOR (exclusive-or) option causes objects displayed with the Show option to appear on screen in the color which is the inverse of the background color. Showing in XOR mode a second time will restore the screen to its original appearance.For example: Starting from a blank screen with XOR enabled (the default condition), show the grid of a surface. Next show the con-tours without redrawing; the contours will appear over the grid. Now show the contours again; they will be removed from the screen leaving the grid in place, whereas a Redraw would have removed both contours and grid.

Invisible Option

The Invisible option causes objects to be shown in the background color, which in effect shows nothing on a blank screen. This option is for use in displaying on top of color-filled screen areas such as are produced with the Pfill command. If there are color-filled areas, the shown objects will be visible only in those areas.

Color Number Option

This option simply causes objects to be shown in the designated color number. Answer the prompt with the desired AutoCAD color number (e.g. 1, 2, 35, etc.).



Contour colors

Contours may be colored with one of three methods.

Color options -> Contour colors

Color Contours <N>: Y for color contoursColor contour method:Cycle/Interval/Split <I>: select

If you respond Yes for color contours, you are prompted for the method for contour coloring. The next prompt will depend on which you choose:

Cycle Option

Causes contour colors to cycle repeatedly through a sequence of colors.

Cycle/Interval/Split <I>: CStarting color <1>: valueNumber of colors to be used <6>: value

At the starting color prompt, set the color for the lowest contour on the drawing. At the number of colors prompt, set the number of colors to use. Contours will be assigned this sequence of colors in order of ascending z value. This option may be used together with remapped colors to provide any desired contour color sequence. If you are operating your monitor in a 256 color mode, load the STDQS color remapping file and set a Starting color of 1 and Number of colors to 20. This will yield a smoothly graduated color range on most graphics cards. Refer to the Configure Colors section in this chapter how to load a color remapping file.

Interval Option

Causes every Nth contour to be highlighted.

Cycle/Interval/Split <I>: IBase color for contours <5>: valueHighlighted color contours <1>: valueInterval for highlighted contour <5>: value



At the Base color prompt, set the color for non-highlighted con-tours. At the Highlighted color prompt, set the color for highlighted contours. At the interval prompt, set the interval for highlighting. The response shown above would display blue (5) contours with every fifth contour in red (1). Note that the example interval (5) highlights every fifth contour, not an interval of five feet or meters.

Split Option

Causes each contour to be assigned one of two colors: one for those below and one for those above a specified elevation.

Cycle/Interval/Split <I>: SLow color for contours <5>: valueHigh color for contours <1>: valueElevation for color split <450.0>: value

At the Low color prompt, set the color number for lower eleva-tions; at the High color prompt, set the color number for higher ele-vations. At the elevation prompt, set the elevation at which the colors are to split. If a contour falls exactly on the split elevation, it is displayed in the low color. If the split elevation is above the highest or below the lowest elevation all the contours will be dis-played in one color.

Screen fill

PFILL

Colors a closed polygon with the selected AutoCAD color in the same manner as AutoCAD’s Hatch command. This is a screen paint operation only, and a Redraw will remove the color.

Pfill

Return to select all visible orSelect objects: select closed polylines



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This command does not produce a fill which may be plotted. It may be captured in a raster format with AutoCAD’s Saveimg command. Entities which have been covered by Pfill may be dis-played on top of the solid fill by using the AutoCAD Select com-mand and selecting the entities by crossing or window. The Select command highlights, then redraws the selected entitiescausing them to be displayed on top of the screen fill.



Volumetrics

Volumes may be computed directly from surfaces residing in sur-face memory using the Surface volume, Area volume or Bound-ary volume command or computed from a drawn TIN, TGRD or Grid using the Volume by entity command. None of these volume functions use the current boundary which may have been set with the Set Boundary command, rather they prompt for closed polylines representing areas under which to calculate volumes if areas are required. Please refer to the chapter on volumetrics for a complete discussion on calculating volumes.

The three commands which calculate surfaces directly from memory (Surface volume, Area volume and Boundary volume) all invoke the same dialog box.

Surface Volume dialog box

Volume calculation

Volume may be calculated between a surface and the zero plane (i.e. sea-level), between a surface and a constant elevation, or between two surfaces. If the volume requested is between two surfaces or between a surface and a constant, the results surface <.> will contain the actual thickness surface for which the volume is calculated. You may show or draw this surface to confirm its

Volumetrics Page 133


geometry. Always inspect the thickness surface prior to volume calculation by showing the TIN, TGRD or Grid from an oblique viewpoint or by contouring it. In some cases the edges may con-tain anomalies; either correct the surface or exclude the edge effect by using Area Volumes.

Within the dialog box you must specify the basis for the volume (Planar TIN, TIN with derivatives, Grid or TGRD), the first sur-face, optionally a second surface or constant, and output file type.

Basis for volume calculation

Planar TIN Calculate volumes based on the planar TIN.TIN w/ Deriv Calculate volumes using the TIN and derivatives.Grid Calculate volumes based on the Grid.TGRD Calculate volumes based on the TGRD.

The volume will be computed on the selected surface part. If a part (Grid or TGRD) does not exist, the selection will be unavail-able. If the surface only contains points, then a TIN will be cre-ated as needed. When in doubt, choose Planar TIN.

First surface name

Select the surface under which to calculate volumes from the sur-face pick list. If this surface represents thickness, the volume should be computed between this surface and the zero (XY) plane. If the volume to be computed lies between two surfaces or between one surface and a constant elevation you will need to specify the second surface or constant.

Second surface name

If the desired volume is between two surfaces, click on the check box next to the surface pick list and select the second surface from the pick list. A new surface representing the difference

Page 134 Volumetrics


between the two surfaces (first surface minus second surface) is computed and placed in the results <.> surface and the volume is calculated.

Internally this computation uses the TIN, derivatives, grid and/or TGRD with the Maximize option within the surface operation subtract. The points of each surface are draped onto the other internally, so a thickness may then be computed. This insures the most rigorous resulting thickness surface. When calculating the volume between two surfaces, curvature is used for the internal drape only if the TIN with derivatives option is used and Deriva-tives is set to 2nd in the Configure Grid dialog box.

Two surface example

If you have two surfaces, EXISTING and PROPOSED, and select PROPOSED as the first surface and EXISTING as the second sur-face, the results <.> surface will contain your cut/fill surface. Positive areas represent fill areas (P - E > 0) and positive volumes represent the fill volumes. Negative areas represent cut areas (P - E < 0) and "negative" volumes represent the cut volumes. Posi-tive and negative volumes represent the volumes above and below (respectively) the zero (XY) plane of the surface being computed. The net volume reported is the sum of positive and negative volumes. When the net volume equals zero, the cut and fill volumes are the same.

Constant

If the desired volume is between a surface and a plane of constant elevation, select the check box next to the Constant selection and enter the constant value in the edit box. A surface representing the difference between the first surface and the constant (first sur-face minus constant) is computed and placed in the results <.> surface and the volume is calculated.

This option is convenient for determining reservoir volumes at different water levels.



None

The volume between the first surface and the zero plane is com-puted. Select the check box next to None. Use this for comput-ing the volume of a surface already representing thickness.

File output

The resulting volumes are always displayed on the text screen, but may be optionally written to a text file. Select the check box of the desired option and press the File button and supply a file name up to eight characters in file dialog. The appropriate file type (.txt) will be appended.

ASCII Writes an ASCII text file.None Does not write a file.

If a volume units conversion factor and units name has been spec-ified in the Configure Units dialog, the volumes will be converted and displayed in the specified units. Specify the file name using the standard file dialog.

Label areas

Area volume and Boundary volume allow for the volumes within multiple sub-areas of the surface to be calculated. When multiple area polygons are selected, selecting the Label Areas checkbox will cause each polygon to be sequentially labeled with area num-bers. These area numbers correspond to the area numbering in the volume report. The labels are placed on the current layer, in the current text style, and at a text height equal to the grid cell size, unless overridden by a current text style containing a fixed text height.



Running a volume command

After selecting the options in the Surface Volume dialog box and pressing OK, you are prompted to select area polygons (if needed) and the calculated volumes are displayed on the text screen. The volume results are written to a file or database table if requested.

At least a TIN is required for volume calculation. If there are only points in a surface used in a volume calculation, the surface parts needed for volume calculation will be automatically created. The specific methodology used in volume calculation is described in the volumetrics chapter.

Volumes reported

The volume report produced looks similar to the following:

VOLUMES: Reported in Cu.Yds.Using 0.37037 cubic units/Cu.Yds.

Area Positive Volume Negative Volume Net Volume1 15025.1 14215.5 809.62 10215.3 9812.4 402.93 982.5 3402.5 -2420.0

Total 26222.9 27430.4 -1207.5

For each area three numbers are reported:

Positive Volume: The positive volume within the area polygon.Negative Volume: The negative volume within the area polygon.Net Volume: The net sum of volumes within the area polygon.

A Total Positive Volume is reported representing the total positive volume of the entire surface. A Total Negative Volume is reported representing the total negative volume for the entire sur-



face. Positive volumes represent areas with Z values greater than zero and negative volumes represent areas with Z values less than zero.

If you have selected a volume conversion factor and unit name in the Configure Units dialog box, the volumes reported will have the conversion factor applied and the units name will be dis-played.

The three variations of the volume command are individually described below.

Surface volume

SVOL

The Surface volume command calculates the volume under an entire surface in surface memory. If you are using this volume to compare to a volume computed under a different surface, you must insure that the area covered by the two surfaces are identi-cal.

Volumetrics -> Surface volume

The Total Volume reported represents the volume under the entire surface.



Area volume

AVOL

The Area volume command calculates the volume under one or more sub-areas of surface in surface memory. Each sub-area is defined by selecting a closed polyline representing the area under which the volume is to be calculated. You may select as many sub-areas as you wish.

Caution: Area polygons should not overlap!

Be careful not to overlap or nest area polygons, or incorrect results will be obtained. If your area polygons are adjacent to one another use OSNAP when constructing the polylines to insure that adjacent area polygons share vertices.

Volumes may be calculated between a surface and the zero plane (i.e. sea-level), between a surface and a constant elevation, or between two surfaces. If the volume requested is between two surfaces or between a surface and a constant, the results surface <.> will contain the actual surface for which the volume is calcu-lated. You may show or draw this surface to confirm its geome-try.

The volume of each area will be calculated and reported in either an ASCII file or a database table as specified in the dialog box.

Volumetrics -> Area Volume

If a selected area polygon does not entirely overlie the surface being calculated, the volume reported is just for the portion of the surface which underlies the polygon.



Boundary volume

BVOL

Boundary volume is a special case of Area Volume where the thickness surface being calculated tapers to zero and the specific "zero-line" polyline must be honored, even if it crosses TIN or Grid boundaries. This command should not be used for general volume calculation: use Area volume instead.

Boundary volumes was designed for petroleum industry calcula-tion of "hydrocarbon pore volume" maps. In these situations a negotiated zero-line representing the absolute zero edge of the hydrocarbon accumulation is determined and must be honored exactly by all volume calculation. The zero-line polygon should be drawn at an elevation of zero. The Z value of the surface being calculated is forced to zero everywhere along this zero line. This is quite different from the polygon area boundaries which honor the Z value of the surface.

Volumetrics -> Boundary volume

This command is for special cases such as stockpile volumes where the toe of the pile is known exactly, or other volume prob-lems where the surface being calculated tapers to a known zero edge. For general volume problems, use the Area Volume com-mand instead.



Volume by entity

VOLUME

Volume by entity calculates the volume under AutoCAD drawing entities. Unlike Surface volume, Area volume and Boundary vol-ume which operate on surfaces in memory, Volume by entity only operates on drawing entities such as meshes, polyface meshes and 3D faces drawn with the TIN, TGRD or Grid commands.

Volumetrics -> Volume by entity


Select objects via the normal AutoCAD object selection methods. Quicksurf will calculate the volume under the selected entities in cubic drawing units. 3DFACEs, Polyfaces, and 3D polygon meshes are the only entity types that will yield a volume; all other entities are ignored. The status bar will be updated with the total as it is calculated. Volume by entity computes three results: a pos-itive volume for objects above the zero datum (x,y) plane, a nega-tive volume for objects below the zero datum plane, and a grand total.

If you want the volume calculated with reference to a different plane from the zero datum, use the AutoCAD Move command to move the drawn TIN or GRID vertically to the desired level.

Either grid or triangles may be used to compute a volume under a surface, but not both, and they generally yield different results: triangles are treated as flat faces, whereas the grid represents a smoothed surface that passes through all the control points. If the grid is a 3D polygon mesh, a single value of volume for the entire mesh is calculated. If the grid consists of individual 3DFACEs or Polyfaces they are calculated for all selected faces, then summed and reported in the totals.



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If the resultant faces extend above and below zero datum, the included volume between the surface and zero will be reported separately along with the total of the two. If a single face pene-trates through the zero plane, a single net volume is calculated for that face, rather than separate positive and negative portions.

All of Quicksurf’s volume commands will produce identical results when run on the same surface parts. Volumes run on TIN, TGRD and Grid of the same surface will yield slightly dif-ferent results, because of different amounts of curvature informtion carried by the different surface parts. Always visually examine a surface prior to calculating its volume.



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Design Tools

Drape

DRAPE

Modifies AutoCAD drawing entities to conform to their z values to the specified surface. The Configure Drape dialog box controls the specific drape parameters.

Design Tools -> Drape

Surface <current>: selectSelect objects: select

You may not drape onto a surface containing only points.

At the select prompt, select entities to be draped by the normal AutoCAD object selection methods. When selection is completed press enter and all selected entities will be draped onto the speci-fied surface. A surface must contain a TIN, TGRD or Grid before you may drape onto it. You may not drape onto a surface contain-ing just Points.

Results of draping

Any AutoCAD entity may be draped, but the results are not nec-essarily meaningful. The following rules apply:

3D polylines: A new 3D polyline having the original planform and conforming to the surface z values is generated.

2D polylines, lines, circles, arcs: The entity is converted to a 3D polyline having the same planform and conforming to the surface z values. Since a contour is a 2D polyline of constant elevation, draping it on the surface from which it was generated will have no effect except to change it to a 3D polyline with constant z val-ues.

Text, solids, inserted blocks: Entity’s z value is altered to conformto the surface at the insertion point. If you need to drape the components of a block, explode the block, then drape the comnents.

Design Tools Page 143


Drape replaces the original entity with the new draped entity. If you want both the original entity and the new draped entity, make a copy of the entity prior to draping it.

Drape and curvature

When draping to the TIN, Drape honors the Derivatives setting in the Configure Grid dialog box. If Derivatives is set to None, objects are draped to the planar faces of the TIN, the same as selecting Planar TIN. If Derivatives is set to 1st or 2nd, drape will honor the curved shape of the mathematical surface.

Drape and boundaries

Drape honors any boundaries currently in effect and only drapes those portions of the selected objects within those boundaries. If a polyline entity to be draped extends across a boundary polygon, only the part within the boundary is draped to create a 3D polyline and those parts outside of the boundary are erased.

Draping drawing entities

Page 144 Design Tools


Drape configuration

The Configure Drape dialog controls drape parameters such as drape step for vertex densification and which surface part is draped upon. See Configuring Drape on page 211 of the Config-uring Quicksurf chapter for details.

Using Drape

Drape is a very powerful tool. It may be used to "solve" for the Z value of a surface at a group of points such as construction stake-out plans, fluid flow or finite difference model nodes. It is partic-ularly useful for combining 2D maps and 3D models of the same area, by converting 2D map data into 3D data draped on topogra-phy. Any line or polyline draped onto the surface becomes a 3D profile. Exploded hatch patterns may be draped on a surface to create 3D thematic maps.

Flatten

FLATTEN

Flatten creates an 2D elevation profile of a 3D polyline. Typi-cally the 3D polyline being flattened has been draped so it lies within the surface.

Profile produced by Flatten

The Flatten command prompts for 3D polyline(s) to flatten and then asks questions regarding graph scaling and labeling. The first vertex of the 3D polyline selected becomes the left end of the



profile. Flatten and Cross-section expect polylines drawn left to right. Use the Swap ends command to reverse any 3D polylines which are drawn in the wrong direction prior to using Flatten.

Design Tools -> Flatten


Vertical multiplier <1>:Text size for labeling <13>:Base elevation for grid / Auto <Auto>:Draw grid background <Yes>:Vertical spacing <20>:Vertical labeling interval <2>:Horizontal spacing <40>:Horizontal labeling interval <5>:

Origin: select point[Origin of 2nd: select point]

Note: The first vertex of the selected 3D polyline will be the left side of the flattened profile.

Select draped 3D polylines to be flattened via the normal AutoCAD object selection methods. You will then be prompted for the following graph parameters:

Vertical multiplier

The vertical exaggeration applied to the flattened profile. The default is one.

Text size for labeling

The text size for the numerical labels in drawing units.

Base elevation for grid

The lowest elevation shown on the flattened profile.

Draw grid background

Controls whether a gray background grid is drawn behind the profile line.



Vertical spacing

The vertical spacing between background lines on the profile in the same units as the Z units of the 3D polyline.

Vertical labeling interval

The interval for labeling background lines. 1 labels every line, 2 labels every other line, 3 labels every third line, etc.

Horizontal spacing

The horizontal spacing between background lines on the profile in the same units as the X and Y units of the 3D polyline.

Horizontal labeling interval

The interval for labeling background lines. 1 labels every line, 2 labels every other line, 3 labels every third line, etc.

If more than one profile is selected, Quicksurf will ask for additional origins.

At the origin prompt, select a point on the drawing to serve as the lower left origin of the flattened representation. Y coordinates on the flattened drawing, relative to the origin, will correspond to the original Z coordinates. X coordinates on the flattened profile cor-respond to distance along the 3D polyline, with the left end of the profile corresponding to the first vertex of the 3D polyline selected.

Cross-section

SECT

The terms profile and cross section are used interchangeably here.

The Cross section command creates a 2D profile or cross-section of a surface. You specify a line or polyline representing a line of section and a surface name. A line of section represents the plan view path where the profile or section is to be cut.



2D section produced by Cross section

The Cross section command is different from the Flatten com-mand. Cross section only uses the plan view information of the line of section and obtains its Z information directly from the named surface. Flatten obtains its Z information from the verti-ces of the 3D polyline supplied and cannot use 2D drawing enti-ties as lines of section. Cross section can use 2D or 3D entities as lines of section, although 2D entities are preferred.

Vertical and horizontal scaling, labeling, background grid and destination layers are controlled the Configure Section dialog box. See the configuring Quicksurf chapter for a complete description of the many options in the Configure Section dialog box.

Design Tools -> Cross section

Surface <.>: enter surface nameSelect sections...Select objects: select line or polylineSelect objects: press returnNone/Show/Draw/Redraw <Show>: DLower left corner: pickUpper right corner: pick

Note: The first vertex of the selected polyline will be the left side of the resulting cross-section.

After selecting a line of section and a surface name and whether to show or draw the section, you are prompted to supply the two corners of a rectangular area in which the section will be drawn. The section will be scaled to fit within the rectangle. If a specific horizontal and vertical scale has been specified in the Configure Section dialog box, only the lower left corner is prompted for and the section is drawn at the specified scale.



The x coordinates on the resulting cross-section correspond to distance along the line of section polyline, with the left end of the cross-section corresponding to the first vertex of the polyline selected. Use the Swap ends command to reverse any polylines which are drawn in the wrong direction prior to using Cross-sec-tion.

Uses the Derivatives set-ting in Configure Grid.

Cross-section uses Drape internally, and therefore uses the Deriv-atives setting in Configure Grid. Setting Derivatives to None will produce sections based on the planar faces of the TIN. Deriva-tives set to 2nd will honor surface curvature.

For most uses, Cross section replaces the Drape - Flatten combi-nation used to create a profiles or cross sections in earlier ver-sions of Quicksurf.

Intersect slope

ISLOPE

Intersect slope projects a user-specified slope from a 3D polyline until it intersects the current surface and draws a new 3D polyline where the projected slope and current surface intersect. Addi-tional lines may be created by Intersect slope, if needed, to pro-duce smooth radial corners or to properly represent V-shaped areas where two fill surfaces merge. The lines and 3D polylines created by Intersect slope will subsequently be used as break lines.

The target surface must contain a TIN, TGRD or grid prior to run-ning Intersect slope.

Design Tools -> Intersect Slope

Surface name <current>: select surface to project uponSelect control linesReturn to select all orSelect objects: select control polyline (2D or 3D)Setup dialog <Y>: Yes to access Configure Slopes dialog



The Configure Slopes dialog box may be invoked in-line to spec-ify projection slope angles and directions relative to the control line. The slope specifications from this configuration dialog con-trol the behavior of the Intersect slope command.

Configure Slopes

SETSLOPE

The settings in the Configure Slopes dialog box are used by both the Intersect slope and the Apply section commands. Both these commands draw 3D polylines representing the intersection of a slope projected from a 3D polyline and a surface.

Configure Slopes dialog

Please read the comprehensive description of the Configure Slopes dialog in the Configuring Quicksurf chapter.



About slope - surface intersections

Many problems in surface modeling concern determining where a slope from a known path, typically a 3D polyline, intersects a sur-face. Design of building pads, stock ponds, roadways, stockpiles and geologic faults all encounter this problem. Quicksurf will automatically determine the 3D intersection of a given slope from a control line with any surface. The control line is incrementally traversed and a vector is projected up and/or down at the speci-fied slopes until it intersects the surface. This intersection point is then used as a vertex of the 3D polyline being created at the intersection of the projected slope and the surface. The process is repeated for each step down the control line. The result is a 3D polyline representing the intersection of the projected slopes and the surface. This 3D polyline may represent the toe of a fill or the head of a cut. Typically these 3D polylines are then extracted as break lines and a TIN or triangulated grid is then built. These 3D polylines are used as break lines because they typically represent abrupt changes of surface slope, such as at the toe of a fill slope or the head of a road cut.

Projecting slopes from a 3D polyline



Vertical align

VALIGN

Reverses the effect of the Flatten command by applying the verti-cal (Y axis) profile of a modified polyline from the 2D vertical profile back to the original horizontal alignment polyline used to create the profile. Some definitions will help understand this pro-cess:

Horizontal alignment polyline

The 2D or 3D polyline representing the horizontal alignment of the profile in plan view. Only the X,Y information of this entity is used. 2D polylines will have fewer vertices than draped 3D polylines, therefore reducing the number of unnecessary vertices.

Original vertical profile

The 2D polyline representing the original vertical profile as pro-duced by Flatten or Cross-section.

Adjusted vertical profile

The design vertical alignment (2D polyline) is drawn right on top of the original vertical profile graph. The adjusted and original profile polylines must be aligned (in the X dimension) at their left ends for proper operation of Vertical align.

New vertical alignment

The new 3D polyline created by Vertical align using the Z values from adjusted vertical profile polyline and the XY alignment from the horizontal alignment polyline.

This command is principally used in road design and allows you to alter the vertical profile of a road to suit engineering require-ments and generate its 3D representation. Geologists may use it for 3D fault line positioning.



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Vertical align

Although this illustration is in an oblique view, Vertical Align should be run from plan view.

Workflow

Typically Vertical align is used in conjunction with Drape, Flatten (or Cross-section) and Apply section in the following order:

• Draw road centerline (2D polyline) in plan view• Drape road centerline onto existing topography surface• Use Flatten to build 2D profile of centerline• Draw new vertical road profile on the above profile graph• Use Vertical align to apply the new profile to the draped line• This will be the control line for Apply section• Draw the road cross-section template(s) as 2D polylines• Use Apply section to build the road break lines• Use Extract to Surface for the undisturbed topo entities• Use Extract breaks for the road break lines• Use TGRD to build the new surface

By the time you run the Vertical align command you will have a draped 3D polyline on the surface, a 2D flattened profile of tha3D polyline and a new 2D polyline on the flattened profile reprsenting the new vertical alignment.



Design Tools -> Vertical align

Select vertical alignment...Return to select all visible orSelect objects: select adjusted vertical profile 2D polylineSelect base point: snap to lower left corner of 2D profile graph axesSet elevation of base point <default>: enter elevation of base pointVertical multiplier <1>: enter factor used when creating 2D profileSelect horizontal alignments for applying vertical alignment... selectErase original horizontal alignment polyline? <Y>: enterApplying new vertical alignment...

At the first select prompt, select the newly-created 2D adjusted vertical profile polyline that will provide the vertical alignment. At the base point prompt, snap to the point representing the origin of the vertical alignment graph; normally this will be the same origin point you selected for the Flatten or Cross-section com-mand. Supply the elevation of this point as requested; normally it will be the lowest elevation value marked on the graph. At the vertical multiplier prompt, enter the same vertical multiplier used when creating the flattened profile.

Finally, select the horizontal alignment polyline. A new 3D polyline will be created having the original horizontal alignment with the Z values of its vertices adjusted to reflect the new verti-cal alignment. You are prompted whether to erase the original horizontal alignment polyline. Generally you will want to erase this original polyline if it is a 3D polyline created with Drape, but perhaps leave it if it a 2D centerline polyline which may be needed later. If you choose not to erase the original polyline, it is moved to the frozen layer named OLD_DATA to avoid confusion.

Vertical align may be used with the Cross-section command instead of Drape and Flatten. Cross-section builds the 2D section directly from the surface without draping the 2D polyline used for the horizontal alignment. Vertical align will accept this 2D polyline for the horizontal alignment and build a new 3D polyline representing the new vertical alignment.



Apply section

APSEC

Apply section sweeps a cross section template along a control line (3D polyline) to create a set of new 3D polylines to be used as break lines. The cross section template is a 2D polyline typically representing a road cross section. Several different templates may be used along a section of road with either linear or spline transitions between different sections. The slopes and transition type (if any) are defined in the Configure Slopes dialog box.

Each vertex on the cross section template leaves a 3D polyline trail as the template is swept along the control line. Two addi-tional 3D polylines are drawn by projecting user-specified slopes from the ends of the template until they intersect the surface.

Any visible POINT drawing entities between the outermost break lines are moved to a frozen layer called OLD_DATA. The points outside the disturbed area should then be extracted to a new sur-face and the new 3D polylines added as break lines. Building a TGRD on this data set represents the new design topography.

Apply section is run once for each control line or segment.

Apply section creates break lines



Workflow

Apply section is usually used in the following sequence when designing a road:

• Draw road centerline (2D polyline) in plan view• Drape road centerline onto existing topography surface• Use Flatten to build 2D profile of centerline• Draw new vertical road profile on the above profile graph• Use Vertical align to apply the new profile to the draped line• This will be the control line for Apply section• Draw the road cross-section template(s) as 2D polylines• Use Apply section to build the road break lines• Use Extract to Surface for the undisturbed topo entities• Use Extract breaks for the road break lines• Use TGRD to build the new surface

Using Apply section to create a road



Viewing the resulting TGRD with Surface view

Viewing the resulting TGRD with Surface view

The Surface view command is a handy way to examine your design from various perspective views. The triangulated grid shown here is the same one built in the previous example figures.



Apply section invokes the Configure Slopes dialog then prompts for cross-section template(s) and control line.

Design Tools -> Apply section

Invokes Configure Slopes dialog to set slopes and transitions.

Surface <current>: select or press ? to pick from surface listSelect starting section...Select objects: select cross-section templateControl line point on starting cross-section: select point using osnapUse a different ending section <N>: YSelect ending section...Select objects: select cross-section templateControl line point on ending cross-section: select point using osnapSelect control line: selectApply to entire Control line or Segment <C>: S Define segment along control line...Distance/<Select beginning point>: pick point on control line using osnap

or press D then type in distance numberDistance/<Select ending point>: pick point along control line using osnap

or press D then type in distance numberNone/Show/Draw/Redraw <Show>: DApplying cross-section...Finished

The prompt dialog shown above is the longest possible case. If you are simply applying one cross-section along an entire control line, many fewer questions are asked.

Apply section requires slope and transition definitions, starting and ending cross-section polylines, and a control line.

Slope and transition control

User-specified slopes are projected up or down from the end points of the cross-section being applied until they intersect the surface. A 3D polyline is drawn representing this slope-surface intersection. Slope and transition control is specified in the Con-figure Slopes dialog box which is automatically invoked by Apply section. The complete description of this dialog is Chapter 7 on page 225.



Surface

Specify the surface to be used when calculating slope-surface intersections off either end of the cross-section template. This may be the existing topography surface or an intermediate design surface. The surface should at least have a TIN present (not points only), so that projecting the slopes will return an intersec-tion.

Starting Cross-section

A cross-section template is a 2D polyline, drawn in the XY plane, representing the road cross-section. This polyline is swept along the control line to produce a set of 3D polylines, one for each ver-tex of the cross-section. Two additional 3D polylines are created representing the intersection of the slope projected from the end points of the cross-section polyline and the topographic surface. These 3D polylines will be used as break lines when creating the new design surface.

After selecting a cross-section polyline, you are prompted to select a control line point on the cross-section. Conceptually, this represents the point on the cross-section which is attached to the control line as the cross-section is swept down the control line. Typically this will be a vertex or a mid-point on the 2D cross-sec-tion polyline. If so, use OSNAP to ENDpoint or MIDpoint to insure proper alignment. Although the attachment point is normally on the cross-section polyline, this is not required. The relative posi-tion between the cross-section polyline and the attachment point is used when applying the section.

Ending Cross-section

If a transition between two different sections is specified, a sec-ond cross-section template must be selected. The same questions will be asked for the second cross-section polyline. The nature of the transition between the two cross-sections is controlled by the settings in the Configure Slopes dialog.



of

nt. s the

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Control line

The control line is a 3D polyline representing the path to which the cross-section template(s) will be applied. This control polyline is typically the 3D path of the road centerline. The direction from the beginning to the end of the control polyline becomes important when using transitions between different cross-sections or when defining a segment in terms of distances. The Swap ends command (in the utilities menu) will display the direction of a polyline and allow you to reverse its direction if needed.

The control line represents the final design path for the road and usually is the result of using Vertical align to design the road’s vertical curvature.

Segment

Apply section can operate on an entire control line or just a partthe control line using the Segment option. If you select the Seg-ment option, you are prompted to pick a point or specify a dis-tance along the control line for the start and end of the segmeIf you graphically pick points on the control line, the segment idefined between the points. You may specify distances from beginning of the control line by answering D to the Distance/<Select endpoint> prompt, then keying in the distance value. Thedistances along the 3D control line are measured from the firsvertex of the control line are used to define the segment. Thedirection of the control line may be verified or adjusted using tSwap ends command.

See Chapter 23 (page 367) for examples using Apply section.



Build surface

QSBLD

Many surface construction problems entail draping points, lines or polylines onto temporary construction surfaces. The resulting draped entities will then be extracted as either points or break lines to create a new design surface. The Build surface command builds planes, cones, or surfaces of revolved sections to use as temporary construction surfaces. Each surface is created within the specified XY window.

Design Tools -> Build surface

Build surfaces dialog

These commands will prompt for points, lines and angles as nec-essary. Normal AutoCAD selection methods apply, including object snaps. Angles are specified in degrees by default, but may be changed using the Configure Units dialog. A surface is created in the results <.> surface within the defined window, ready for draping. Any pre-existing contents of the results <.> surface are lost. If the results surface contains data which will be overwrit-ten, a warning message is displayed in the lower left corner on the dialog box, as shown.



Plane

A plane may be specified by supplying three points, a line and a point or a line and a slope.

Cone

A cone is specified by selecting a point representing the apex of the cone and a slope. Positive angles extend up from the point and negative angles extend down from the point. Angles are mea-sured from the XY plane. The axis of the cone will be parallel to the Z axis.

A partial cone may be created by specifying less than 360 degrees in the Start rotation and End rotation edit boxes. Horizontal angles are measured based on the AutoCAD Units command set-ting. By default angles are measured counter-clockwise from the +X axis, unless redefined within the Units command.

Revolve Section

A 2D polyline section is revolved around a point to create a sur-face. The section to be revolved may be a drawn 2D polyline or a section specified by pairs of distances and angles in the Standard Section dialog box. After selecting Revolve Section and click-ing on OK, the following prompts appear:

Center point: enter or snap to objectStandard section / User section <User>: select

If you select a User section, you are prompted to select a 2D polyline representing the section to be revolved. The first vertex of the selected polyline is attached to the point and the polyline is revolved through the angular sweep specified in the Start rota-tion and End rotation boxes. Horizontal angles are measured the same as for cones.

If you select Standard section, the following dialog box appears.



Standard sections for Revolve Section

Standard sections are described by pairs of distances and angles from the first vertex. The first segment is labeled A, the second B, and so on, in the dimensions section. The sections shown on the left side of the dialog box do not represent the geometry of the section, only the number of segments a section will have. The geometry is described in the dimensions section of the dialog box.

By clicking on a section icon, the corresponding number of seg-ments will be highlighted in the dimensions section. For exam-ple, clicking on the upper right icon will select a three segment section. This will cause dimensions A, B and C to be enabled and D through H to be grayed out. For each segment specify the dis-tance and slope from the previous segment.

Upon pressing OK, the section described will be revolved through the angular sweep specified in the Start rotation and End rotation boxes. The results will be in the <.> surface.



Intersect surface

The intersection between two surfaces may be described with a 3D polyline. Surface intersections may be manually computed by creating at least a TIN for each surface, subtracting the sur-faces from one another with surface operations, then drawing (not showing) the zero contour. (An easy way to draw only the zero contour is to temporarily set a very large contour interval.) This zero contour represents the plan view trace of the surface inter-section, but is not at the correct Z elevation. The contour may then be draped back upon either of the two original surfaces to create a 3D polyline representing the 3D surface to surface inter-section.

Surface region

REGION

Surface region creates a polyface mesh of a surface within one or more arbitrary boundaries. In this way polyface meshes repre-senting patches of a surface may be created. This is useful for breaking areas of a surface into component parts which may have different properties (such as roadway versus shoulder versus grass). For rendering purposes it is convenient to break a surface up into patches which will be assigned different materials (such as fairway versus green versus rough).

Design Tools -> Surface region

Surface <current>: selectSelect BoundarySelect objects: select closed polylines



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The Surface region command creates a polyface mesh represent-ing the surface within the specified boundary polygon(s). If the number of faces exceeds AutoCAD’s face limit for polyface meshes the surface region is automatically partitioned into muple polyface meshes. The internal vertices of the polyface meshes created have the same location that grid nodes wouldhave. The spacing of the internal nodes is controlled by the csize parameters in the Configure Grid dialog box.

One polyface mesh entity is created each time the command executed, unless the face limit forces multiple meshes to be cated. This means that selecting two non-overlapping boundarpolygons will create one polyface mesh entity consisting of twunconnected surface patches. This is an advantage if you wamake all the greens one object and all the sand traps a differeobject in golf course design for example. If you require each mesh patch to be a separate entity, run the Surface region com-mand multiple times, selecting the boundaries one by one.

If only points are in the surface when the command is run, a Tand derivatives are automatically calculated. If break lines arepresent, they are honored exactly.

The Surface region command handles the edge of the resultingTIN with great care to prevent any triangulation artifacts such long slender triangles which are nearly vertical.

Extrapolate

Extsurf

Extrapolate uses local triangulation and surface gradients to adjust the Z values of AutoCAD drawing entities which lie adjacent to, but not overlying a surface. Points, lines, polylines ancircles are the only entities modified. Extrapolate functions simi-lar to Drape in the sense that it does not affect the plan view shape of a chosen line or polyline, it only modifies the Z valuesthe vertices. Point, line and polyline entities have their Z valu



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changed. Extrapolate adds new densified vertices to lines or polylines just like Drape. The Drape Step setting (in Configure Drape dialog) controls the spacing of any newly added vertices.

Extrapolate is designed to be used to adjust the elevation of enti-ties lying a short distance off of the edge of a surface. A few new points may be drawn, adjusted with Extrapolate, then used to extend a surface. A 2D polyline representing the plan view of a geologic fault may be turned into a 3D polyline using only con-trol points on one side of the fault. Entities adjusted with this command serve as a starting point for surface editing. As with any extrapolation, the result should be viewed with great suspi-cion and adjusted as necessary.

Design Tools -> Extrapolate

Surface <Current>: selectSelect objects: select entities to be adjusted

To extrapolate based upon a local subset of points, create a new surface with Extract to surface containing only the points desired. See Chapter 27 (page 407) on geologic faulting for examples of local extrapolation. A typical work flow for creating an extrapo-lated 3D polyline might include

Insure that the surface has enough area to rely on sur-face gradients for extrapo-lation. Extrapolating perpendicular to a long, skinny surface only a few points wide may yield meaningless results.

• Create a new surface containing the desired subset of poi

• Draw the 2D polyline to be extrapolated.

• Use Extrapolate to create a 3D polyline from the 2D polyline

• Use Flatten and Vertical Align to examine and further modify its vertical profile if needed.

• Use the appropriate Extract command to add the new data tothe surface, resulting in a new modified surface.

• 3D polylines created in this way may be used as breaklinesjust extracted as additional data points to extend a surface



Utilities

Elevation utilities

TrackZ

TRACKZ

Provides a continuous readout of the Z value of the a surface at the cursor position. A TIN, Grid or TGRD must be present for the surface being examined. TrackZ will not work with just points.

Utilities -> Elevation utilities -> Track Z

The elevation (z) value of the current surface at the present posi-tion of the cursor will be displayed at the top left of the AutoCAD drawing screen. If the cursor does not overlie the surface, a sur-face elevation of UNDEFINED will be reported. Track Z may be run from plan view or an oblique view. From an oblique view, a vertical probe will extend from the cursor crosshairs to the sur-face.

Track Z utilizes drape internally, so the elevation reported is based on the surface part (TIN,TGRD, grid) used by drape. This is specified in the Configure Drape dialog box. When sampling the TIN, Track Z also honors the Derivative setting in the Config-ure Grid dialog. If Derivative is set to None, Track Z returns the elevation based on the planar faces of the TIN, otherwise it returns the elevation using the slope and curvature information associated with the surface.

Track Z is a very fast tool for checking surface values when edit-ing a surface. Track Z may also be accessed from the sidebar menu if present.

Utilities Page 167


Display Z of entity

DELEV

Displays the elevation of a selected drawing entity.

Utilities -> Elevation utilities -> Display Z of entity

Select object: select

This command will not operate on 3D POLYLINEs, since they have multiple z values associated with them.

Select one object via the normal AutoCAD object selection meth-ods. The elevation (z value) associated with the object will be dis-played on the command line. The elevation of each object you select is displayed. Press return to exit.

Change Z of entity

CELEV

Alters the elevation values of a group of selected drawing enti-ties.

Utilities -> Elevation utilities -> Change Z of Entity

Select objects: selectSelect object with desired elevation or <Enter>: select

Select as many objects as desired via the normal AutoCAD object selection methods and press enter when done. At the next prompt, you may select an object which has the elevation you want to set for the other objects. If you want to enter a discrete value from the keyboard press Enter, and you will be prompted for a value. In either case, the elevations (z values) associated with all the selected objects will be set to the specified value.

Change Z of entity is very useful for moving groups of 2D polylines to their correct elevation.

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Change Z of entity will not operate on 3D POLYLINEs such as generated by the Drape command, since they have multiple z val-ues associated with them. It is very useful for setting the z values of groups of 2D polylines such as contours.

Set Z

SETZ

Sets the current elevation to that of a selected drawing entity.

Utilities -> Elevation utilities -> Set Z

Select objects: select

The current elevation is set to the z value of the selected object. This command is commonly used while surface editing, typically to set the current elevation to that of a nearby point or contour. Do not select 3D polyline or various mesh objects, because these objects have multiple Z values.

Scale Z of entities

SCALEZ

Multiplies the Z value of selected AutoCAD entities by the user supplied scale factor. The X and Y coordinates are not affected.

Utilities -> Elevation utilities -> Scale Z

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Select by Z

SELZ

Creates an AutoCAD selection set of entities from one layer which lie between specified minimum and maximum elevations.

Utilities -> Elevation utilities -> Select by Z

Layer <current>: selectMinimum Z <-inf>: value or return for no minimumMaximum Z <+inf>: value or return for no maximum

By specifying a layer and a Z range only those drawing entities on that layer and within the Z range are selected. This selection set may then be used with any command (such as erase, chprop, dpost) which accepts a PREVIOUS selection set.

For example, assume layer TOPO contains a set of contours from zero to 500 meters at a 10 meter contour interval and you want to change the color of all contours between 250 and 350 meters to red. The following command sequence would do this.

Select by Z

Layer <current>: TOPOMinimum Z <-inf>: 249Maximum Z <+inf>: 35111 selected

CHPROPSelect objects: P (This selects the previous selection set)11 selectedChange what property (Color/LAyer/LType/Thickness)? CNew Color <varies>: Red

Select by Z may similarly be used to selectively erase, change layers of contours or drawn points or post only a range of values using DPOST. This may all be accomplished without turning on and off layers. By accepting the <-inf> and <+inf> range defaults, Select by Z simply selects everything on a layer.

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Quicksurf utilities

Generate terrain

TGEN

Generates a randomized terrain map for demonstration or training purposes. The terrain type generated will be a random choice of Flat, Rugged, Rolling or Mountainous. You will be prompted for the number of points desired; as soon as you enter this a point set will be generated and written into the results <.> surface.

Utilities -> Quicksurf utilities -> Generate Terrain

Large test datasets may be built with this command.

Number of points to be generated <1000>:Select number of pointsGenerating [Flat, Rugged, Rolling, Mountainous] TerrainFinished Generating Terrain

The random number generator used by this command is seeded by the option parameter GENSEED. You may obtain a repeatable pseudorandom sequence of points by manually setting this parameter by typing:

QSOPTKeyword: GenseedSeed number for terrain generator: value

Set option by keyword

QSOPT

Allows access to set any Quicksurf variable directly. Typing QSOPT at the command prompt will prompt you for a keyword and a value for that keyword. The keywords are listed on the left side of the Quicksurf configuration file (.QCF), see page 419. Expert use only.

Utilities Page 171


Command list

QS

Typing QS at the command prompt displays a list of all Quicksurf ADS keyboard commands on the text screen.

Utilities -> Quicksurf utilities -> Command list

Quicksurf Version

QSVER

This reports the current version number of the Quicksurf program you are using. Maintenance releases of Quicksurf may be avail-able on the Schreiber WWW site. Your version number is the key to determining if a newer version is available.

Utilities -> Quicksurf utilities -> Quicksurf Version

TIN edge

TINEDGE

The Tin edge command displays the 3D polyline representing the edge of the TIN of the current surface. Both show and draw modes are supported.

Utilities -> Quicksurf utilities -> TIN edge


The 3D polyline representing the TIN edge is shown or drawn as requested. This 3D polyline may be subsequently used as a break line or a boundary.

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3D flowlines

FLOW

Draws 3D polylines on the current surface representing flowlines. These 3D polylines are aligned with the maximum gradient of the current surface, representing the path a drop of water would take if allowed to flow down the surface. From plan view, flowlines appear to cross contours at right angles. Flowlines may be drawn "uphill", "downhill", or both, from a user specified starting posi-tion. A flowline will continue up or down gradient from the start-ing point until it reaches a local high or low point, or encounters the edge of the model.

3D Flow lines over topographic surface

The 3D flowline command is invoked by selecting

3D flowlines uses the cur-rent surface in memory. This surface must have at least a TIN, not just points.

Utilities -> Quicksurf utilities -> 3D flowlines

Surface <current>: selectDirection: Up/Down/Both <Both>: selectStep length: enter value or pick graphicallySelect objects or press enter for interactive: select

Utilities Page 173


After specifying the surface to use, choose whether the flowlines are to be drawn down-gradient from the starting point, up-gradi-ent, or in both directions.

The step length controls the length of each segment of the 3D polyline. Because the flowline stops at local high or low points, the step length also directly affects what "local" is defined as. Selecting too short a step length will cause flowlines to stop in every mud puddle because it is a local low. Selecting too long a step length results in coarse, angular flowlines. For any given surface, a few experiments with step length will rapidly converge on an appropriate value for that surface.

The starting point(s) of the flowlines are chosen either by select-ing objects or by pressing Enter to use the interactive mode. If you select objects, their X,Y locations are used as starting points. Selecting a polyline causes each vertex of the polyline to be used as a starting point. In the interactive mode you will be prompted for each starting point.

If you need to have flowlines start at equally spaced intervals along a contour, use the AutoCAD Measure command to create a set of equidistant points along the contour. Select those points for flowline starting points.

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Grid pedestal

GPED

Draws a polyface mesh pedestal on the base of a grid. Generally used as a finishing touch on a perspective view, to make the grid appear as a solid object. This feature can also improve visualiza-tion of the surface by blocking any view of the underside.

Utilities -> Quicksurf utilities -> Grid Pedestal

Surface <current>:Elevation for base <default>: value or enter for default

The default value offered for the base elevation will be the lowest elevation occurring on the grid; accept this value or enter any other value. A pedestal will be drawn if a grid exists in the current surface; otherwise the operation will fail. The pedestal will extend downward to the specified base elevation.

The pedestal is drawn around the edge of the grid, or the edge of any boundary that is in effect. As long as the grid and the pedes-tal are both drawn with the same boundaries in effect they will always align properly. Nested boundaries produce nested pedes-tals.

Moving average

MAVG

Creates a moving average of a surface. This is a simple surface smoothing routine which generates a gridded array of points based on the <.> surface. The resulting points may then be extracted to generate a smoothed surface. This routine may be used to de-sample a data set to sparser control or as an averaging filter.

Utilities Page 175


A moving square filter matrix is overlain on each new grid cell location and the original surface is sampled at each node of the matrix. The resulting values are averaged and this elevation is assigned to a new grid point drawn on the current layer. The pro-cedure is repeated for each grid node.

Utilities -> Quicksurf utilities -> Moving Average

Surface <current>: selectMatrix size: value (1,2,3,4,5,...)Cell size: value or pick graphicallyLower left corner: pickUpper right corner: pick

Matrix size

Number of rows and columns in the moving square array that is sampled around each grid point to be generated. All samples are weighted equally. A value of 1 means no averaging. Low values are recommended (1 - 5). The computation time increases as the square of the matrix size.

Cell size

Row and column spacing of resulting grid of points as well as the spacing of rows and columns in the sampling matrix.

Window

Lower left corner and upper right corner for the new grid points. This may extend beyond limits of current surface. The lower left is exact, upper right approximate.Once the new grid nodes have been drawn, use Extract to surface (QSX) to extract them, then contour the results <.> surface to view the smoothing.

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Variogram design

VARIO

Kriging is a geostatistical method of surface estimation which uti-

lizes the relationship between variance (in Z) versus the statis-tical distance between data points. Kriging forces the mean error to zero and attempts to minimize the variance of the errors.

The statistical background of kriging is deep and rich and beyond the scope of this manual. Kriging is a powerful tool, but requires an understanding of underlying statistics. The resulting grid and contours from kriging are utterly dependent upon proper vario-gram design. A poorly designed variogram for a given data set can produce an erroneous surface or cause the mathematics to be unstable and fail to produce a surface at all. The variogram design tool within Quicksurf is the Vario command, which inter-actively creates semi-variograms.

The relation between variance and statistical distance is expressed as a semi-variogram, which plots semivariance along the Y axis and distance along the X axis.

A gaussian semi-variogram

Variogram design consists of fitting a function which describes variance versus distance for the data set being mapped. The Vario command displays a histogram of variance versus distance based upon the points in the current surface. The histogram is displayed

σ2

γ h( )h( )

Range

Nugget

Sill

Distance (h)

γ h( )

Utilities Page 177


as a line graph, rather than a bar graph, with the estimated sill line draw horizontally. The variogram is designed graphically right on top of the displayed graph. You are prompted for variogram type, nugget, range and sill and the resulting variogram is dis-played. The variogram design may be interactively altered as needed. Once accepted, all subsequent grids produced by the Krige method will use this variogram design.

Utilities -> Quicksurf utilities -> Variogram design

Surface <.>:Number of histogram intervals <24>: valueSelect variogram window first corner: pickSelect second corner: pickVariogram type <default> : specify Linear, Exponential, Spherical, etc.Point at y=nugget <default>: pick graphically or enter valuePoint at range, sill <default>: pick graphically or enter range, sillSelect variogram point below sill <default>: pick graphically or enter pointVariogram finished? <No>: Yes to accept, No to revise variogram

Number of histogram intervals

The inter-point distances of the points in the current surface are grouped into the number of histogram intervals specified. The default of 24 means that the X axis will be divided into 24 histo-gram intervals. The lowest interval starts at a distance of zero and the highest interval ends with the maximum inter-point dis-tance.

Variogram window

The variogram is temporarily displayed in the window you spec-ify. The variogram is shown, not drawn and is removed from the display once the design is accepted. Graphically pick the two corners of a rectangular window in which to place the variogram display.

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Variogram type

Quicksurf supports six types of variogram models.

Types of Variogram models

A Linear variogram does not have a range or sill, as the variance continuously increases with increasing distance. The form is

, where h is distance.

A Gaussian variogram is commonly used to model extremely continuous phenomena. The Gaussian model reaches the sill asymtotically. The range is set at the distance where the vario-gram value is 95% of the sill value. This variogram has an inflec-tion point and parabolic behavior near the origin. This can cause it to fail in cases of closely clustered, but highly variable data. When designing a Gaussian variogram with Vario, you will be asked to supply an "extra" guide point between the nugget and the range,sill point to determine the shape of the Gaussian curve.

The form is , where a is the range.

An Exponential variogram also reaches the sill asymtotically. The range is set at the distance where the variogram value is 95% of the sill value. Exponential variograms are fairly linear at short

distances. The form is , where a is the range.

A Spherical variogram has linear behavior near the origin, but flattens out as it reaches the sill at the a distance equalling the range. The form at distances less than the range is

. This is a very commonly used variogram model.

γ h( ) h=

γ h( ) 1 e3h

2– a2⁄( )

–=

γ h( ) 1 e3h– a⁄( )

–=

γ h( ) 1.5 h a⁄( ) 0.5 h a⁄( )3–=

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A Piecewise continuous variogram consists of two linear seg-ments. The first segment is linear from the nugget to the range, sill point, then constant at the sill value at distances greater than the range.

A Hole variogram is used when modeling periodic data. After supplying the nugget, you are prompted for a point representing the period (wavelength) and the sill; rather than the range,sill.

Nugget

The nugget is the term for the Y-intercept of the variogram curve. This value represents the allowable variance at a distance of zero (i.e. at the data point). A zero nugget forces the surface to pass through each data point exactly; a positive value for the nugget allows for the surface to differ from an actual data point within the specified variance.

Range

The range is a term for the distance beyond which the variance does not change significantly. The range represents a distance beyond which point elevations have little or no influence on the surface Z value being estimated. If the inter-point spacing is larger than the range, the resulting surface surrounding each point will have the shape of the inverted variogram.

Sill

At distances beyond the range, the variance clusters about the mean variance of the entire data set. This mean variance value is referred to as the sill, due to the variogram curve flattening out at this value.

Accepting the variogram design sets the Nugget, Range, Sill and Variogram type in the Configure Grid dialog box. These values are carried in Quicksurf’s configuration file if you save one.

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See the Kriging chapter (page 395) for example usage.

Once you accept a variogram, it is used for any subsequent grid creation using the Krige method. Remember that if you already have a grid present in surface memory, you must recreate it using the surface operation Cell size, Cell count commands, or clear the grid using the surface operations Clear parts button. If you fail to cause the grid to be recalculated, the Grid or Contour commands will simply display based upon the pre-existing grid in surface memory.

This version of Quicksurf supports isotropic kriging. The under-lying assumption is that the data structure is isotropic and that variograms utilizing the direction as well as distance between points would be the same.

There is considerable literature on kriging. Two good introduc-tory references on kriging are

J. Davis. Statistics and Data Analysis in Geology. John Wiley and Sons, New York, NY. 2nd Edition, 1986.

E. Isaaks and R. Srivastava. An Introduction to Applied Geosta-tistics. Oxford University Press, New York, NY. 1989.

Voronoi diagram

VOR

Displays the Voronoi triangles for the TIN of the current surface. The Voronoi triangle vertices represent the circumcenters of the vertices of each triangle of the TIN. A circumcenter is the center of a circle which passes through all three vertices of a TIN trian-gle. To understand this, show a TIN, then run this command and show the Voronoi triangles on top of the TIN.

Utilities Page 181


Polyline utilities

Swap ends

SWAPPOLY

Reverses the order of vertices in a line, 2D or 3D polyline. This is useful to correct entities drawn right to left when the reverse was needed. 3D polylines used with the Flatten, Cross-section and Apply section commands are examples where the left-right sense of a polyline is important.

3D polyline offset

3DOFFSET

Creates a new 3D polyline in which is offset a specified horizon-tal and vertical distance from an original 3D polyline. You are prompted to select a 3D polyline and supply a horizontal and ver-tical offset and whether to offset it to the right or left side. Right and left are defined as if you are standing on the first vertex look-ing at the second vertex of the original 3D polyline. A new 3D polyline is created by offsetting each vertex of the original polyline normal to the plan view of original polyline by the hori-zontal and vertical distances specified. No checking for self intersection or "bow-tie" geometry is done.

Create boundary

CBND

Creates a closed polyline out of a set of lines or polylines which share exact endpoints. For example, four lines forming a square could be selected and a square polyline would be drawn. Such polylines could then be used with the Set Boundary command.

Page 182 Utilities


Make 2D poly

MK2DPOLY

Converts a 3D polyline into a 2D polyline at the elevation you specify. The resulting 2D polyline will have the same number and X, Y location of vertices, but all the vertices will be at the specified elevation.

Merge 3D polyline

3PEDIT

Joins two or more 3D polylines which share exact endpoints into a single new 3D polyline. The original 3D polylines are erased.

Densify vertices

DENSIFY

Densifies vertices of 2D and 3D polylines based upon a user specified step size. New vertices are added to the existing polyline vertices.

Export 3D polyline

XSEIS

Exports a comma delimited ASCII file representing vertices of selected 3D polylines. The line number, vertex number, text label and each vertex (X,Y,Z) is placed in a text file suitable for loading into spreadsheets or database manager. It is a general purpose routine, although it was originally written to export 3D polylines representing seismic lines.

Utilities -> Polyline utilities -> Export 3D polyline

File name: filename to writeLine number or return to exit: specify line number as a prefixStarting vertex no.: value for first vertexIncrement: value for vertex number incrementAlpha label: alphanumeric label for line

Utilities Page 183


A comma-delimited file similar to this is produced:

1, 1, Line one, 4.23, 6.87, 250.021, 2, Line one, 5.26, 7.83, 244.121, 3, Line one, 6.32, 8.49, 238.75...

being Line number, Incremented vertex number, Label, X, Y, Z.Every vertex of the polyline is output. The increment is for cases where each polyline vertex may represent every Nth measure-ment, such as 100, 105, 110, 115,etc.

Polyface utilities

Weld 3D faces

WELD

Creates a polyface mesh from selected group of 3D faces. Not recommended for use with greater than 5000 faces.

Surface area

SAREA

Calculates the surface area of drawn 3D face entities. A polyface mesh must be exploded into 3D faces prior to running SAREA.

Offset 3D mesh

LINER

Creates a polyface mesh offset normal to the surface of an exist-ing polyface mesh. Each vertex of the new mesh is moved a user specified distance normal from the original polyface mesh. The primary usage is for designing pit liners for ponds and landfills.

Page 184 Utilities


- ll and ted

General utilities

Erase selected

ESEL

Erases entities of the same type and on the same layer as the selected entities. For example, selecting a TEXT object on the layer NAMES will erase all TEXT entities on layer NAMES. Text on other layers, and other drawing entities (such as lines or points) on layer NAMES will be unaffected. The unique combination of layer and entity type determines what is erased. Multiple objects may be selected.

Set layer

SETL

Sets the current drawing layer in AutoCAD and turns all other layers off. This has exactly the same effect as issuing the AutoCAD LAYER command, selecting Set, naming a layer and then turning all other layers OFF.

Rubber sheeting

MAP

This command allows you to arbitrarily stretch a map so that it can be overlaid over another map of the same area, when the two maps don’t match because of different scales or projections, printing processes, paper shrinkage, etc.

The MAP command applies a bivariate polynomial transformation to all defined points of the selected objects to achieve themapping. INSERTs, CIRCLEs, ARCs, SHAPEs, TEXT, etc. wibe moved as necessary, but they will retain their size, shape, rotation. Points, lines, 2D and 3D polylines will be rubber sheecorrectly.

Utilities Page 185


ea

-

lar

s--

e

A roughly rectangular matrix of points is established on the origi-nal ("From") drawing and a corresponding set of point locations for the resulting ("To") map is given. The set of “From” points will be mapped onto a set of “To” points, and the remaining arof the map will be stretched, warped, folded, or whatever is required to obtain a continuous fit.

The selection of the two sets of points is very critical for good results.

First, the overall size of the “From” map should be close to thesize of the “To” map. If it is not, use the AutoCAD SCALE command to adjust its size before rubber sheeting.

Second, the set of “From” points must be a generally rectanguhorizontal grid, with all rows containing the same number of points. Some deviation from a perfect grid is all right, but excesive irregularity may yield very unsatisfactory results. If necessary, use the AutoCAD ROTATE command before using MAP to make the “From” grid approximately horizontal. All points in th“From” set must be distinct.

The only constraint on the “To” grid is that it has to contain thesame number of points as the “From” grid, since every “From”point has to be mapped into a “To” point.

Rubber sheeting

Rows <2>: valueColumns <2>: valueFrom point 0,0: enter X,Y value or pick graphicallyFrom point 0,1: enter X,Y value or pick graphicallyFrom point 1,0: enter X,Y value or pick graphically...To point 0,0: enter X,Y value or pick graphicallyTo point 0,1: enter X,Y value or pick graphicallyTo point 1,0: enter X,Y value or pick graphically......Wait...Z scale factor <1>: value

Page 186 Utilities


or

s

-

w,

Return to select all orSelect objects: select

The selected objects will be transformed to the new geometry.Only the x and y coordinates are involved in the mapping; the z coordinates are only scaled by the selected Z scale factor.

If zero rows are specified, MAP only performs the scaling of z coordinates. If only one row and one column are specified, MAP effectively does just a 2D MOVE.

While there is no limit on the number of rows or columns, large numbers may cause numerical instability, and will take longer to process.

The process of entering the “From” and “To” points is very errprone, and requires that the command be restarted from the beginning in case of any error.

Tilt

TILT

Rotates a drawing entity or group of entities into plan view to aif viewed from a perspective viewpoint. The Tilt command must be executed from a perspective viewpoint.

Tilt


Select the objects to be processed with the normal AutoCAD selection methods. When the Tilt command is complete, the drawing will be in plan view just as if the AutoCAD PLAN commandhad been executed. The objects which were selected for the Tilt command will still appear just as they did in the perspective viebut everything else will be seen in plan.

Utilities Page 187


The primary purpose of this command is to allow both a plan view of contours and an oblique view of a grid to be presented in the same drawing. It is also useful with the Unwrap and Wrap commands, to obtain the most desirable orientation for transfor-mations of spheroidal surfaces.

Untilt

UNTILT

Undoes a previous Tilt operation.

Untilt


Select objects to be processed via the normal AutoCAD object selection methods. The effect of the previous Tilt operation on these objects will be reversed, restoring their previous orienta-tion. It does more than an AutoCAD UNDO operation, because you can select which objects will be untilted.

Wrap to sphere

WRAP

Transforms planes into spheres.

Wrap to sphere

Center <0,0,0>: select center of planeReturn to select all or Select objects: select

Select the origin of the wrapping plane and the objects to be wrapped via the normal AutoCAD point and object selection methods.

Page 188 Utilities


This command does the inverse of the Unwrap to plane com-mand. The selected objects are effectively transformed from an orthogonal into a spherical coordinate system.

The positive z displacement of objects from the center in the orthogonal domain becomes the radius in the spherical domain. X displacement from the center divided by the radius becomes longitude (in radians), and the y displacement divided by the radius becomes latitude. Transformations of x displacements greater than pi times radius, or y displacements greater than pi/2 times radius, or negative z displacements produce interesting but meaningless results.

As a rule Wrap will restore anything that was done with the Unwrap command. The exception is that 2D polylines are changed to 3D polylines by both commands. Since contours gen-erated by Quicksurf are 2D polylines, they are always affected.

Unwrap to plane

UNWRAP

The Unwrap command transforms spheres into planes.

Unwrap to plane

Center <0,0,0>: select center of sphereReturn to select all orSelect objects: select

Select the center of the sphere, then the objects to be unwrapped, via the normal AutoCAD point and object selection methods.

The selected objects are effectively transformed from a spherical into an orthogonal coordinate system.

Utilities Page 189


In the spherical domain, the north pole is in the positive y direc-tion from the center; points in the positive z direction are at lati-tude and longitude of zero, as if one were looking at the center of a globe through the point where the Equator and the Greenwich meridian intersect.

When the objects are unwrapped, radius becomes the z offset from the center, longitude (in radians) times radius becomes the x offset, and latitude times radius becomes the y offset. In cartogra-phy, this is an equidistant cylindrical projection with the principal parallel at the equator.

Note that the unwrapping process creates a discontinuity at longi-tude (180 degrees) and at the poles.

The primary purpose of this command is to allow modeling of generally spheroid objects, such as human heads, mountains with steep sides, molded objects, planets, etc. For best results, the objects should be rotated (using TILT) so that the area of primary interest is at the center of the plan view.

Generally, the sequence Unwrap - Wrap restores positions of all points correctly, while the inverse is not necessarily true.

Unwrap may be used to unwrap control points. The selection of the center is very critical here, and it must be retained for use in any subsequent Wrap operation.

Scale symbols

SCALESYM

Scales selected INSERTs about their centers. Commonly used to resize blocks representing well or survey locations.

Page 190 Utilities


Load ASCII text

LTEXT

Performs a quick and dirty load of an ASCII text file into the drawing as AutoCAD text. The text is inserted on the current layer, in the current text style. The entire file is inserted as if it were following the previous text command. The location of the text is on the next line following any previous text. Place a dummy text line with the TEXT command at the desired location, then run the LTEXT command.

Sequentially number

NUMBER

Sequentially numbers a set of selected objects. The objects are numbered in order of their insertion into the drawing. The num-bering starts at zero and is placed on the current layer in the cur-rent text style and height.

Number triangles

NUMBER

Sequentially numbers a the triangles of a drawn TIN. The num-bering starts at one and is placed on the current layer in the cur-rent text style and height.

Utilities Page 191


er

Rarefy points

RAREFY

Rarefy points operates on a point set which is drawn into the drawing and rarefies the point set based upon inter-point slope and distance. Unwanted points are moved to a different layer.

Rarefy points

Critical distance: distanceMaximum slope <0>: specify slope (as a fraction: 1.0 = 45 degrees)Select objects: select points

Control points that are extremely close to one another are not nec-essary to define a surface, and they may cause severe problems to Quicksurf if there is even a slight error in their coordinates. The Rarefy points routine moves unwanted points from their current layers to the layer TOOCLOSE, so that they can be excluded from extraction by freezing or turning off that layer.

Points are considered unwanted if

1. They are within the user specified critical distance, and

2. The slope between them is greater than or equal to the speci-fied slope.

Only POINT entities are considered, if they are not already on the layer TOOCLOSE. Other entities are ignored.

If only the 2D distance between points is to be considered, the slope should be set to zero (default). This is normally the pre-ferred method. If specified, the slope is interpreted as the abso-lute difference in elevation divided by the 2D distance.

The layer TOOCLOSE may be created a priori, and frozen or turned off, so that unwanted points disappear as Rarefy points identifies them. If the layer doesn’t exist, Rarefy points will cre-ate it, and set its color to blue, but leave it visible. In any clust

Page 192 Utilities


of points that are too close to one another, the point with the low-est Y coordinate will be retained, and others will be moved to TOOCLOSE.

If a large number of points is selected, Rarefy points may run a long time, because of the large number of comparisons it must make between points. It would be more efficient to run Rarefy points only on small areas that contain, or are suspected of con-taining, unwanted points.

Utilities Page 193

Quicksurf

Chapter 7: Configuring Quicksurf

Most aspects of Quicksurf may be configured to suit your specific application. This chapter describes all of the commands on the Configuration sub-menu of the Quicksurf menu. The configura-tion of all Quicksurf option settings may be saved to a named disk file and read back at any time. You may keep as may different configuration files as you wish. Using configuration files will speed your work by avoiding having to re-establish options set-tings.

Configuration files

Quicksurf configuration files are ASCII text files with the exten-sion .QCF. Configuration files are read automatically when Quicksurf is loaded or you open a drawing. When you open a drawing with Quicksurf loaded, configuration files will be searched for in the following order:

1. <drawingname>.QCF2. QS.QCF

If a configuration file with the same name as the drawing exists it is loaded; if not, QS.QCF is loaded if found; if neither is found, Quicksurf uses its internal default settings. The entire path described by the ACAD path variable is searched.

Saving a configuration file with the same name as the current drawing will cause the configuration to be automatically reloaded the next time the drawing is opened. The entire Quicksurf envi-ronment will be restored automatically.

You may create a standard custom configuration by saving your desired settings to QS.QCF in the directory in which Quicksurf is installed. After doing so, any drawing without a custom configu-ration file will use the settings in the QS.QCF file.

Configuration files Page 195


List Configuration

Lists the current Quicksurf option settings to the AutoCAD text screen. The display format is as follows:

;; File: /qs51/qs.qcf; Quicksurf 5.1 Options;;Keyword = Value(s) ; Description;---------------------------------------------------------

curname = ; Current surface namesurfsort = Yes ; Use sort in surface listwindow = Max ; Current working windowacute = 0.0000 ; Triangulation constraintcellsize = Auto ; Cell Sizecellcnt = Auto ; Grid Count...

Approximately 130 entries will be listed. The configuration file is an ASCII text file with the extension .QCF. A full listing of the settings in the default configuration file QS.QCF will be found in Chapter 29 on configuration files.

Although parameters are normally set using the dialog boxes, any keyword which appears in the left side of the .QCF file may be set manually using the QSOPT keyboard command.

Command: QSOPTKeyword: enter keyword

After supplying a keyword, such as cellsize, you will be prompted for a value, along with a brief description of the mean-ing of the option. Enter the value as requested. The new setting will be in effect for the rest of the drawing session unless changed.

Page 196 Configuration files


Read Configuration

Read Configuration

Read options from file <drawingname>: enter filename (no extension)Reading options from file <drawingname.qcf>

Reads option settings from a previously saved configuration file, and makes them active for the current surface and drawing. Enter a file name without the .QCF extension or press enter to accept the default of <drawingname.qcf>. When a drawing is loaded with the AutoCAD Open command, the system will automatically attempt to load options from the default file. If <drawing-name.qcf> is not present Quicksurf will look for a QS.QCF file in along the ACAD search path. If that is not found, Quicksurf will use its internal defaults.

Save Configuration

Save Configuration

Save options to file <drawingname>: enter filename (no extension)Saving options to file <drawingname.qcf>

Saves current configuration settings to a named file. Enter a file name without an extension (.qcf will be appended automatically), or press enter to accept the default of <drawingname.qcf>.

Factory Configuration

Factory Configuration

Resets Quicksurf to its internal defaults.

Version Info

QSVER

Echoes the version number of this Quicksurf program.

Configuration files Page 197


Configure Grid

The Configure Grid dialogue box allows you to set grid cell parameters such as cell size. Widely varying grids can result from various settings of these parameters. Take care when setting them as they will remain in force until they are reset or a new configuration file is loaded.

Configure Grid dialog

Cell Size

Controls the X and Y dimensions of an individual grid cell. Specify the horizontal and vertical cell size (in drawing units) by entering values in the edit boxes. Selecting the Auto checkbox sets the cell size to 0.0 which causes automatic cell size computa-tion based on the Cell Count setting described below. Non-square grid cells may adversely affect contouring.

Cell size is used for both grid and TGRD node spacing.

Page 198 Configure Grid


The cell size option should be used with care, as specifying small cells over a large area causes very large grids to be built. The Cell Size option overrides the maximum number of cells specified in the Number of Cells box. Surface operations Cell Size sets this variable also.

Cell Count

Allows you to specify an exact number of grid cells in the X and Y directions. Select the horizontal and vertical cell count by entering a value in the edit boxes. Selecting the Auto checkbox sets the cell count to 0.0 which causes automatic cell size compu-tation based on the Cell Factor setting described below. Non-square grid cells may adversely affect contouring.

The cell count is overridden by the maximum number of cells allowed as set in the Number of Cells box, meaning if the cell count specified would generate more or less grid cells than the number allowed, the number of grid cells is adjusted up or down until the number of cells falls within the allowed range.

Number of cells

Sets limits on the minimum and maximum number of cells that will be generated in a grid when no grid cell size is specified. Overrides any source of grid cell number selection except the Cell Size option above.

Cell Factor

Controls the number of grid cells created whenever automatic set-ting is selected for both Cell Size and Cell Count. Sets the num-ber of cells to the supplied value times the number of points in the current surface, then adjusts this figure up or down to keep it within the Minimum and Maximum number of cells you speci-fied.

Configure Grid Page 199


Undefined Grid Value

Z value for undefined grid nodes on a 3D polygon mesh. When you perform a Grid / Draw, some mesh nodes around the rectan-gular edges of the mesh may not have a defined elevation in the grid. These undefined mesh nodes will drop to this elevation forming a pedestal effect in the drawn grid. Positive and negative values are accepted.

Grid Registration

Grid registration forces grid cells for different surfaces to be reg-istered (i.e. coincident in X and Y) with other grids created with the same cell size. If you think of grid cell size as representing the wavelength of the grid, grid registration would control the phase of the grid. Only grids created with grid registration enabled are registered. If you need to have registered grids for surfaces with pre-existing (but dissimilar) grids, clear the grids and recreate them with grid registration enabled.

Grid registration is enabled or disabled by toggling the Enable checkbox. The X and Y values for the registration origin are specified in the edit boxes. Grid cells will be located based on the grid cell size and the registration origin.

where is the grid registration origin and n is a positive

integer.

Xi X0 n CellSize×( )+=

Yi Y0 n CellSize×( )+=

X0 Y0, )(



Grid Method

Three methods are available for deriving the grid. The Standard method uses continuous curvature with Delauney triangulation and is suggested for terrain modeling. The Trend method fits a polynomial trend surface to the data for a generalized approxima-tion of a surface. The Krige is a geostatistical method which requires designing a semi-variogram prior to use.

Standard method

The standard method of gridding triangulates the points, calcu-lates slope information (1st and 2nd derivatives) at each point based upon its local neighborhood, the derivative setting and the weighting factor. The Z values of each triangular face of the TIN and its associated slope and curvature is then solved for at a uni-form X, Y spacing to produce a grid. The mathematical surface honors all control points for all selections, but a grid is only a sample of this surface. Too large a grid cell size can produces a poor representation on the surface.

When you select the standard method of gridding in the dialog box the related choices beneath the Standard button are available for modification.

Derivatives

Selecting None produces a grid fitted to the planar faces of the TIN.

Selecting 1st provides a grid with continuous slope (continuous first derivatives). First derivatives are calculated for each vertex of the TIN and then used to derive the grid.

Selecting 2nd provides a grid with continuous slope and curva-ture (continuous first and second derivatives) of which the theo-retical surface honors all control points.



nt

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Selecting 2nd is good for uniformly sampled rolling terrain, but can produce over-shoots with very irregularly sampled data or exponential data, such as concentration data. If an overshoot problem exists in the resulting grid, clear the grid, enable the Honor Local Extrema option and recreate the grid. If the prob-lem persists, either add phantom data points to shape the surface or select the None setting for derivatives and recreate the grid.

The derivative setting affects the following commands:

• Grid • Contour (if contouring on the grid)

• Drape• Cross-section• Surface region• Track Z• Surface operations

Blend Order

Blend order controls how the polynomials representing adjacetriangles are blended into one another. Generally blend order should be set to the same as the Derivatives setting (1 or 2). Iderivatives are set to zero, blend order has no effect.

Weighting

The influence of neighboring control points when calculating slopes is weighted based on the inverse square law by defaulThe degree to which control points influence slope calculationeach other is normally proportional to the inverse square of thdistance between them, thus the default weight is 2. Increasinthis value decreases the influence of more distant points. Spefying 0 results in equal influence between all points. Only nonnegative integers should be used.



Honor local extrema

The z values of the grid may overshoot the values at the control points because of steep slopes caused by control points with large variations in elevation in short horizontal distances. This effect may be greatly reduced by enabling the Honor local extrema check box. This option forces the surface to be horizontal (first derivatives to equal zero) at local lows and highs, thus reducing or eliminating overshoots.

Trend method of gridding

When you select the trend method of gridding in the dialog box the related choices beneath the Trend button are available for modification.

Trend Options

This option builds a surface model based on a polynomial which is a least-squares fit to the points of the current surface. While there is no specific limit on the order of trend surfaces, very high orders may cause instability in calculations, and produce wildly varying surfaces or fail to produce any results at all. The limit depends on the number and distribution of control points, and the



nature of the surface. The practical limits are about trend order 20 (Type 1) or trend order of 14 (Type 2) in the horizontal and vertical. First through fourth order trend surfaces fit most needs. Trend type 1 and 2 are examined separately below.

Trend Type

Trend Type 1 requires only the trend order to be specified. The same trend order is applied to both the X and Y axes. Trend Type 2 requires the trend order in the X and Y axes to be separately specified.

Trend order

The trend order specifies the highest cumulative order of the polynomial. For example, trend order 3 calculates 10 coefficientsfor trend type 1:

The number of coefficients for a type 1 trend is , where m is the specified trend order. The

number of coefficients must always be less than or equal to the number of points.

For example, horizontal trend order of 3 and vertical order 2 cal-culates 12 coefficients for trend type 2:

The number of coefficients for a trend type 2 when both m and n are given is . where m is the horizontal order and n is the vertical order. The number of coefficients must always be less than or equal to the number of points.

a00 a10x a01y a20x2

a11xy a02y2

a30x3

a21x2y a12xy

2a03y

3+ + + + + + + + +

m 1+( ) m 2+( )×( ) 2⁄

a00 a10x a20x2

a30x3

a01y a11xy a21x2y a31x

3y

a02y2

a12xy2

a22x2y

2a32x

3y

2

+ + + + + + +

+ + + +

m 1+( ) n 1+( )×



a a

m-

Krige method of gridding

Kriging is a statistical method of surface modeling which is widely used in ore-grade estimation and mapping of concentra-tion data sets. The theory of kriging is complex and beyond the scope of this manual. To use this technique you must first specify the semi-variogram which describes the covariance of the Z value of the data points versus distance between them. Variogram design may be accomplished through the Variogram design com-mand. The variogram design will completely control the resulting surface. Poorly designed variograms can result in meaningless surfaces or in mathematically unstable surface models.

Kriging configuration

The parameters which describe the variogram are set within this dialog box. The Variogram type, Nugget, Range and Sill are set by the Variogram design command, found in the Quicksurf utili-ties menu. These variables are fully described in the Variogram design command description on page 177.

Quicksurf’s kriging algorithm uses a neighborhood defined byset of “rings” of neighbors (determined by the TIN) to estimatefunction to apply during surface generation at a point. Higher numbers of rings result in better surfaces at the expense of co



ug-

set

i-

er

m-ta-

putation time. Four rings are recommended as a starting point. Too small a neighborhood combined with too small a range will result in surface discontinuities. Beware: Computation time increases as the cube of the number of rings, so use only enough to produce an acceptable surface.

Kriging is slow, almost always slower than any other method of surface modeling because of the very large number of equation solutions required to generate a surface.

The advantages of using kriging for surface modeling are:

• The surface created always honors the data points within nget tolerance.

• The user controls the range or estimation neighborhood.

• The equation used to determine the surface is created andcontrolled completely by the user.

• Better results are obtained on smaller data sets. If the datais very limited the user has better control over the surfaceshape with kriging and should get better results.

The disadvantages of using kriging for surface modeling are:

• Kriging is slow due to the large amount of calculation.

• Kriging is more complex and requires a high level of techncal understanding on the user’s part.

• The larger the range or estimation neighborhood, the slowthe process.

• Surface generation may fail. Certain variogram designs cobined with data sets following certain patterns may be unsble and will not yield solutions.



Configure Contour

The basis for contours (TIN, Grid or TGRD), contour interval, and levels of automatic contouring are controlled by the Config-ure contours dialog.

Configure Contour dialog

Surface for contouring

The surface for contouring selection indicates whether you want the contours generated on the TIN, Grid or TGRD. An Auto set-ting is provided which contours on the grid, unless breaks are present, whereupon it contours on the triangulated grid (TGRD).

Contouring on the TIN builds contours based upon the planar faces of the TIN. Contour lines will be straight lines within any one triangular face of the TIN.

Contouring on the Grid builds contours based upon linear inter-polation within each grid cell. Contour lines will be straight lines within any one grid cell. The coarseness or fineness of contours is a function of grid cell size.

Contouring on the TGRD builds contours based upon the planar faces of the triangulated grid. Contour lines will be straight lines within any one triangular face of the TGRD. The coarseness or fineness of contours is a function of grid cell size used when cre-ating the TGRD.

Configure Contour Page 207


Contour interval

The contour interval is the elevation difference between adjacent contours. You may specify a discrete contour interval, the num-ber of contour interval levels, or choose the automatic setting.

Auto

The Auto check box toggles automatic contour interval calcula-tion. When Auto is selected, the Interval edit box is grayed-out and the Z range of the surface is divided by the number of levels specified below and rounded to an appropriate contour interval.

Interval

Enter the desired contour interval in the edit box. It is possible to set a contour interval which is radically too large or too small. If you do not know the range of your data, choose the Auto check box for the interval and show the contours. Once you determine an appropriate interval, set it in the Interval edit box.

The contour interval may also be set directly from the Quicksurf pull-down menu (Contour Interval) or from the right sidebar menu, if present.

Levels

The number of levels is used for automatic contour interval deter-mination. When the Auto button is selected, the Levels edit box becomes available. The Z range of the surface is divided by the number of levels to determine a rough contour interval, then rounded to an appropriate contour interval.

Range

The range option allows you to only display contours within a specified Z range. This affects both show and draw modes.

Page 208 Configure Contour


Enable range

The enable range check box toggles whether a Z range is used when displaying contours. When Enable range is checked, only those contours within the specified range are displayed. When Enable range is not checked, all contours are displayed.

Min

All contours greater than or equal to the value in the Min edit box and less than or equal to the value in the Max edit box are dis-played.

Max

All contours greater than or equal to the value in the Min edit box and less than or equal to the value in the Max edit box are dis-played.

Elevation list file

You may enter a file name of an ASCII file containing specific Z values, one per line. If a filename is specified, only contours with those Z values within the file are generated. For example, con-sider an elevation file containing the following:

Logarithmic contours using an elevation file.

.01

.101101001000

Using this elevation file would cause only the six logarithmic contours specified to be drawn.

Configure Contour Page 209


,

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f the

n

You may use elevation files to control both the Z value and color of contours generated. If the first line of the elevation file has the word “Color”, followed by a list of (Z value, color number) pairsthen for each Z listed, its contour will be drawn in the corre-sponding color.

Example color elevation list file:

color10,120,230,340,4

An elevation file like this would result in the 10 contour being drawn in AutoCAD color # 1 (red), the 20 contour in color # 2 (yellow), the 30 contour in green, and the 40 contour in cyan.

Using color elevation files, you may totally customize you contouring colors and which contours you wish to display with no alterations to the surface itself.

Configure Contour messages

The message on the bottom of the dialogue box may be one ofollowing:

Contouring from file elevations

Used when a valid elevation list file is entered.

File not found

This occurs when an elevation list file is not found.

Contouring from calculated interval

Most common when you have entered a number of levels or aexact contour interval

Page 210 Configure Contour


Configure Drape

The Drape command projects an entity vertically onto a surface (TIN, Grid or TGRD) in memory so that the entity registers at the local Z elevation of that surface. Drape either modifies the z coordinates of selected objects (points, text, blocks), or converts them to 3D polylines (lines, 2D polylines) which follow the shape of the surface as closely as possible, with a given step size.

Configure Drape dialog

Surface for draping

Select the Planar TIN, TIN with Derivatives, Grid or TGRD as the basis for draping. This controls both the surface element objects are draped upon, as well as the surface used by the Track Z command for reporting elevation. Note that if a Drape operation is attempted when the selected surface element is not present in the surface model, nothing will happen.

Planar TIN

Drapes to the planar triangle faces of the TIN. For linear seg-ments of polylines and lines, vertices are only added where the draped object crosses a triangle edge. This is the same as draping on the TIN with derivatives are set to None in Configure Grid.

Configure Drape Page 211


TIN with Derivatives

Uses the Derivatives setting in Configure Grid

Drapes to the mathematical surface represented by the TIN and derivatives. This surface honors all break lines, but also uses cur-vature if the derivatives setting in Configure Grid is set to use 1st or 2nd derivatives. Draped entities such as lines or polylines will have vertices added based upon the Drape Step setting if deriva-tives are used. If derivatives are set to None in Configure Grid, then vertices are only added where a draped object crosses a tri-angle edge. A vertex will always be added where a draped entity crosses a break line.

Grid

Drapes to the surface represented by the Grid. Whether a linear or cubic fit is computed for each grid cell is determined by the setting of Drape order described below. If a surface contains break lines you should not be draping to the grid.

TGRD

Drapes to the surface represented by the planar faces of the trian-gulated grid.

Drape order

When draping to a grid, you may select the nature of the grid cell surface fit. Drape order selects between a linear and cubic fit to the grid cells. Selecting 1st order fits a planar surface to the cell and drapes the entities to it. Selecting 3rd order uses the four points of the cell plus the derivative information to derive a cubic fit describing the cell and drapes to that.

Drape step

The drape step is the length of the segments that the entity will be broken into prior to draping. Drape step applies to lines, polylines, 3D polylines, circles or arcs. Other entities are draped simply by changing the z values of their insertion points.

Page 212 Configure Drape


Additional vertices will always be added where an entity crosses a break line. If you are draping to the Planar TIN (or with Deriv-atives set to None), drape step will be ignored and vertices will only be added where the draped entity crosses a triangle edge. If you choose Auto check box, the step size will be computed as the average of half the width and height of a grid cell. This com-putation is based on the grid cell size setting regardless of whether you are using a TIN, Grid or TGRD to drape onto. Selecting a very small step size will add many vertices, resulting in a much larger drawing file size.

Configure Breaks

Extract Breaks (QSBX) involves segmentation of straight line segments and approximations of curves for accurate modeling.

Configure Breaks dialog

Quicksurf uses an adaptive densification algorithm to densify breaklines only as much as necessary to insure the resulting TIN honor break lines within the given tolerance. This results in the smallest point set possible which still completely describes the surface.

Tolerance

During auto densification, a tolerance is used to control the break line segment length below which segments need not be subdi-vided further. The tolerance is specified in drawing units. This prevents excess computation which is far beyond the accuracy of the model.

Configure Breaks Page 213


Break line curve error

The maximum curve error allowed by Break Extract while seg-menting an arc segment. The curve error e is the maximum dis-tance between an arc segment and its chord.

Break line curve error

The Auto settings work well for most conventional applications. If you are dealing with large radius arcs, you may need to set a discrete curve error value, rather than relying upon the automatic selections.

Configure Extract

Configure Extract dialog box allows you to filter which entities you extract; densify lines and polylines during extraction; deter-mine whether spline or frame points are extracted from polylines which have been smoothed; and limit the maximum number of points extracted.

Configure Extract dialog

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Page 214 Configure Extract


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Densify during extract

Entities such as lines, 2D polylines and 3D polylines may be den-sified during extraction. Selecting Densify during extract uses the Densify step size to incrementally step down the entity and create new surface points in addition to the entity’s vertices. Tis especially useful when additional points may be needed to quately describe the surface.

For example, when creating a new topographic surface by extracting digitized contours, it is common to encounter "flat spots" in some of the drainages in the resulting surface modeThese result from not enough control points defining the bottoof the drainage. These may be eliminated by setting OSNAP to ENDPOINT and snapping a 3D polyline down the drainage fromone contour to the next. By extracting the newly drawn 3D polyline with Merge Extract with Densify during extract enabled, additional points defining the bottom of the drainagewill be added to the surface model. The surface model will noaccurately reflect the topography.

Densify step size

If Densify during extract is enabled the Densify step size is used as the increment to step down the entity being densified. In geral, you should specify a step length for densification, rather than relying on the Auto setting. The Auto setting chooses a stepsize based upon the extents of the model, which may not be appropriate for many cases.

Filter by Entity

Enabling Filter by Entity will invoke the entity filter dialog box each time an extract command is used. This dialog will enablyou to filter the selected objects by entity type prior to extractithem.

Configure Extract Page 215


Entity filter dialog box

The Entity Filter dialog lists all of the entity types available and lets you highlight, then select or delete entity types from the list.

Entity filter dialog before and after selection

Only those entity types remaining on the resulting list will be extracted. A Select button includes entities, a Delete button excludes entities and a Reset button restore the original complete entity list. Press OK when finished.

Filter by Layer

Enabling Filter by Layer allows you to extract only entities on the layer specified in the Layer edit box. This filter may be used together with the other filters. To selectively extract entities from more than one layer, you may repeatedly use Merge Extract and Filter by Layer, specifying different layers each time.

Layer edit box

Enter the layer name to be used with Filter by Layer.

Page 216 Configure Extract


r

Filter by Z

Enabling Filter by Z allows you to extract only points and verti-ces with Z values in the range specified in the Minimum Z and Maximum Z edit boxes. Points and vertices with Z values greater than or equal to the minimum Z and less than or equal to the max-imum Z will be extracted.

Extract only frame points

Select the check box to extract splined polylines at their frame points only, or leave it blank to extract all vertices.

Maximum number of points

Set the maximum number of points allowed to be extracted to the <.> surface. The default is 2,000,000 points.

Extract and User Coordinate Systems

If you want to perform an extraction in a user coordinate system (UCS) which differs from the world coordinate system (WCS), you must manually set the keyword Coorsys to No.

Command: QSOPTKeyword: COORSYSUse world coordinates <Y>: No

Now rotate the drawing into the UCS and extract the data using the Extract to surface (QSX) or Extract Breaks (QSBX) or Merge extract (QSMX) commands. The data will be extracted in the user coordinates. Don’t forget to change back to world coordinateswhen finished.

Chapter 17 has more information on extracting and using UseCoordinate Systems with Quicksurf, see page 327.

Configure Extract Page 217


Configure Boundary

The Configure Boundary dialog controls the criteria for determin-ing when a TIN, TGRD or Grid face is within a boundary.

Configure Boundary

Boundary method

When a grid or TIN is built with a boundary in effect a grid cell or triangle face may overlap the boundary. You may configure which of the following three methods to use for honoring bound-aries.

Center

If the center of the face is within the boundary, draw the face.

Any point

If any vertex of the face is within the boundary, draw the face.

All points

If all of the vertices of the face is within the boundary, draw the face.

There are examples of these settings in Chapter 9: Boundaries.

Boundary tolerance prompt

The boundary tolerance controls how close to a boundary is con-sidered sufficient. The boundary tolerance is computed automat-ically and is generally quite small. Enabling the boundary tolerance prompt causes an additional prompt to be displayed

Page 218 Configure Boundary


which reflects the automatically computed tolerance and allows you to change it if desired. The prompt will appear every time you specify a new boundary.

Configure Units

Different disciplines use different unit conventions for slopes, areas and volumes. Quicksurf allows you to specify how to dis-play measurement of slopes, areas and volumes.

Configure Units dialog

Slope units

Slopes may be specified in degrees, ratio, or in percent. Ratio slope refers to horizontal to vertical ratio (such as 2:1). Percent slope may either be specified as percent slope where 100% slope equals 100 or in decimal percent where a 100% slope equals 1.0.

Area units

Areas by default are returned in square drawing units. You may supply a units conversion factor in the Multiplier box and a text label in the Label box. This will result in all areas being multi-plied by the Multiplier and being followed by the area label, such as 1284.2 sq. ft. or 24.3 acres.

Configure Units Page 219


Volume units

Volumes by default are returned in cubic drawing units, being(X units * Y units * Z units). You may supply a units conver-sion factor in the Multiplier box and a text label in the Label box. This will result in all volumes being multiplied by the Multiplier and being followed by the volume label, such as 32845.3 cu. yds. or 95230.7 barrels.

Configure Camera

The perspective view created by Surface view depends on camera and target positions as well as the height of the camera above the ground and the lens length used on the camera. Configure cam-era allows you to set camera height and lens length.

Camera Configuration dialog box

Within the dialog box you are prompted for camera height and lens length.

Height above surface

The height of the camera above the surface. The default is 10. If the surface is in units of feet, this represents a camera height of ten feet above the surface. You will find that a camera height somewhat taller than a persons eye height works best. Using camera heights of hundreds or thousands produce nice perspec-tive aerial views.

Page 220 Configure Camera


Camera lens

This sets the camera lens length in mm. The default is 30 mm corresponding to a wide angle lens. Lower lens lengths corre-spond to wide angle views and higher lens lengths correspond to telephoto views. Typically lens lengths from 20 - 50 mm work well for topography.

Configure Post

SetPost

The Configure Post dialog box controls text height, rotation, jus-tification and position (offset) of posted values displayed by the Post from memory command. Selecting Configure Post from the menu invokes the following dialog box.

Configure Post dialog box

Position

Nine preset text placements are offered in the upper left corner of the dialog box. These nine selections correspond to top left, top center, top right, center left, center, center right, bottom left, bot-tom center and bottom right. The text offset (relative to the point

Configure Post Page 221


being posted) is a function of the text height being used. One of the nine preset positions may be selected by clicking on one of the nine boxes themselves.

The preset offsets are designed such that subsequent posting of three vertical positions, such as top right, center right and bottom right, will post in an aligned column with no overlap. The center position preset will place the decimal point of the posted value at the position of the data point. Due to this, data posted at the cen-ter position will not necessarily be aligned with other preset posted positions.

Alternatively, you may click on the Pick offset button and graph-ically pick the offset that the posted value will have relative to the point being posted. Discrete text offsets may be entered in the X, Y, and Z edit boxes if desired. Either the preset text offsets, or the user defined offsets are used, not both.

Text Height

Text height in drawing units may be entered in the Height edit box or input graphically by clicking on the Pick height button. Upon clicking on this button the dialog box temporarily disap-pears, allowing you to indicate an height by picking a two points. The distance between the two points becomes the text height and you are returned to the dialog box. If you are unsure of the appro-priate text height, pick it graphically, and the height you picked will be displayed in the Height edit box. You may adjust it fur-ther in the edit box if required.

Text Rotation

The rotation angle of the posted text may be entered in the Rota-tion edit box or input graphically by clicking on the Pick rotation button. Upon clicking on this button the dialog box temporarily disappears, allowing you to indicate a rotation by picking one point which anchors a rubber-band line with which you indicate the desired rotation. The rotation angle you picked is placed into the Rotation edit box. The direction and units of the angle mea-surements are based upon the AutoCAD Units settings.

Page 222 Configure Post


Text Justification

Text justification (left, center or right) only applies if a discrete text offset is specified. These selections are grayed out if one of the nine preset positions is selected. These settings are identical to AutoCAD text justification conventions and justify the text rel-ative to the offset point specified.

Configure ASCII Load

Read ASCII points supports alternate column order and scaling of your input file. You may scale x, y, or z independently during loading using the settings within the Set load options dialog box.

Note: These options only effect the free-form Read ASCII points com-mand, not the Read ASCII table command.

If there are additional columns, or the columns are not in x, y, z order, or you want to scale the data, this command will allow you to define the format. Select the following from the Quicksurf menu:

Configure ASCII point load

This invokes the Read ASCII Points dialog box.

ASCII Load configuration dialog

Configure ASCII Load Page 223


ASCII file

Specify the file containing the ASCII data to be loaded into the results < . > surface. This command does not assume a default extension for the filename; if the filename has one, you must enter it. A full path name is allowed if needed.

Data column position

Specify the three data column position numbers by setting the column numbers that contain the x, y and z data. For example: A file contains four columns representing point number, northing, easting and elevation. The x, y, z column numbers should be set to 3, 2, 4 respectively.

If your ASCII file has missing data (i.e. blank fields), the Read ASCII points command will not load your data as expected. Because Read ASCII points is a free-form parser, when a value is absent, the next valid value on a line is used. In such cases use Read ASCII Table instead, which will tolerate missing data fields.

Scale factors

Next specify any scale factors you wish to use during data load-ing. X, Y and Z values may be scaled independently during loading into surface memory. This is handy for data sets with X and Y in units of feet and Z in units of meters or vice versa.

The options set in this command are preserved in the configura-tion file if you save one. This command only sets the options for data loading by Read ASCII points. The Read ASCII Points com-mand actually loads the points into surface memory.

Spreadsheets, database report generators, application programs, surveying data collectors, laboratory data acquisition systems, word processors and text editors can create ASCII input files suit-able for use with Quicksurf.

Page 224 Configure ASCII Load


Configure Slopes

Setslope

The Intersect Slope and Apply Section commands both require specification of projected slopes. The Intersecting Slope dialog provides for setting the parameters for slope projection.

Slope projection

The Intersecting Slope dialog box is shown on the next page.

Configure Slopes Page 225



Direction

When Quicksurf traverses a polyline path while projecting a slope to intersect a surface, it determines whether the path is above or below the surface and projects the slope down or up as necessary to intersect the surface. This automatic determination is made when the Both selection is selected.

Only in special cases will you need to select the Up or Down but-tons to force the slope direction. For example, if you needed to project a slope up against an embankment or high wall from a control line running in front of and parallel to the wall, you would use the Up option. If the control line was slightly above the sur-face, the Both option would project the line down to the surface, rather than up to the wall.

Both

Projects the slope from the control polyline either up or down as necessary to intersect the surface.

Page 226 Configure Slopes


Down

Forces the slope to be projected down only from the control polyline.

Up

Forces the slope to be projected up only from the control polyline.

Side Control

The slope may be projected on either side or on both sides of the control line. If you were to stand on the first vertex of the control line and look at the second vertex, the right side is to your right and the left side is to your left. You may reverse the vertex order in any line, 2D or 3D polyline using the Swap ends command. The Select point option allows you to graphically pick the desired side without reference to right or left.

Both Sides

Projects slopes from both sides of the control line.

Right Side

Projects slopes from right side only of the control line.

Left Side

Projects slopes from left side only of the control line.

Select Point

Allows you to graphically pick on which side to project the slope.



No Slope Intersection

No slope intersections are calculated. This option is for use with the Apply section command where the resulting 3D polylines from sweeping the section template along a polyline path are desired, but no surface intersection polylines are needed. This would be analogous to extruding the cross section only.

Step Size

This intersect slope step size is different than other step sizes within Quicksurf. The control line is incrementally stepped down during slope projection and the slope is projected until it inter-sects the surface or the edge of the surface model. The point where the projected slope intersects the surface becomes a vertex of the 3D polyline being drawn. The step size represents the maximum allowable distance between adjacent vertices on the resulting 3D polyline (not the control line). If the new vertex from projecting the slope is too far from the previous vertex, the step along the control line is halved and the process is repeated until the distance between adjacent vertices on the 3D polyline being created is less than the specified step size.

The Auto button will attempt to set a reasonable step size, but if you know your site, specify a reasonable step size. Specifying too small a step size results in many more vertices being created than are necessary.

Draw Slope Control Lines

Certain parts of the new surface when using Intersect slope and Apply section require more control than just the slope-surface intersection polyline to adequately describe the resulting geome-try. This occurs most commonly at sharp angles on the control line where a smooth radial sweep at the corner is desired. By default, additional radial lines will be drawn from the control polyline to the slope-surface intersection polyline. If these are extracted as break lines when creating the surface, a smooth cor-ner will result.

Page 228 Configure Slopes


Deselecting the Draw Slope Control Lines check box will cause only the slope-surface intersection polyline to be drawn, with no additional radial lines.

Intersecting Slope

The slope must be specified for both up and down slope projec-tions for both the right and left sides of the control line. If a tran-sition is being done, these slopes must be defined twice, once for either end of the transition segment. In transitions, the slopes may be different at either end of the segment.

Specify the slopes for the right and left sides of the control line (Intersect Slope) or ends of the cross-section template (Apply Section). Different slopes may be specified for projecting up ver-sus projecting down. The current slope unit setting (degrees, per-cent, decimal percent) is indicated at the top of the slope section of the dialog. If a transition is being used, the slopes must be specified for the beginning section of the transition in the left set of boxes and for the ending section of the transition in the right set of boxes.

Transition

Transitions may be linear or smooth splined changes from one section template to the next. The type of transition may be inde-pendently specified for the projected slopes; for the horizontal (XY) positions of the section template vertices; and for the verti-cal (Z) positions of the section template vertices. For each, linear or spline may be selected.

Linear

A linear change between the two section templates is drawn and a linear change between the projected slopes is used.



Spline

A smooth spline curve is fitted between the two section templates to determine the transition geometry. The splines are tangential to the path at either end of a transition. The projected slopes are smoothly varied from the beginning slope to the ending slope for each of the four slope pairs (up and down for both right and left sides).Slope transition

Controls linear or spline transition for the projected slopes.

Horizontal transition

Controls linear or spline transition for the horizontal aspect of the section template vertices. This only affects the XY locations of the interpolated transition between section templates.

Vertical transition

Controls linear or spline transition for the vertical aspect of the section template vertices. This only affects the Z locations of the interpolated transition between section templates.

Configure Section

The Configure Section dialogs control the scaling, labeling and layers used when building 2D profiles and cross sections using the cross-section command.

Configure Section first dialog

Page 230 Configure Section


The first dialog for Configure Section allows you to access either the scaling and labeling settings via the Graph button or the desti-nation layers for the section via the Layers button. An All Defaults check box allows you to reset all section properties to their default values with a single action.

Configure Section Page 231


Graph button

Pressing the Graph button invokes this dialog box.

Configure Section sub dialog

The Graph button invokes this dialog box which controls the components of your 2D sections such as horizontal or vertical multipliers, tick marks, axis labeling and background grid.

Each element of the Graph dialog box is defined below.

Scaling parameters

The 2D sections drawn may be expanded or shrunk in the hori-zontal or vertical axes as specified by the multipliers in the fol-lowing edit boxes.

Horizontal Multiplier

The value specified as Horizontal Multiplier is used to stretch or shrink the cross section along the X axis (horizontally). The default is 1.0, which results in the length of the section equaling



the length of the selected line of section. Choosing a 0.5 would result in the horizontal length of the drawn section being half as long as the selected line of section.

Vertical multiplier

The value specified as Vertical Multiplier is used to stretch or shrink the cross section along the Y axis (vertically). The ratio of the vertical multiplier over the horizontal multiplier is the vertical exaggeration. For example, if the horizontal multiplier is one and the vertical multiplier is three, the drawn 2D cross-section will have a 3:1 vertical exaggeration.

Scaled to fit

If the Scaled to Fit check box is checked, the Horizontal and Ver-tical Multiplier boxes are disabled and you are prompted to specify a window in which to place the section at the time it is created. The section will be scaled to fit in the specified window.

Vertical range

The vertical range allows you to control the maximum and mini-mum vertical values your 2D section includes. These are used when you wish to limit the section to a specific vertical range.

Maximum

This value represents the maximum Z value represented on the 2D cross-section. Any Z values greater than this value are clipped and the section is drawn at this maximum.

Minimum

This value represents the minimum Z value represented on the 2D cross-section. Any Z values less than this value are clipped and the section is drawn at this minimum.



For example, with a set of surfaces that ranges in elevation from 0 to 500, if you want a cross-section covering only the interval from 100 to 200 in elevation, you would set the minimum to 100 and the maximum to 200.

Auto

Selecting this check box will automatically scale your section so the entire range of your data is included on the section. When Auto is selected, the Maximum and Minimum edit boxes are dis-abled.

Graph Annotation

The central part of the Graph dialog box sets the properties of tick marks and background grid on each 2D section. Ticks are the interval marks on the axes. Grid is the background grid drawn behind the section. Each of these have two check boxes and two edit boxes described in groups below.

Ticks

Ticks are the tick marks drawn on each axis of a 2D section. Ticks are drawn as 2D polylines in the current width. They are placed on the layer qs_ticks by default, although you may change this via the Layers button in the Configure Section dialog.

Grid

Grid is the background grid drawn behind the 2D section, similar to graph paper. The grid is drawn as 2D polylines in the current width. The polylines are placed on the layer qs_grid by default, although you may change this via the Layers button in the Config-ure Section dialog.

Numeric Labels

Numeric labels may be placed along the axes of your section. The labeling interval is determined automatically.



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Check Boxes

Checking these boxes control whether or not the element is cre-ated when the section is drawn.

• Ticks• Grid• Numeric Labels

The left-most check box controls whether the item is drawn ornot. For example, checking Ticks, but not Grid, will produce a2D cross-section with axes, tick marks, but no background griThese may be specified in any combination. Axes are alwaysdrawn. For both the Ticks check box and the Grid check box ymay also control the element’s spacing.

X Axis Interval Edit Box

The value in the X Axis Interval box represents the interval in between tick marks and vertical background grid lines drawn along the horizontal axis of the 2D cross-section. The intervaspecified in model space drawing units. Setting X Axis Tick Inter-val to 50 would place tick marks down the X axis every 50 feeSetting the X Axis Grid Interval to 200 would place vertical back-ground grid lines every 200 feet along the X axis.

Y Axis Interval Edit Box

The value in the Y Axis Interval box represents the interval in between tick marks and horizontal background grid lines drawalong the vertical axis of the 2D cross-section. The interval isspecified in model space drawing units. For example, considedrawing in which drawing units are feet and your surface valurange from 2500 to 5000 feet. Setting Y Axis Tick Interval to 100 would place tick marks up the vertical axis every 100 feet. Seting the Y Axis Grid Interval to 500 would place horizontal back-ground grid lines every 500 feet along the vertical axis.



Auto check boxes

Checking the Auto check boxes to the right of the interval edit boxes automatically sets the intervals for the selected items and disables the associated interval edit box.

X origin edit box

By default the X axis labels start at zero at the left end of the sec-tion. If you want to start the labeling at a different value, put that value in the X origin edit box. For example, if your labels are automatically set up for every 500 meters along the horizontal axis, normally they would be 0, 500, 1000, 1500, ... If the X ori-gin were set to 3000, then the labels would start on the left with 3000, 3500, 4000, etc. If you give an irregular X origin, such as 300 , the labeling sequence would proceed 500, 1000, 1500, etc., with the left-most edge (300) not labeled.

Layers Button

The Layers button allows you to change the layers upon which 2D section axes, ticks, and text are placed. The profile polyline is drawn to the current layer. By default the axes and tick marks are placed on the layer QS_AXES, numeric labels are placed on the layer QS_TEXT, and background grid is placed on the layer QS_GRID. The layers are created as needed. The color of all these entities is BYLAYER, so you may set the colors of these lay-ers to create the section coloring of your choice. If you do not want these layers created, you may select the Current radio but-ton to have all axes, ticks, numeric labels and background grid drawn to the current layer.

Current

Draw all axes, ticks, etc. to the current layer.

Named

Draw all axes, ticks, etc. to the layer names described above.

The profile curve itself is always drawn on the current layer.



Configure Surf Ops

The sort order of the surface list displayed by the Surface opera-tions dialog box and the internal computation sequence of all sur-face operations is specified in the following dialog box.

Configure Surface Operations dialog

Surface list sort

The order in which surfaces are listed in the Surface operations dialog box is controlled by the Surface List Sort checkbox. When enabled, surfaces are sorted alphabetically in the list. When dis-abled, surfaces appear in the order in which they where loaded.

Maximize Surface Operations

Mathematical surface operations function by draping the ele-ments of each surface onto the other, then processing the result-ing pairs of Z values. This bi-directional draping is controlled by the Maximize surface operations checkbox. By default, this option is enabled, causing the bi-directional drape. It is a good idea to leave it enabled unless you have a specific reason to do otherwise.

For normal use, leave the Maximize surface operations button enabled.

If you deselect the Maximize surface operations checkbox, a mathematical surface operation drapes the first surface onto the second surface only. This means the resulting parts and the plan view geometry of the results <.> surface is based solely on the geometry of the first surface. If the second surface only has points, then point to point operations only are performed.

Configure Surf Ops Page 237

Consider the example of two surfaces overlying one another: one with 1000 points and a TIN, and the other with 100 points and a TIN. With Maximize disabled, the resulting surface will have different numbers of points depending upon which surface is the first surface in the surface operation. If the first surface is the 1000 point surface, the result will have 1000 points (assuming the surfaces overlap perfectly). If the first surface is the 100 point surface, the result will have 100 points (assuming the surfaces overlap perfectly). The plan geometry of the result reflects the first surface only. By contrast, if Maximize is enabled, the result-ing surface will have 1100 points (assuming no points are coinci-dent in XY).

Please read the Surface Operations chapter for further discussion on the internal mechanics of surface operations.

Page 238 Quicksurf

Chapter 8: Surface Operations

Introduction

Surface operations allow you to perform mathematical calcula-tions between surfaces. Surfaces may be copied, renamed, deleted, and read from or written to disk. Individual parts of one or more surfaces may be selectively cleared. Surface operations allows inspection of detailed surface statistics for any surface.

Surface operations dialog box

DSOP

Surface management and surface algebra are accomplished by invoking the surface operations dialog box from the menu.

Surface Operations

Surface Operations dialog



The surface operations dialog has three main divisions. The sur-face list is in the upper left quadrant, the mathematical controls are in the upper right quadrant with the surface management but-tons beneath them.

Surface list

The surface list displays the names and component parts of the currently defined surfaces. The name of the current surface is displayed above the surface list. The operation of the surface list is the same as the Layer Control dialog box in AutoCAD. Sur-faces in the list may be selected or deselected by picking them with the mouse. When a surface is picked, it is highlighted. Pressing any of the enabled surface management buttons along the bottom of the dialog box will operate on the highlighted sur-faces.

For example, selecting one surface and pressing the Current but-ton makes that surface the current surface. Selecting several sur-faces and pressing the Delete button deletes the selected surfaces from surface memory.

Each line of the surface list contains the surface name and a list of the component parts which currently exist. Some examples:

. P TExisting P TDGProposed PBTD .PBT

The surface name is followed by letters corresponding to existing parts. The letters represent the following parts:

P PointsB BreaksT TIND DerivativesG Grid

Page 240 Surface operations dialog box


Parts listed after the period (such as the .PBT in the Proposed sur-face) represent parts of the triangulated grid (TGRD).

In the list above, the results surface <.> contains points and a TIN. The Existing surface contains points, TIN, derivatives and grid. The Proposed surface contains points, breaks, TIN, deriva-tives, as well as points, breaks and TIN in the TGRD.

Surface management buttons

The surface management buttons operate on the highlighted sur-faces in the surface list. The buttons may be grayed-out if unavailable for the selected surface(s). For example, if more than one surface is selected, the Current button is unavailable because you may only have one current surface.

Select All

Highlights all surfaces in the surface list.

Clear All

Clears the highlighted selections in the surface list. This is sim-ply de-selecting any highlighted surfaces in the list. This com-mand does not affect the contents of any surface.

Current

Sets the current surface. The current surface is offered as the default surface name for any command involving a surface. The Current button is only available when one surface is selected from the surface list.

Surface operations dialog box Page 241


Read QSB

SOP Read

Invokes the standard file dialog box to read a Quicksurf binary QSB file which has been previously saved. QSB files are created by the Write QSB command or the Load ASCII Table command (QSML). All of the surfaces in the QSB file are loaded into sur-face memory. Any existing surface in memory with the same name as a surface in the file is overwritten without comment. If you wish to load only selected surfaces from the file, rather than all surfaces, use the SOP Read command from the keyboard, which will prompt you surface by surface for which surfaces to load.

Write QSB

SOP Write

Writes selected surfaces to a binary QSB disk file. The high-lighted surfaces will be written. Write QSB invokes the standard file dialog box to write a Quicksurf binary QSB file. The QSB file has a file extension of .QSB. A QSB file is a very efficient way to store surface information. All surface parts and descrip-tions are stored in the file, but boundary and window information (if any) are not. Reading a QSB file written with this command restores all of the written surfaces to surface memory.

Clear Parts

SOP Clear

Invokes the Clear Parts dialog box, allowing you to remove any or all parts from the selected surfaces. The Clear Parts dialog lists all of the parts of the selected surface(s) and allows you to pick which ones are to be removed. In this way specific parts, such as the TIN, Grid or TGRD, may be removed from a surface.



Copy

SOP Copy

Copies the contents of a selected surface into another surface. With the surface to be copied selected, press Copy and a small dialog pops up allowing you to enter the new surface name. If the new surface does not exist, one will be created under the name supplied. If it does exist, its contents will be replaced by the new contents.

Delete

SOP Delete

Deletes the highlighted surfaces from memory. Deleting the results <.> surface will produce an empty <.> surface; deleting a named surface will eliminate it completely. AutoCAD drawing entities that have been generated with the Draw option will not be affected.

Detailed

Displays the detailed surface information for one surface, includ-ing surface description, associated AutoCAD layer, surface method, and surface statistics including number of points; mini-mum and maximum of X, Y, Z, and slopes; plan and surface area; and volume. The Detailed button is enabled only when a single surface is highlighted in the surface list.

If more than 10,000 points are in a surface, you will be given a chance to skip area and volume statistics calcu-lation.

There may be a pause when invoking the detailed listing while Quicksurf calculates the area and volume statistics. The areas and volumes reported will be in square drawing units or cubic draw-ing units unless a user-specified units have been defined in the Configure Units dialog box.

Pressing the Detailed button invokes the following dialog box.



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Surface Information dialog

Within the detailed surface information dialog, you may change the name of a surface, add a detailed description for the surface, or create a link between a surface in surface memory and a layer in the AutoCAD drawing. The dialog box show above has all parts shown for purposes of illustration, normally a TGRD and Grid don’t co-exist in the same surface.

Surface Edit Box

SOP REName

The surface edit box displays the surface name. You may chathe name of a surface by altering the name in the edit box.



Description Edit Box

SOP DESc

You may enter a surface description (up to 100 characters) which will be carried for the rest of the drawing session and included in any QSB file you may save. The description field for the results surface is automatically filled by the surface operation which cre-ated it with a description of the operation performed.

Layer Edit Box

SOP LAyer

Associates an AutoCAD drawing layer with a Quicksurf sur-face. Any Quicksurf-generated drawing entity related to this sur-face will be placed on this layer. When you select the Draw option from the Points, Breaks, TIN, TGRD or Grid commands, the entities drawn will be placed on the designated layer.

This operation overrides the current drawing layer as set by the AutoCAD Layer command. If no layer is specified, Quicksurf always draws to the current layer.

Surface statistics

Statistical information on each surface part is displayed in the surface information dialog box. Number of points, minimum and maximum values for X, Y, Z, and slopes are displayed. Plan area, surface area and volumes are computed for TIN, Grid and TGRD parts. All computations encompass the entire surface.

Note that the memory used by the surface is displayed at the lower right of the dialog box. Deleting surfaces frees memory and makes it available to AutoCAD and Quicksurf.



Mathematical operation controls

Mathematical operations on or between surfaces may be per-formed using the Surface Operations section located in the upper right portion of the dialog box. A wide variety of operations may be performed on one surface, between one surface and a constant, or between two surfaces. The result of any surface operation is placed in the results <.> surface, sometimes called the "dot" sur-face.

The dialog layout contains entries for a 1st Surface, an Operator, and optionally a 2nd Surface and a Constant.

These form the components of an algebraic expression which is executed upon pressing the Run Operation button.

For example, if we wanted to calculate the difference between two surfaces, Proposed and Existing, to determine cut and fill, the 1st Surface would be Proposed, the operator would be - (minus), and the 2nd surface would be Existing. Pressing the Run Opera-tion button would place (Proposed - Existing) into the results <.> surface.

The 1st Surface and 2nd Surface selections consist of pop-down lists of the surfaces currently in surface memory. The Operator pop-down list contains all available surface operations. The Con-stant selection consists of a checkbox, to select using a constant, and an edit box to specify the value of the constant. The Constant and 2nd Surface selections may be grayed-out if the selected Operator only functions on one surface (such as SIN or Absolute Slope).

When the Run Operation button is pressed, the mathematical operation is computed and the results are placed in the <.> sur-face, replacing any pre-existing contents. If you need to save the contents of a pre-existing <.> surface, use the Copy button to copy the <.> surface to a named surface. A prompt string in the lower left corner of the dialog box reports when the operation is completed. When the computation is complete, you are left in the



Surface Operations dialog box, so you may compute chain calcu-lations. The results surface itself may be specified as either the 1st or 2nd surface in any calculation, but realize that the result will replace the <.> surface after the operation is complete.

The behavior of surface operations is affected by the setting in the Configure Surface Operations dialog, described in the Configur-ing Quicksurf chapter. For the most accurate result, the Maxi-mize Surface Operations checkbox should be selected within this configuration. This is the default setting.

Surface management functions

Most surface management functions are accomplished via the dialog box, but these are also accessible via the SOP keyboard command. The keyboard commands contain some functions not available directly in the dialog box. The keyboard SOP com-mands are summarized below. The minimum characters needed to invoke the command are capitalized.

SOP CLear

Surface/’*’ for all <.>: Enter surface name or * to delete all surfacesALL/Points/TIN/Derivatives/Grid/tgRid: select parts to clear

Clears parts of surfaces from memory. The first option selects the surfaces to be operated on and the second selects the parts to be cleared: points, TIN, derivatives, grid, TGRD or all parts. More than one part may be cleared at once, for example, answering DG to the second prompt will clear the derivatives and grid.

Clearing all parts of all surfaces is the same as deleting all sur-faces.



SOP DELete

Surface/’*’ for all <.>: Enter surface name or * to delete all surfaces

Deletes surfaces from memory. The results <.> surface will become an empty surface, or a named surface will disappear com-pletely. AutoCAD drawing entities that have been previously generated with the Draw option will not be affected.

SOP COPy

Surface <.>: Enter surface name to copyTo: Enter destination surface name

The specified named surface is copied to the specified destination surface.

SOP MOve

Surface <.>: Enter surface name to moveTo: Enter destination surface name

Moves the contents of a surface into another surface. Similar to Copy, but destroys the source surface instead of duplicating it. The same net effect may be achieved with Rename, except that Rename will fail if the destination surface name already exists or the source surface is the current surface.

SOP REName

Surface <.>: Enter surface name to renameTo: Enter destination surface name

Changes the name of a named surface to the specified name. The results <.> surface cannot be renamed, and the new name must not already exist.



SOP LOad

Surface <.>: Enter surface name to copy to the <.> surface

Copies a named surface to the results <.> surface, replacing the pre-existing contents. SOP Load is simply copying surfaces within memory, it is not reading surfaces from disk. Disk opera-tions are handled by the SOP Read and SOP Write commands.

SOP SAve

Surface <.>: Enter destination surface name to copy the <.> surface to

Copies the results <.> surface to a named surface, replacing the pre-existing contents. SOP Save is simply copying surfaces within memory, it is not saving surfaces to disk. Disk operations are handled by the SOP Read and SOP Write commands.

SOP DESc

You may enter a surface description (up to 100 characters) which will be carried for the rest of the drawing session and included in any QSB file you save. The description field for the results sur-face is automatically filled in by surface operations. It will con-tain a description of the operation, such as Existing - Proposed.

SOP LAyer

Associates an AutoCAD drawing layer with a Quicksurf sur-face. Any Quicksurf generated drawing entity related to this sur-face will be placed on this layer. When you select the Draw option from the Points, Breaks, TIN, TGRD or Grid commands, the entities draw will be placed on the designated layer.



This operation overrides the current drawing layer as set by the AutoCAD Layer command. When you generate drawing entities with Quicksurf, and the surface associated with them has a desig-nated layer, they will appear on that layer; otherwise they will appear on the current layer.

SOP LIst

Displays a listing of surfaces currently in surface memory to the AutoCAD text screen and flips the display to the text screen. The <.> surface will appear first, followed by named surfaces. The parts are listed to the right of the surface name. If a TGRD is present the surface listing consists of two lines, the second line representing the parts of the TGRD. The number of points, the grid cell count, the grid method and a description are also listed. Pressing return will return you to the graphics screen.

Surface modification operations

Grid geometry operations

These functions modify the size, count, and geographic limits of grid cells. These functions both change the settings as seen in the Configure Grid dialog box, then delete and recalculate the existing grid of the current surface using the new parameters.

The difference between using these functions and resetting the parameters in the Configure Grid dialog is that these functions delete and recalculate the grid, whereas changing the Configure Grid setting only affect grids built subsequently.

Page 250 Surface modification operations


Cell size

SOP CSize

Redefines the grid cell size for the current surface and subsequent gridding operations. This is the easiest way to resize a grid once it has been generated. Your other option is to clear the grid from the surface and manually set a grid cell size and recalculate it.

Surface options -> Cell Size

Current cell size is ## X ## (cell size in x, y)Horizontal cell size <default>: valueVertical cell size <default>: value

Set the horizontal and vertical cell sizes at the prompts or press enter to accept the defaults. The cell size represents the X and Y dimensions of one individual cell. Remember, this sets the cell size permanently until you reset it to Auto (0.0) or to a new size. If Cell Size is defined, Cell Count and Cell Factor are ignored. Cell size may also be set from Configure Grid dialog box.

Cell count

SOP CCount

Redefines the number of grid cells for the current surface and subsequent gridding operations if cell size is not defined. Cell Count is only used if Cell Size is set to Auto (0.0). If a specific cell size is specified, then this command has no effect. The order of precedence in determining cell configuration is cell size, then cell count, then cell factor.

Surface options -> Cell Count

Current cell count is ## X ## (cell count in x, y)Horizontal cell count <default>: valueVertical cell count <default>: value

This may also be set from Configure Grid dialog box.

Surface modification operations Page 251


Set the horizontal and vertical cell counts at the prompts or press enter to accept the defaults. The cell count controls the number cells in the X and Y dimensions of the entire grid. For example, a horizontal cell count of 40 and a vertical cell count of 30 will pro-duce a grid with 1200 cells.

Remember that this cell count setting remains in effect until you reset it to a new value or Auto (0).

Cell factor

SOP CFactor

Sets the cell factor, which is used for automatic determination of cell count when Cell Size and Cell Count are not defined.

SOP CFactor

Current cell factor is 4.0 New cell factor <4.0>: value

This may also be set from Configure Grid dialog box.

When both the size and number of grid cells are not specified, Quicksurf will set the number of grid cells to this factor times the number of points, then adjust it up or down if necessary to bring it within the CellMin and CellMax settings.

This command will set the cell factor variable to the specified value and set the cell size and count variables to Auto.

Window

SOP WINdow

Redefines the geographic window within which grid calculations will be performed. This command only effects the grid, not the TGRD.



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Surface options -> Window

[Window is set to max...]Define working window for current surface...Select first corner/Max: enter point or enter for Max window[Select second corner]: enter point

By default, the window is set to Max, the smallest rectangle that contains all the control points. If this is in effect, you will receive the message “Window is set to max...” followed by the “Define win-dow” prompt. If a smaller window is in effect, you will receive only the “Define window” prompt. Enter the two points defining the rectangular window with the pointing device (or type the Xand Y coordinates) or press enter to set the window to Max. Ifyou entered a point, you will be prompted for the lower right point.

This operation only works when in plan view. The grid is recaculated only within the specified window.

You can get into trouble by forgetting you have a window set.

Please note this command changes the window globally for agrid surfaces generated subsequently. It is a good idea to resewindow to Max once your are finished with a particular surfaceIf the grid window is set improperly you may receive the Error: grid undefined message or produce no contours due to the fact thewindow and the surface data do not overlap.

The window option is useful for editing multiple small areas oflarge map. The grid is only calculated for a small area, allowiniterations between edits to be short. When finished, set windowMax and regenerate the entire grid.



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Surface modification operations

Set

SOP SET

Creates a surface consisting of the X, Y locations of the first sur-face and the corresponding Z elevations of the second surface or constant. The result will contain data for the area in which the two surfaces overlap. If a constant is specified, instead of a sec-ond surface, the plan geometry will be identical to the first sur-face.

If the selected surfaces does not overlap you will get the reply “No resulting surface”. Otherwise the elevations in the first surface will be set as requested. This is the easy way to create aface of constant Z with a grid cell size the same as another surface. The first surface selected controls the grid cell size athe second surface (or constant) controls the elevation.

Merge

SOP MErge

Merge will added the contents of two surfaces together in the results surface. This will filter the data and not include any datpoints from the second surface which also exactly occurs in thfirst surface. The data areas may overlap or not match at all. Tresultant surface will contain only points and breaks.

Splice

SOP SPlice

Splice will copy the data from the first surface and add the nonoverlapping portion of data in the second surface. The convepolygon containing all of the points of the first surface outlinesthe area to be spliced. The resultant surface will contain onlypoints and breaks.



Z rotation

SOP ZRot

Rotates the first surface about a specified center of rotation by a specified angle of rotation. The X, Y location of the center of rotation and the rotation angle (in degrees) is prompted for in a small pop-up dialog box. The surface is rotated about the Z axis by the angle specified in degrees. A positive angle rotates counter-clockwise as viewed from above. The result is placed in the results <.> surface.

Translate X

SOP XTrans

Translates the first surface in the X dimension by the Constant value. The result is placed in the results <.> surface.

Translate Y

SOP YTrans

Translates the first surface in the Y dimension by the Constant value. The result is placed in the results <.> surface.

Scale X

SOP XSCale

Scales the X dimension of the first surface by the Constant value. The result is placed in the results <.> surface.

Scale Y

SOP YSCale

Scales the Y dimension of the first surface by the Constant value. The result is placed in the results <.> surface.



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Mathematical surface operations

Understanding surface operations

These operations, forming the heart of the surface operations sys-tem, perform mathematical operations on one or two surfaces, generate a new surface, and write it into the results <.> surface. The key to surface operation between surfaces is knowing what is actually happening when an operation is performed. We will cover two distinctly different areas of surface operations:

• Operations between surfaces containing points only

• Operations between surfaces containing Points and one omore other parts such as a Breaks, TIN, Grid or TGRD

Point to Point operations

All operations between surfaces containing only points performbasic point to point arithmetic. Only points sharing exactly the same XY coordinate in both surfaces will have the mathematicaoperation performed. Points that do not have matching XY codinates will not be operated upon. Thus the resulting surface only contain values for the points which existed in both surfacand were exactly coincident in X and Y. This special case is commonly used for stacked geologic surfaces whose definingpoints originated in vertical wellbores.

Surface operations between mixed surfaces

Surface operations between two surfaces containing differentparts produce a results <.> surface which may contain a TIN, Grid, or TGRD in addition to Points. With the Maximize Sur-face Operations option selected (discussed below), any surfacpart existing in either input surface will be created in the resulsurface.

Page 256 Mathematical surface operations


In the point to point surface operations described above, only points which were coincident in X and Y were used in the calcu-lation. This meant that for each pair of coincident points, we had defined Z values in both surfaces and performed the operation. In the general case we will have two surfaces with some combina-tion of points, breaks, TIN, TGRD and Grids that will overlap each other. The elements of the two surfaces most likely will not be registered to each other. Quicksurf must determine a Z value for both input surfaces at each point within the area where the surfaces overlap.

Surface operations internally rely upon the drape function, which in its most basic form solves for the Z value of a surface given an X, Y coordinate. Surface operations must drape the elements of the first surface onto the second surface, then drape the elements of the second surface onto the first surface. In this way, pairs of Z values will be determined for each point or vertex in either sur-face within the area where the two surfaces overlap. The surface operation is then computed on each resulting Z pair and a new Z value is placed in the results surface for that location.

When a point is draped onto a surface, surface operations must choose which representation of the surface to use. The choices include draping to the planar faces of the TIN, TGRD or Grid, or draping to the TIN using curvature (derivatives).

The following hierarchy determines which part is draped upon:

1. TIN using Derivatives.2. TGRD, if present and TIN is absent.3. Grid, if present and TIN is absent.4. Point to point operations only, if only points are present.

If choice #1 (TIN and Derivatives) is used, the Derivative order setting from the Configure Grid dialog is used. The setting choices for Derivative order include None (uses the planar faces of the TIN), 1st (continuous slope) or 2nd (continuous curvature).

Mathematical surface operations Page 257


Derivatives are created if necessary. This drapes on the actual mathematical surface, rather than a sampling of it such as the grid or TGRD.

Draping to the grid is only used in the special case where the grid has been modified (for example by MIN or MAX) such that the grid does not necessarily follow the same surface as the surface described by the TIN and Derivatives. Any surface operation which causes this condition deletes the TIN, so the hierarchy above always functions correctly.

Maximize Surface Operations

As described above, surface operations function by draping the elements of each surface onto the other, then processing the resulting pairs of Z values. This bi-directional draping is con-trolled by the Maximize surface operations button in the Con-figure Surface Operations dialog. By default, this option is enabled, causing the bi-directional drape. It is a good idea to leave it enabled unless you have a specific reason to do other-wise.

If you deselect the Maximize surface operations button, a sur-face operation drapes the first surface onto the second surface only. This means the resulting parts and the plan view geometry of the results <.> surface is based solely on the geometry of the first surface. If the second surface only has points, then point to point operations only are performed.

For normal use, leave the Maximize surface operations button enabled.

Consider the example of two surfaces overlying one another: one with 1000 points and a TIN, and the other with 100 points and a TIN. With Maximize disabled, the resulting surface will have different numbers of points depending upon which surface is the first surface in the surface operation. If the first surface is the 1000 point surface, the result will have 1000 points (assuming the surfaces overlap perfectly). If the first surface is the 100 point surface, the result will have 100 points (assuming the surfaces overlap perfectly). The plan geometry of the result reflects the



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first surface only. By contrast, if Maximize is enabled, the result-ing surface will have 1100 points (assuming no points are coinci-dent in XY).

Grid to Grid operations

Registered Grids

If the grids are perfectly registered, surface operations will not perform a drape, it simply will do the operation between corre-sponding grid nodes, speeding up the operation significantly. The results surface will contain a grid. Each point of a the first surface is compared to every point in the second surface to deter-mine if they are exactly coincident. For large point sets this com-parison can be time consuming. If you are performing grid to grid operations on large data sets and do not need the point infor-mation, clear the points from the first surface prior to operation for vastly greater speed.

Non-Registered Grids

Operations between two gridded surfaces involves both grid sur-face’s grid nodes and points being draped to the other and sofor a Z value. The results surface will contain points at the X,Ylocation of both sets of original grid nodes, as well as the origipoints. A TIN and Grid will then be computed for the result. Ithis case, the grid is not a result of grid to grid math, rather a regridding of the new surface. This assumes Maximize Surface Operations is enabled in the Configure Surface Operations dia-log.

If Maximize Surface Operations is not enabled, then the resultssurface will contain a grid with the plan view geometry of the firssurface. In this case only the points and grid nodes of the firssurface are draped upon the second surface with the resultingpoint set and grid placed in the results surface. The resulting gsurface will cover the largest rectangle for which grid nodes wedefined by the after draping to the second surface.



Mathematical surface operators

These operators calculate new surface Z values and place the result in the results <.> surface. The X, Y geometry of the result is dependent upon the geometry of the two input surfaces.

Addition (+)

SOP +

Calculates the sum of the first surface and the second surface (or constant). The result is placed in the <.> surface.

Subtraction (-)

SOP -

Calculates the first surface minus the second surface (or con-stant). The result is placed in the <.> surface. Commonly used for cut / fill or thickness maps.

Multiplication (*)

SOP *

Calculates the product of the first surface and the second surface (or constant). The result is placed in the <.> surface.

Commonly used to exaggerate the relief of a relatively flat sur-face for emphasis. A surface may also be inverted by multiplying by a constant value of -1.

Division (/)

SOP /

Calculates the quotient of the first surface divided by the second surface (or constant). The result is placed in the <.> surface.



Remainder (%)

SOP %

Calculates the modulus (remainder) of the first surface divided by the second surface (or constant). The result is placed in the <.> surface. Usually results in a surface with very little relief.

Minimum

SOP MIN

Calculates the minimum of the z values of the first surface and the second surface (or constant). The result is placed in the <.> surface.

A common use of this command is to separate cut and fill quanti-ties for volume measurement or contouring. For example, calcu-lating the minimum of an (Proposed - Existing) surface and a constant of zero, would yield a planar surface with depressions representing cut depths.

If the surface contains only points, the result will be points with their z values modified as appropriate. A TIN, Grid or TGRD will be modified to conform to the minimum constraint. Realize that the Min and Max functions work on all parts of the surface. A consequence of this is that the result may be order dependent in certain cases. Starting with points only, gridding a surface then taking the minimum will produce a different grid than taking the minimum then gridding the result, due to differences in slopes prior to gridding.

When the Max and Min functions are used on a TGRD or Grid, individual grid nodes may have their elevations altered. This cre-ates a condition such that the mathematical surface described by the TIN with derivatives may disagree with the modified TGRD or grid surface nodes. To avoid ambiguity, the TIN is deleted by these two surface operations. This forces the modified TGRD or grid to be used.



The Max and Min functions force TGRD and Grid nodes to exactly the value requested. This will cause contours drawn at the clipped elevation to be angular. Adjusting the clipping eleva-tion to just above or below the highest or lowest contour will pro-duce smooth contours. Instead of these functions, you may alternatively specify a specific list of elevations for contouring using the elevation file option within the Configure Contours dia-log box.

Maximum

SOP MAX

Calculates the maximum of the z values of the first surface and the second surface (or constant). The result is placed in the <.> surface. Please read the surface operations Minimum description above which describes special considerations when using Min and Max.

A common use of this command is to separate cut and fill quanti-ties for volume measurement or contouring. For example, calcu-lating the maximum of an (Proposed - Existing) surface and a constant of zero, would yield a planar surface with elevations rep-resenting fill depths.

Absolute value

Sop ABs

Calculates the absolute value of the first surface. This operation simply converts negative to positive values, leaving positive val-ues unchanged. The result is placed in the <.> surface.

Square root

SOP SQrt

Calculates the square root of the first surface. The result is placed in the <.> surface.



Exponential

SOP EXP

Calculates the exponential of the first surface. The result is placed in the <.> surface.

This can be extremely useful when used in conjunction with the natural log (LN) command. When working with concentration data sets which have extreme behavior you may elect to take the natural log of the surface prior to modeling and normalize back with the Exponent function afterwards. This causes the slopes to be calculated in logarithmic space which has much better slope behavior.

Natural Log

SOP LN

Calculates the natural log (ln z) of the first surface. The result is placed in the <.> surface.

This command is extremely helpful when dealing with data that has spikes. When working with concentration data sets which have extreme behavior you may elect to take the natural log of the surface prior to modeling and normalize back with the Exponent function afterwards. This causes the slopes to be calculated in logarithmic space which has much better slope behavior.

Common Log

SOP LOG

Calculates the base 10 common log (log z) of the first surface. The result is placed in the <.> surface.

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Power of 10

SOP POWER10

Calculates for the first surface. This is the inverse of the Log function. The result is placed in the <.> surface.

SIne

SOP SIn

Calculates the trigonometric sine (sin z) of the first surface. The result is placed in the <.> surface.

Cosine

SOP COS

Calculates the trigonometric cosine (cos z) of the first surface. The result is placed in the <.> surface.

Arctangent

SOP ATan

Calculates the trigonometric arctangent (atan z) of the first sur-face (in degrees). The result is placed in the <.> surface.

Floor

SOP FLoor

Rounds all z values in the first surface downward to the next lower (or equal) integer. The result is placed in the <.> surface.

Reciprocal

SOP RECip

Calculates the reciprocal (1/z) of the first surface. The result is placed in the <.> surface.

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Absolute slope

SOP ASLope

Calculates the absolute slope of the first surface in decimal per-cent. The result is placed in the <.> surface. The absolute slope

is defined by .

This operation requires a grid to be present in the current surface. If no grid is present it will return the message “No grid” and teminate.

The absolute slope function produces a surface with a Z valuerepresenting slope in decimal percent (1.0 equals 45 degreesContouring this slope surface produces contours of equal slop

Invoking this command twice will produce a surface of secondderivatives, which is a representation of surface curvature. Sua surface is useful in geology for locating areas of a surface wthe highest curvature, which may correspond to the most highfractured areas.

Degree slope

SOP DSLope

Calculates the absolute slope of the first surface in degrees. Tcommand is the same as the Absolute slope operation (abovebut the result is expressed in degrees rather than percent. Thresult is placed in the <.> surface. The absolute slope is defin

by the arctangent of .

This operation requires a grid to be present in the current surfaIf no grid is present it will return the message “No grid” and teminate. Contouring this slope surface produces contours of eqslope. The slope analysis chapter has more information on usthe absolute slope surface operation.

x∂∂z

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XSlope

SOP XSLope

Calculates the X component of the slope of the first surface. The

result is placed in the <.> surface. X slope is defined by .

This operation requires a grid to be present in the current surface. If no grid is present it will return the message “No grid” and teminate.

YSlope

SOP YSLope

Calculates the Y component of the slope of the first surface. T

result is placed in the <.> surface. Y slope is defined by .

This operation requires a grid to be present in the current surfaIf no grid is present it will return the message “No grid” and teminate.

Trend

SOP TRend

Calculates a polynomial trend surface of the first surface baseupon the current settings for the Trend method in the Configure Grid dialog box. The resulting trend surface will contain only points and a grid. The result is placed in the <.> surface. SeeConfigure Grid section for information on trend theory.

x∂∂z

y∂∂z



Residual

SOP RESidual

Calculates a trend surface of the first surface based upon the cur-rent settings for Trend method, then subtracts the trend surface from the original surface to produce a residual surface. The resid-ual surface is placed in the <.> surface.

The residual surface represents the local high and low areas of the original surface relative to the trend surface.

The Residual operation combines the two steps of creating the trend surface and subtracting it from the original into one opera-tion. The trend surface used internally is not saved, but may be re-created with the trend surface operation.


Quicksurf

d-a,

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Chapter 9: Boundaries

You may limit the area in which Points, Breaks, TINs, TGRDs, Grids, Contours or draped objects are displayed by specifying one or more closed polylines as boundaries with the Set Bound-ary command. The boundaries may be nested. Boundaries are very useful for presentation purposes and volumetric limitations.

Boundary smart commands

Set Boundary defines an arbitrary boundary defining the area within which Quicksurf will display a surface. Boundaries affect both draw and show operations. Using boundaries only affects the display of a surface, the surface itself is not modified by the presence of boundaries. The following boundary-smart com-mands will honor any boundaries in effect:

• Points• Breaks• TIN• Grid• Triangulated Grid (TGRD)• Contour• Drape• Post from memory• Surface region

A word of warning: Boundaries limit the display of Quicksurf objects to within the boundary. If you forget and leave a bounary set in one area of your model, then move to a different areyou may not be able to display contours, etc. If you attempt todisplay parts of a surface and don’t see anything, it may be duhaving set a boundary which does not overlap the surface.

Boundary smart commands Page 269


Establishing boundaries

Boundaries may be extracted from closed 2D or 3D polylines in the drawing or read from ASCII boundary files. Boundaries may be read from and written to disk files with the Read ASCII Boundaries and Write ASCII Boundaries commands as described in the Command reference chapter.

Once a boundary has been selected, it is independent of the draw-ing entity used to create it. The parent polyline may be erased or frozen with no effect on the boundary.

Prior to running the Set boundary command, the boundary must exist as one or more drawn AutoCAD entities. They should be either 3D or 2D closed polylines. Although the Set boundary command will close polylines which are not closed, the result may not be identical to the closed polyline if arc segments are involved. Try to always use closed polylines as boundaries. Once a boundary has been selected it stays in effect for the remainder of the drawing session, even if the polyline it was cre-ated from is erased. Boundaries may be temporarily disabled or permanently deleted with the Set boundary command.

A circle selected as a boundary is ignored completely if drawn as a circle entity and not a polyline; a closed circular polyline arc will be accepted as a circular boundary.

Page 270 Establishing boundaries


Nested boundaries

You may selectively include and exclude regions by drawing nested closed polylines representing boundaries. The surface will be shown or drawn in any area that is enclosed by an odd number of boundaries, and not in any area enclosed by an even number of boundaries.

Nested Boundaries

Nested boundaries are used extensively in site planning and vol-ume calculations. Nested boundaries also may be used to prevent dense contours from overlapping map annotations.

Boundaries and surface displays

When a grid or TIN is displayed with a boundary in effect, a grid cell or triangle face may overlap the boundary. The Configure boundary dialog provides for three options to determine whether or not to show or draw a grid cell or TIN triangle. These options are center, any point or all points.

Nested boundaries Page 271


The center option displays the grid cell or triangle if the center of the element is within the boundary. The any point option displays the grid cell or triangle if any vertex of the element is within the boundary. The all points option displays the grid cell or triangle if all vertices of the element is within the boundary.

Boundaries and TIN displays

Note that grid cells and triangles are either displayed completely or not at all; they are not clipped at the boundary. If you want the TIN to follow the boundary exactly, extract the boundary polyline as both a break line and a boundary. This will force the triangulation to follow the boundary exactly, resulting in no trian-gles crossing the boundary. The Surface region command does this automatically.

Page 272 Boundaries and surface displays

Chapter 10: Break lines

Break lines represent discontinuities in the slope of a surface. Examples of breaks are the edges of ditches, walls and curbs in civil engineering and faults in geology. Whereas a surface with-out breaks maintains continuous slope and curvature throughout, a surface with breaks may have abrupt changes in slope at edges where the surface crosses break lines.

Creating break lines

Break line data may be loaded to surface memory by the follow-ing commands:

Extract Breaks (QSBX)Read ASCII Breaks (QSBL)Read QSB File

The Extract Breaks command extracts break data from AutoCAD drawing entities such as 2D and 3D polylines. Read ASCII Breaks reads break data from disk files, such as survey data. Read QSB reads break data from Quicksurf surfaces previously stored to disk.

Extract breaks extracts break line data from drawing entities and adds them incrementally to the results < . > surface. The follow-ing entity types are extracted and adaptively densified by Extract Breaks:

Line2D or 3D PolylinesArcCircle3D Face Edges become breaksTraceSolid Non-extruded edges become breaks

Creating break lines Page 273


All other entity types are ignored. The result of Extract Breaks is dependent upon the settings in the Configure Extract dialog

The Extract breaks command is normally used after Extract to surface or Merge extract have already put points into the <.> sur-face, but may be used by itself if the surface is composed only of break lines with no points.

If the surface is created from data in the drawing, the typical workflow sequence consists of :

Extract to surface (QSX) Creates a new surface just with pointsExtract breaks (QSMX) Incrementally adds breaksTIN or TGRD Use a TIN or TGRD model with breaks

Extract breaks may be used several times sequentially and each new set of breaks will be incrementally added to the surface and resolved. Break line resolution is faster when Extract breaks is run once on all break lines, rather than once for each break line.

If the surface is created from data from an ASCII file, the typical workflow sequence consists of :

Read ASCII Table (QSML) Creates a new surface just with pointsRead ASCII Breaks(QSBL) Incrementally adds breaksTIN or TGRD Use a TIN or TGRD model with breaks

Adaptive densification

3D polylines are the most common entities used for break lines. Break lines must be densified by Quicksurf such that any subse-quent TIN honors breaks exactly. New points are interpolated along polyline segments as needed and are added to the surface. The goal in break line densification is to add the minimum num-ber of new points to the surface which completely describe the break line geometry within the specified tolerance.

Page 274 Adaptive densification


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This version of Quicksurf introduces adaptive densification, which densifies break lines with a variable break step and pro-duces a much smaller point set than the fixed break step densifi-cation of earlier versions. The earlier approach using a fixed break step resulted in large surface models. If part of the surface model required a small break step, it was applied to the entire model.

Repeated triangulation during densification is normal on complex models.

Adaptive densification uses a variable break step, which keeps the model as small as possible. This results in faster execution of all subsequent surface commands. The adaptive densification used within Extract breaks automatically produces a TIN in the results surface. The densification procedure may triangulate the surface many times as it converges on the most efficient densified TIN.

Resolving break lines

Extract Breaks resolves contradictory or redundant data between adjoining break lines or between break lines and pre-existing points in the following sequence:

• Break line defining points coinciding with pre-existing pointare dropped.

• Stacked or doubly selected points are dropped.

• Break line intersections are resolved to a single new point

• Adaptive densification retriangulates and adds new points

• A final TIN is created honoring the new break lines.

Stacked data points (multiple control points at a given x,y location) along break lines are dropped. Quicksurf resolves stackedata by arbitrarily deleting points from a stack until there is onone. Break lines made up of multiple polylines with common endpoints are treated as break line intersections, slowing procing.

Resolving break lines Page 275


Intersecting break lines

When Quicksurf processes a single break line, the elevation of the break line itself furnishes the elevation of all densified surface points along it. This produces a potential ambiguity when two break lines intersect over a common x,y point, yet differ in eleva-tion. Intersecting break lines are representing the same surface, therefore the elevation must be the same at any break line inter-section. Quicksurf resolves this by setting the elevation of the surface to the mean of the elevation values on the two lines. This feature resolves small measurement and interpolation errors.

To resolve crossing break lines, Quicksurf must compare every segment of every break line against every other segment. As the number of break lines increases, the computation time increases dramatically. Only extract entities as break lines if they represent an edge with an abrupt change in slope. If the entity lies in the surface, but is in an area of continuous curvature, extract it with Extract to surface rather than Extract breaks. This will speed pro-cessing.

Always use the TIN or Triangulated Grid command, not the Grid command when modeling a surface containing break lines, as a TIN and TGRD honor break lines exactly and Grid only approxi-mates break lines. Likewise, contours created from surfaces con-taining breaks should always be generated based on the TIN or TGRD, not the Grid, to insure that the breaks are honored exactly.

When to use break lines

Break lines are needed only when the slope on either side of a the break line must be different. Break lines should be used only when necessary because they substantially increase processing time. The following sequence of figures represent the same input data and different resulting surfaces based upon whether polylines were extracted as point data (Extract to surface) or as break lines (Extract breaks).

Page 276 When to use break lines


Surface points plus three 3D polylines were extracted with Extract to surface. Note the curvature-induced sur-face overshoots. Deriv-atives are set to 2.

TGRD with no break lines The middle 3D polyline was extracted as a break line with Extract Breaks, but the outer two were not. Over-shoot still occurs ar the bottom of the low area and on the right side. Notice the densification of the 3D polyline selected as a break line.

TGRD with center 3D polyline only selected as break line

When to use break lines Page 277


Extracting all three 3D polylines as break lines creates the desired result.

All three break lines used

3D polylines may be used either as break lines (Extract Breaks) or simply as surface control (Extract to surface) depending on whether abrupt slope changes or smooth curvature is the desired result.

Page 278 When to use break lines

Chapter 11: Drape

Drape is a very powerful tool. Any object may be translated ver-tically until its Z values conform to the current surface. Drape creates a new draped 3D drawing entity and deletes the original source entity. The command syntax and settings are covered in the Command reference and the Configuring Quicksurf chapters.

Drape may be used to solve for the Z value of a surface at a group of points such as construction stake-out plans, fluid flow or finite difference model nodes. It is particularly useful for combining 2D maps and 3D models of the same area, by converting 2D map data into 3D data draped on topography. Any line or polyline draped onto the surface becomes a 3D profile. Exploded hatch patterns may be draped on a surface to create 3D thematic maps.

Concepts

Drape alters drawing entities so they conform in elevation to the current surface in surface memory. Draping a point entity is the simplest case. The Z value of the point entity is changed such that it lies in the surface. How this elevation value is solved for is determined by the Configure Drape settings.

Drape basis

Within the Configure Drape dialog you may specify to drape to the Planar TIN, TIN (using curvature), TGRD or Grid.

Draping requires a sur-face to contain a TIN, TGRD or Grid. You cannot drape to a sur-face containing just points.

The Planar TIN represents the surface as the TIN with no curva-ture within any one triangular face. The elevation of a point or node is calculated on the planar triangular face. If a linear entity (line or polyline) is draped using this method, vertices are only added where it crosses a triangle edge. This results in the least number of vertices in the draped line, yet it honors the surface exactly.

Concepts Page 279

Chapter 11: Drape

Draping to the TIN uses the derivatives along with the TIN to drape on the complete mathematical description of the surface, including breaks if present. This is more accurate than draping on the TGRD or Grid, which represent a sampling of the mathe-matical surface at an interval based on the cell size used. Because derivative (slope and curvature) information is used, the settings for Derivatives in the Configure Grid dialog are used. Specify-ing None is the same as Planar TIN above. Specifying 1st or 2nd uses continuous slope or continuous curvature respectively.

Draping to the TGRD or Grid interpolates between the triangle or grid cell vertices, rather than solving the underlying mathematical surface. Draping to the TGRD or Grid does make sense in cases where the grid or TGRD nodes have been modified with surface operations such as Max, Min, or Trend, which alter the node ele-vations without respect to the TIN and derivatives.

Drape step

When draping an object consisting of lines and arcs, each seg-ment is subdivided based upon drape step size into smaller seg-ments by adding vertices. Each of these densified vertices is then draped onto the surface and becomes a vertex of a new 3D polyline resulting from the Drape command. The Configure Drape dialog controls drape step size. Drape step is ignored when draping to the Planar TIN.

Draping off the edge of a surface

If an entity, such as a line or polyline, extends past the edge of the defined surface, those parts of the line which do not overlie the defined surface are set to a constant elevation referred to as drape base. The elevation used for drape base is set in the Undefined grid value edit box within the Configure Grid dialog. It is a good practice to only drape entities which entirely overlie the surface or to use a boundary to clip them during draping if needed.

Page 280 Concepts

Chapter 11: Drape

Drape and Boundaries

If a boundary is enabled using the Set Boundary command, Drape only creates objects within the defined boundary. For example, if a rectangular boundary is in effect and a line to be draped extends outside of the boundary, the resulting 3D draped polyline will only be created within the boundary. No entities will be created outside of the boundary. As a consequence of this, draping an entity which lies totally outside of a boundary will not produce any resulting entity. This will have the same effect as an erase, because Drape erases the source entity and in this case produces no new entity.

Using Drape

Solving for an elevation

If you have experimented with the Track Z command, you have seen that Track Z interactively returns the Z value of a surface at the cursor x,y position. Track Z is simply calling Drape continu-ously to report the surface elevation. Drape can solve for the z values of a surface at many points for specific x,y locations. This is accomplished by drawing the desired x,y locations into the drawing as points at any elevation, then draping then them onto the desired surface. The Z values of these draped points will now reflect the surface elevation. You may post these values with the Post entities command or export them to an ASCII file with the Export data -> Entity XYZ data (DWG2TXT) command.

Many simulation models require filling of initial condition values for large numbers of model cells. This can be accomplished quickly and efficiently by draping the x,y cell configuration points to the initial condition surface, then exporting the draped points back to the simulation model.

Using Drape Page 281

Chapter 11: Drape

Creating a 3D profile

Draping a line, arc, 2D or 3D polyline will result in a 3D polyline representing the 3D surface profile. The flatten command may then be used to generate a 2D profile from the 3D polyline if desired.

Constructing design elements (break lines)

When modifying a surface to reflect a design or interpretation which includes break lines, proper placement of the break lines in 3D space is essential. Drape may be used in conjunction with temporary construction surfaces to build 3D polylines for use as break lines. Temporary construction surfaces may be made with the Build surface command or by extracting a handful of points or break lines to create a surface (such as a constant slope) upon which to drape a polyline having the desired horizontal align-ment. Complex 3D polylines may be created quickly and accu-rately in this way.

Converting 2D maps to 3D maps

Map information consisting of 2D line and polyline data such as roads, property lines or utility locations may be draped onto topography to create 3D models of the site. Hatch patterns repre-senting the areal distribution of a mapped property may be exploded and draped onto topography to build a 3D thematic map.

Page 282 Using Drape

Chapter 11: Drape

Application examples

Drape and post points

Assuming you have a surface containing at least a TIN in the <.> surface, the Z values at arbitrary locations on the surface could solved for and posted as follows.

Workflow

• Draw points at the desired x,y locations.• Drape the points onto the desired surface.• Post the Z values using Post entities

Command sequence

Draw points at the desired x,y locations.

PointPoint: enter desired X,Y; repeat for all desired locations

Drape the points onto the desired surface.

Design Tools -> DrapeSurface<.>: press enter to accept the <.> surfaceReturn to select all or Select objects: select just the drawn points, using layer control if needed

Post the Z values using Post entities

Annotate -> Post entitiesReturn to select all or Select objects: select just the drawn points, or use the following shortcut:

(answer P at this prompt to get the previous selection set)Text position: selectText height: selectText angle <0>: selectAlign (Left/Center/Middle/Right) <best>: select

These points could also be exported to an ASCII file using theExport data -> Entity XYZ data command.

Application examples Page 283

Chapter 11: Drape

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Horizontal arc to vertical curve

Many civil engineering design problems require a plan view arc of constant radius to follow a non-horizontal surface. Drape can change the Z values without altering the plan view radius of the curve.

Workflow

• Draw the horizontal alignment arc or polyline entity• Create the vertical alignment surface to be draped upon• Drape the entity onto the surface.

Command sequence

Draw the horizontal alignment arc entity, in this case a ten uniradius arc covering 90 degrees in the northeast quadrant.

ArcCenter/<Start point>: 0,0Center/End/<second point>:0,10End Point: 10,0

Create the vertical alignment surface to be draped upon. Let’use Build surface to create a sloping planar surface.

Design Tools -> Build surface

In the Build surface dialog, select Plane - 3 Points, and specify a window from (-100,-100) to (100,100) for the extents of the temporary surface. Upon clicking OK to exit the box you will be asked for three points defining the plane. Answer (0,0,0) (0,10(10,0,0). A plane with these properties will be created in the <surface ready for draping upon.

Drape the arc entity onto the surface.

Design Tools -> DrapeSurface<.>: press enter to accept the <.> surfaceReturn to select all or Select objects: select the arc entity

Page 284 Application examples

Chapter 11: Drape

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The arc is transformed into a 3D polyline with a constant horizon-tal radius. Viewing from an oblique viewpoint or listing the entity will allow you to see the differing Z values for the resulting verti-ces.

Hatch pattern draped on a surface

Let’s assume we need a 3D model with a hatch pattern drapethe surface. Hatch patterns are blocks in AutoCAD, unless spcifically created as an exploded hatch pattern. If you drape a block (insert entity) it is translated in its entirety until its insertion point lies in the surface. To drape the elements of a block, it mbe exploded into its component parts prior to draping. In the flowing example, we will explode a hatch pattern then drape it.

Workflow

• Create a surface upon which to drape• Draw or create the closed polylines to hatch• Hatch within the polylines• Explode the hatch pattern block• Drape the exploded hatch pattern

Command sequence

First lets load a surface upon which to drape. We will use theinternal terrain generator built into Quicksurf.

Utilities -> Quicksurf utilities -> Generate Terrain

Number of points to be generated <1000>: press returnGenerating [Flat, Rugged, Rolling, Mountainous] TerrainFinished Generating Terrain

This has created a 1000 point surface in the <.> surface, but hnot yet created any additional parts such as a TIN needed fordraping. Let’s show the contours. This will build a TIN, derivatives and a grid automatically.

Application examples Page 285

Chapter 11: Drape

see

Contour Surface <.>: press returnNone/Show/Draw/Redraw <Show>: press return

Now that we see where the surface exists, draw the closed polylines within which to hatch. Be sure that the polyline you draw entirely overlies the surface and is closed.

Command: PlineFrom point: pickArc/Close/Halfwidth/Length/Undo/Width/<Endpoint of line>: draw plineArc/Close/Halfwidth/Length/Undo/Width/<Endpoint of line>: Close

Hatch within the polyline.

Command: HatchPattern(? or name/U,style) <default>: LineScale for pattern< default>: choose a scale, adjust if neededAngle for pattern<default>: 45Select objects: select closed polyline

Explode the hatch pattern block. This is not required if you used the exploded hatch option of the hatch command.

Command: ExplodeSelect objects: select hatch pattern block

Next we will drape the exploded hatch pattern, but first let’s change to an oblique view where we can see the changes.

Command: VPOINTRotate/<View point> <(0,0,1)>: 1,1,0.5 (zoom extents if needed)

Design Tools -> DrapeSurface<.>: press enter to accept the <.> surfaceReturn to select all or Select objects: select the exploded hatch entities and the closed polyline

All of these entities are now in 3D lying on the <.> surface. Zoom to extents if needed to see you model. Show the grid tothe draped hatch pattern relative to the surface.

Page 286 Application examples

Chapter 12: Surface editing

Typically you will use Quicksurf to generate a surface model from a data set either loaded from an ASCII file or extracted from AutoCAD drawing entities. After generating and displaying a TIN, TGRD, grid or contours, you will often want to change the shape of the surface to reflect a proposed engineering design or to add interpretation is areas of sparse control. You accomplish this by adding extra control points (edit points) or 3D polylines repre-senting breaks. Merge extract and Break extract can add your edit data incrementally to the <.> surface. In some cases you will use the AutoCAD drawing to merge a subset of the original data points with edit points and/or break lines.

Examining the raw data

The first step in working with any surface is to load the known points and/or break lines and examine the surface visually. The best way to look at your raw data is to display the TIN from an oblique viewpoint such as (1,1,1). This example assumes your surface is in the results <.> surface, as it would be after an extract.

VPOINTRotate/ <View Point> <0.0000, 0.0000, 1.0000>: 1,1,1Regenerating drawing

Zoom the viewport to register over the surface.

View Options -> Surface ZoomSurface name <.>: Press enter

Show the TIN to see the extents of the current surface.

TINSurface name <.>: Press enter None/Show/Draw/Redraw <Show>: S

Examining the raw data Page 287


The TIN has no interpolated points or slope effects; it is just your raw data. Examine it and investigate any spikes or irregularities. This is where you will catch mistakes involving bad points, such as those extracted unrelated entities from the drawing (text, title blocks, etc.). The TIN is your base data set and you should cor-rect any apparent errors before further modeling.

Although examining your data is best from an oblique view, you will normally add edit points from plan view.

View Options -> Surface plan viewSurface name <.>: Press enterRegenerating drawing

Display the contours to see the current surface model. Adjust the contour interval as necessary.

ContourSurface name <current>: Press enter None/Show/Draw/Redraw <Show>: S

The contours represent the surface model (TIN, TGRD, grid) selected in the Configure contour dialog. If you are contouring on the grid, the properties of the grid are controlled by the Configure grid dialog. The grid and TGRD models can depart significantly from the basic TIN model you first looked at, because slopes and curvature effects now shape the surface.

What is an edit point?

An edit point is an extra point used to guide the surface in areas of sparse control or areas of rapid slope change. Edit points may be extracted from drawing entities with any of the Extract com-mands. Typically edit points are point entities, but 2D or 3D polylines are sometimes used.

You know much more about the expected behavior of your sur-face than Quicksurf does. Edit points are how you communicate this to Quicksurf so the resulting surface reflects you design or interpretation.

Page 288 What is an edit point?


Adding edit points

It is a good idea to place edit points and the original points each on their own layer. This is for ease of subsequent selection for Merge extract as well as keeping ground truth and interpretation (or design) separate. If you are going to use all of the original raw data points, there is no need to draw them into the drawing. If you are going to use a subset of the raw data points (perhaps excluding points in excavation areas) you will want to draw them in on their own layer.

Before adding additional edit points to the drawing, you need to know the Z values of the surface in the vicinity you wish to edit. You can either use the show mode of Post from memory to post the values of the original data points or use Track Z to investigate the surface interactively. You can sample the elevation of any surface which has a TIN, grid or TGRD by using the Track Z command. Track Z returns the elevation of the surface part selected in the Configure Drape dialog box.

Utilities -> Elevation Utilities -> Track ZSurface name <current>: Press enter

As you move the cursor over the surface and the surface elevation at the cross-hairs is displayed on the top status bar. Press a return to exit the Track Z command. Once you have decided upon the Z elevation for point(s) to be added, use the Elev command to set the Z value of the added points.

Command: ELEVNew current elevation <231.0000>: Specify new elevationNew current thickness <0.0000>: Enter zero

Now draw the new point(s) using AutoCAD’s Point command.Don’t confuse Quick-surf ’s POINTS and AutoCAD’s POINT com-mand

Command: POINTPoint: pick location

Adding edit points Page 289


You may add edit points as needed to the various areas of the sur-face you wish to modify. Other entities may also be used as a source of edit points, such as 2D polylines (if you want to draw a contour to control the surface). Most AutoCAD entities may be extracted with Quicksurf and therefore may be used as edit enti-ties, although points and polylines make the most sense.

Review the Concepts chapter if you are fuzzy on the difference between surfaces and drawing entities.

If the surface you are modifying in already in the results <.> sur-face, the next step is to use Merge extract to make a surface which is the combination of the points in the <.> surface and the new edit points. If the surface you are going to modify is in a named surface, use surface operations to copy it to the <.> surface. The reason is that Merge extract incrementally adds points to the <.> surface only.

Extract from drawing -> Merge extract

Return to select all visible orSelect objects: select your edit points

You may want to use the filters available via the Configure extract dialog box to aid in your Merge extract selection. The results <.> surface now contains the combination of the original points plus your edit points. Now contour the current surface again.

ContourSurface name <.>: Press enter None/Show/Draw/Redraw <Show>: S

...and you get a set of contours reflecting your changes. This technique has the advantage of repeatability. You will typically iterate through this several times refining your surface until it meets your needs.

By keeping your original data and edit points on separate layers, you may use your original data for posting using Post entities, yet contour the surface containing your edit modifications.

Page 290 Adding edit points


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Editing surfaces with break line data is similar in the sense that you use Extract breaks to incrementally add new break lines to the surface. Keep in mind, that if you alter a 3D polyline already extracted as a break line, then re-extract it, you are creating a stacked break line. The resulting break line in surface memory will be an average of the two, not the last one extracted. In these rare cases, recreate the surface from scratch.

Editing contour polylines

Manually editing the 2D polyline entities representing contours has no effect on surfaces in surface memory. Changes made to contour polylines are reflected in surface memory only if the altered contours are extracted with Extract to surface and a new surface created.

Editing contours doesn’t change surface memory!

Drawn contour polylines may be edited with AutoCAD’s pedit or stretch commands. Invoke the pedit command, select a contourthen select the Edit Vertex option.

Command: PEDITSelect polyline: select contour polylineClose/Join/Width/Edit vertex/Fit/Spline/Decurve/Undo/eXit _<X>: ENext/Prev/Break/Insert/Move/Regen/Str/Tan/Width/eXit/ _<N>: select

AutoCAD displays an X at the first vertex of the contour polyline. Press N (Next) or P (Previous) as necessary to move theX to a vertex you want to move; then press M to select Move. Pick a new location with the mouse; the vertex will move to thlocation and the contour will be redrawn. Repeat as many timas necessary to reshape the contour polyline as desired. The Straighten option of PEDIT allows you to discard vertices that aretoo close together. When you are done press X one or more tito exit PEDIT.

Editing contour polylines Page 291


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Quicksurf may occasionally generate a contour with a kink in it caused by three vertices very close to one another. Eliminating one of the three vertices with the straighten option of pedit will eliminate the problem.

Using the Stretch command together with grips is a convenient way to alter contours, but care must be taken not to corrupt the elevation of the contour. Using stretch with grips will move a vertex in XY as you move the cursor. The Z elevation of the ver-tex will be changed to the current elevation if the entity allows. For 3D polylines, this is a major problem, unless you constantly adjust AutoCAD’s elevation setting.

Manually editing contour polylines can corrupt the elevation information carried within the polyline. AutoCAD carries elevation data in two separate places for a given 2D polyline and mually editing polylines can cause these two elevations to be inconsistent. Occasionally these corrupted polylines will causthe Label Contours command to label the wrong elevation (typi-cally zero). This only occurs on edited polylines.

These technique are simply hand modifications to the contourdrawings. Modified contours may be extracted as a source of points, but generally just adding points is more efficient. If youare going to build profiles, drape objects or calculate slopes ovolumes, you need to change the surface, not just the contours.

Correcting slope excursions

When modeling using the Standard method (continuous curva-ture) with Derivatives set to 2nd within the Configure Grid dialog, Quicksurf enforces continuous curvature of the resulting sur-face. This means that the local slopes at each data point are jected into the areas between points in such a way that continusurface curvature is maintained. For most data sets, this prodwell behaved smooth surfaces.

Page 292 Correcting slope excursions


Slope-induced problems can occur when two points are close to one another and have different elevations. If this occurs in an area with little or no nearby control to constrain the surface, Quicksurf extrapolates the surface into these areas honoring the steep slope generated by the pair of points. This produces a artifi-cial high on one side of the points and an artificial low on the opposite side of the points.

The root of the problem is the steep slope generated by two nearby points, not their absolute z values. Two points a distance

apart of horizontally and vertically still produce a 45 degree slope, even though the points are visually indistinguish-able. This slope is honored by Quicksurf.

There are two choices in this situation. Either eliminate one of the points (if they are redundant), or add edit points to constrain the surface (if the points are valid).

Slope induced overshoot problems from one bad point

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109–

Correcting slope excursions Page 293


Removing the bad point produces a normal map

The characteristic high-low pair of overshoots is a symptom of two close points producing a steep slope. When you encounter such cases, show the TIN to quickly determine the offending point. The TIN line adjacent to the problem connects to the bad point. Either correct the elevation, delete the point, or add edit points or polylines to constrain the surface.

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Chapter 13: Site planning workflow

Efficient use of Quicksurf for most site planning problems entails creating a model representing the existing site, analyzing the existing topography, then building your design by modifying the existing model. By starting with the existing surface, you develop a base model upon which to build. Slope analysis, drain-age design and cut/fill volumes will all be dependent upon a valid base model. This short chapter simply gives an overview of the workflow and some of the possible commands used at each step in a typical design process.

Workflow Overview

• Create and save a surface of the existing site topography or more of these commands:

Read ASCII points or Read ASCII table ASCII fileRead QSB Binary QSB fileExtract to Surface or Merge Extract Drawing entitiesTINSurface operations Copy

• Correct any errors in the original surface data.

• Analyze the surface, if necessary

Use Color options -> Surface colors to color the surface by elevation, slope, visibility, light or shadow as required, then TIN or Grid and show the surface. Perspetive views using Surface view can help in site visualiza-tion. The slopes may be contoured by using Surface operations -> Degree slope to make a surface represent-ing slope, then use Contour to display it.

• Analyze existing drainage flowlines using 3D flowlines, if needed.

Workflow Overview Page 295

Chapter 13: Site planning workflow

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This design sequence creates 3D polylines for use as break lines.

• Create your design elements, first drawing control lines, thusing Intersect slope and Apply section as needed to deter-mine slope intersections. During this stage you will com-monly use some of the following commands, mostly from thDesign Tools menu:

Build surface (for temporary surfaces to Drape upon)Drape (to place objects in correct 3D position)Flatten (to build 2D profiles from 3D polylines)Cross-section (to build 2D profiles from 2D polylines)Vertical align (to adjust vertical profiles)Intersect slope (to determine slope-surface intersections)Apply section (to apply a 2D section to a 3D control line)

• Create your proposed design surface using some of the folowing commands:

Extract to surface or Merge extractExtract BreaksTINTGRD

The design area and the existing undisturbed area areseparated by the daylight line, being the 3D polyline which ties the existing surface to the design surface. Your proposed design surface will consist of the existinsurface control points in undisturbed areas and your ndesign break lines and points in the altered area. Youwill be using layer management and perhaps Set Bound-ary to insure that you keep the original existing surfacecontrol points and your newly drawn design points andbreak lines separate.

• Determine cut and fill volumes using Area volume.

• Analyze final design surface drainage flowlines using 3D flowlines, if needed.

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Chapter 14: Volumetrics

Fast, accurate volumes are very important in most surface model-ing applications. Within Quicksurf, volumes may be computed directly from surfaces residing in surface memory using the Sur-face volume, Area volume or Boundary volume command or computed from a drawn TIN, TGRD or Grid using the Volume by entity command. None of these volume functions use the current boundary which may have been set with the Set Boundary com-mand, rather they may prompt for one or more closed polylines representing areas under which to calculate volumes.

TIN based volumetrics

Quicksurf calculates volumes of a surface by summing the vol-ume underneath each face of the surface within the area specified. A face may represent the either the triangles of a TIN or Triangu-lated Grid; or the rectangular grid cells of a Grid.

Volume under a triangle

For any surface with a TIN, calculating a volume consists of cal-culating the volume under each triangle in the desired area and summing the result. Remember that regular TINs and Triangu-lated Grids are both types of TINs. First let’s look at one triangof a TIN and determine its volume.

TIN based volumetrics Page 297


Volume under one triangle

The volume under a triangle is measured relative to the zero (XY) plane. The Z value of the surface used in a volume command represents thickness. If you use the Surface volume, Area volume or Boundary volume commands, you may also calculate the vol-ume between two surfaces or the volume between a surface and a constant. In these two cases, Quicksurf calculates the thickness surface and places it in the results <.> surface. A Z value of zero in this surface represents zero thickness. All volume calculation is then performed on this thickness surface.

If you have subtracted an existing topographic surface from a proposed topographic surface, areas of fill will have positive thickness values and areas of cut will have negative thickness val-ues. When volumes are then calculated, positive (fill) values are calculated as positive volumes and negative (cut) values are cal-culated as negative volumes. Reversing the order of the surfaces in the calculation will reverse the sign (+/-) of the resulting vol-umes.

Page 298 TIN based volumetrics


Volume under a surface

Calculating the volume under a surface consisting of triangles is accomplished by summing the individual volumes of the compo-nent triangles within the area to be calculated.

Volume under part of a TIN

Entire surface

If we want the volume under an entire TIN, we may simply draw the TIN and use the Volume by entity command and select the drawn TIN. If the TIN was drawn as a polyface mesh, select the one polyface entity. If the TIN was drawn as individual 3D faces, select all of the 3D faces. It is easier to use the Surface volume command which returns the same result, but does not draw any AutoCAD drawing entities.

Partial surface volume

To determine the volume under a sub-area of a surface, we first must be sure that the edge of the TIN we are drawing follows the outline of the sub-area boundary. There are several ways to accomplish this. For understanding how partial volumes are cal-

TIN based volumetrics Page 299


culated, we will manually step through the procedure used inter-nally by Area volume and then use the Volume by entity command to calculate the volumes. Once you are comfortable with the method, you will use the Area Volume command for this purpose, which is fast, automatic and does not draw drawing enti-ties.

Understanding volume calculation

The following example proceeds step by step in calculating a TIN volume beneath an irregular boundary. The Area volume com-mand will do this in one command, but we will step through the procedure manually and use the Volume by entity command for a more complete understanding. Assume we have two surfaces named Existing and Proposed and we need to determine the vol-ume between the two within an arbitrary boundary polygon which entirely overlies the TIN when viewed from plan view. The boundary within which we want to calculate volumes is typi-cally defined by a closed 2D or 3D polyline.

Volume within an irregular boundary

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Workflow

Normally you will use the Area volume com-mand which does this in one step.

• Create and TIN the Existing surface• Create and TIN the Proposed surface• Calculate thickness (Proposed - Existing) with surf operations• Drape the boundary polyline onto the thickness surface• Extract this draped polyline as both a break and a boundary• TIN the thickness surface and draw the TIN• Run the Volume by entity command on the drawn TIN

The actual command sequence to accomplish this follows. It assumes that a boundary polyline and the data points are drainto the drawing and that appropriate layers are toggled prior extracting points.

Extract to surface (QSX) Extract Existing points

TINSurface <.> : <.>

Rename <.> surface to Existing with Surface operations dialog

Extract to surface (QSX) Extract Proposed points

TIN <.>Surface <.> : <.>

Rename <.> surface to Proposed with Surface operations dialog

Calculate (Proposed - Existing) with surface operations

TIN Creates the thickness surfaceSurface <.> : <.>

Design tools -> DrapeSurface <.> : <.>Return to select all orSelect objects: Select boundary polyline

Understanding volume calculation Page 301


Extract Breaks (QSBX)Return to select all orSelect objects: Select draped boundary polyline

TIN Draw the TINSurface <.> : <.>None/Show/Draw/Redraw: DrawLines/3DFaces/Polyface: PolyfaceSelect invisibility...All/Interior/None <None>: None

This TIN represents the thickness surface. Areas above the zero (XY) plane represent fill and areas below the zero plane represent cut. This is because we calculated Proposed - Existing. If you reverse the order of the calculation, you will reverse the relation-ship of positive and negative areas versus cut and fill areas.

Creating a thickness TIN for volume calculation

Always examine the thickness surface by examining the TIN from an oblique view, or displaying contours, prior to calcu-lating volumes. Is the surface reasonable? Many common

Page 302 Understanding volume calculation


errors, such as incorrect boundaries or bad data points, will be very apparent. If the thickness surface passes inspection, calcu-late its volume.

Volumetrics -> Volume by entityReturn to select all orSelect objects: Select drawn TIN

The volume under each face is calculated and summed together to result in the total volume within the irregular boundary.

The resulting volumes are reported in three parts:

Positive volume The volume above the zero plane (fill)Negative volume The volume below the zero plane (cut)Net volume The sum of these two volumes (balance)

If the net volume is zero, then the cut volume equals the fill vol-ume.

This was a fairly long sequence of commands, but you can observe the calculation step-by-step. In practice, you would use the Area volume command, select the two surface names and the boundary polyline and the volumes would be automatically cal-culated and reported.

Volume by Entity

Volume by entity calculates the volume under AutoCAD drawing entities. Unlike Surface volume, Area volume and Boundary vol-ume which operate on surfaces in memory, Volume by entity only operates on drawing entities such as meshes, polyface meshes and 3D faces drawn with the TIN, TGRD or Grid commands.

Volume by entity


Volume by Entity Page 303


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Select objects via the normal AutoCAD object selection methods. Quicksurf will calculate the volume under the selected entities in cubic drawing units. 3DFACEs, Polyfaces, and 3D polygon meshes are the only entity types that will yield a volume; all other entities are ignored. The status bar will be updated with the total as it is calculated. Volume by entity computes three results: a pos-itive volume for objects above the zero datum (x,y) plane, a nega-tive volume for objects below the zero datum plane, and a net volume.

Volume by entity always calculates volumes relative to the zero plane (XY plane) of world coordinate system. If you want the volume calculated with reference to a different plane from the zero datum, use the AutoCAD Move command to move the drawn TIN or GRID vertically to the desired level.

Either grid cells or triangles may be used to compute a volume under a surface, but they generally yield slightly different results: triangles are treated as flat faces, whereas the grid represents uni-form sampling of a smoothed curved surface that passes through all the control points. If the grid is a 3D polygon mesh, a single value of volume for the entire mesh is calculated. If the grid con-sists of individual 3DFACEs or Polyfaces they are calculated for all selected faces, then summed and reported.

If the resultant faces extend both above and below zero datum, those faces above the zero plane are reported as positive volumes and those faces below the zero plane are reported as negative vol-umes. If a single face penetrates through the zero plane, a single net volume is calculated for that face, rather than separate posi-tive and negative portions.

All of Quicksurf’s volume commands will produce identical results when run on the same surface parts. Volumes run on TIN, TGRD and Grid of the same surface will yield different results, because of different amounts of curvature information

Page 304 Volume by Entity


carried by the different surface parts. TGRDs and Grids may reflect surface curvature, regular TINs do not. Always visually examine a surface prior to calculating its volume.

Volume calculation from surface memory

Volumes may be computed directly from surfaces residing in sur-face memory using the Surface volume, Area volume or Bound-ary volume command. None of these volume functions use the current boundary which may have been set with the Set Boundary command, rather they prompt for closed polylines representing areas under which to calculate volumes if areas are required. These three commands all invoke the same dialog box.

Surface Volume dialog box

Volume calculation options

Volume may be calculated between a surface and the zero plane (i.e. sea-level), between a surface and a constant elevation, or between two surfaces. If the volume requested is between two surfaces or between a surface and a constant, the results surface <.> will contain the actual thickness surface for which the volume is calculated. You may show or draw this surface to confirm its geometry. Always inspect the thickness surface prior to volume

Volume calculation from surface memory Page 305


calculation by showing the TIN, TGRD or Grid from an oblique viewpoint or by contouring it. In some cases the edges may con-tain anomalies; either correct the surface or exclude the edge effect by using Area Volumes.

Within the dialog box you may specify the basis for the volume (Planar TIN, TIN with derivatives, Grid or TGRD), the first sur-face, optionally a second surface or constant, and output file name and type.

Basis for volume calculation

Planar TIN Calculate volumes based on the planar TIN.TIN w/ Deriv Calculate volumes using the TIN and derivatives.Grid Calculate volumes based on the Grid.TGRD Calculate volumes based on the TGRD.

The volume will be computed on the selected surface part. If the part does not exist, the selection will be grayed-out. The Planar TIN selection will always be available and a TIN will be created if required.

First surface name

Select the surface under which to calculate volumes from the sur-face pick list. If this surface represents thickness, the volume should be computed between this surface and the zero (XY) plane. In this case you would specify None for the second sur-face. If the volume to be computed lies between two surfaces or between one surface and a constant elevation you will need to specify the second surface or constant.

Second surface name

If the desired volume is between two surfaces, click on the check box next to the surface pick list and select the second surface from the pick list. A new surface representing the difference between the two surfaces (first surface minus second surface) is computed and placed in the results <.> surface and the volume is calculated.

Page 306 Volume calculation from surface memory


Internally this computation uses the TIN, derivatives, grid and/or TGRD with the Maximize option within the surface operation subtract. This insures the most rigorous resulting thickness sur-face. If you want curvature used when calculating the volume between two surfaces, use the TIN with derivatives option.

Two surface example

If you have two surfaces EXISTING and PROPOSED and select PROPOSED as the first surface and EXISTING as the second sur-face, the results <.> surface will contain your cut/fill surface. Positive areas (P - E > 0) represent areas of fill and positive vol-umes represent the fill volumes. Negative areas (P - E < 0) repre-sent areas of cut and "negative" volumes represent the cut volumes. Positive and negative volumes represent the volumes above and below (respectively) the zero (XY) plane of the surface being computed. The net volume reported is the sum of positive and negative volumes. When the net volume equals zero, the cut and fill volumes are the same.

Constant

If the desired volume is between a surface and a plane of constant elevation, select the check box next to the Constant selection and enter the constant value in the edit box. A surface representing the difference between the first surface and the constant (first sur-face minus constant) is computed and placed in the results <.> surface and the volume is calculated.

This option is convenient for determining reservoir volumes at different water levels.

None

The volume between the first surface and the zero plane is com-puted. Select the check box next to None. Use this for comput-ing the volume of a surface already representing thickness.



File output

The resulting volumes are always displayed on the text screen, but may be optionally written to a text file. Select the check box of the desired option and press the File button and supply a file name up to eight characters in file dialog. The appropriate file type (.txt) will be appended.

ASCII Writes an ASCII text file.None Does not write a file.

If a volume units conversion factor and units name has been spec-ified in the Configure Units dialog, the volumes will be converted and displayed in the specified units.

Label areas

Area volume and Boundary volume allow for the volumes under multiple sub-areas of the surface to be calculated. When multiple area polygons are selected, selecting the Label Areas checkbox will cause each polygon to be sequentially labeled with area num-bers. These area numbers correspond to the area numbering in the volume report. The labels are placed on the current layer, in the current text style, and at a text height equal to the grid cell size, unless overridden by a current text style containing a fixed text height. The areas are numbered in the order the are selected.



Running a volume command

After selecting the options in the Surface Volume dialog box and pressing OK, you are prompted to select area polygons (if needed) and the calculated volumes are displayed on the text screen. The volume results are written to the file or database table if requested.

Volumes reported

The volume report produced looks similar to the following:

VOLUMES: Reported in Cu.Yds.Using 0.37037 cubic units/Cu.Yds.

Area Positive Volume Negative Volume Net Volume1 15025.1 14215.5 809.62 10215.3 9812.4 402.93 982.5 3402.5 -2420.0

Total 26222.9 27430.4 -1207.5

For each area three numbers are reported:

Positive Volume: The positive volume within the area polygon.Negative Volume: The negative volume within the area polygon.Net Volume: The net sum of volumes within the area polygon.

A Total Positive Volume is reported representing the total posi-tive volume of the entire surface. A Total Negative Volume is reported representing the total negative volume for the entire sur-face. Positive volumes represent areas with Z values greater than zero and negative volumes represent areas with Z values less than zero.



If you have selected a volume conversion factor and unit name in the Configure Units dialog box, the volumes reported will have the conversion factor applied and the units name will be dis-played. There is no validity checking on user-supplied units con-version factors.

The three variations of the volume command are individually described below.

Surface volume

The Surface volume command calculates the volume under an entire surface in surface memory. If you are using this volume to compare to a volume computed under a different surface, you must insure that the area covered by the two surfaces are identi-cal.

Area Volume

The Area volume command calculates the volume under one or more sub-areas of surface in surface memory. Each sub-area is defined by selecting a closed polyline representing the area under which the volume is to be calculated. You may select as many sub-areas as you wish.

Caution: Area polygons should not overlap!

Be careful not to overlap or nest area polygons, or incorrect results will be obtained. If your area polygons are adjacent to one another use OSNAP when constructing the polylines to insure that adjacent area polygons share vertices.

The surface part used for volume calculation (TIN, Grid or TGRD) must be defined in the area covered by the area polygon. If a surface is not defined under part of an area polygon, the unde-fined area contributes no volume to the reported volumes.

Volumes may be calculated between a surface and the zero plane (i.e. sea-level), between a surface and a constant elevation, or between two surfaces. If the volume requested is between two



surfaces or between a surface and a constant, the results surface <.> will contain the actual surface for which the volume is calcu-lated. You may show or draw this surface to confirm its geome-try.

Internally, Area Volume performs the same sequence as described in the volume example earlier in this chapter. Each area polygon is conceptually draped on the surface, densified and used as a break as well as a boundary, then the volume is computed within the area polygons boundary. This is done for all area polygons selected and the report is written to a file or database file.

Boundary Volume

Boundary volume is a special case of Area Volume where the thickness surface being calculated tapers to zero and the specific "zero-line" polyline must be honored, even if it crosses TIN or Grid boundaries. This command should not be used for general volume calculation: use Area volume instead.

Boundary volumes was designed for petroleum industry calcula-tion of "hydrocarbon pore volume" maps. In these situations a negotiated zero-line representing the absolute tapered zero edge of the hydrocarbon accumulation is determined and must be hon-ored exactly by all volume calculation. The zero-line polygon should be drawn at an elevation of zero. The Z value of the sur-face being calculated is forced to zero everywhere along this zero line. This is quite different from the polygon area boundaries which honor the Z value of the surface.

This command is for special cases such as stockpile volumes where the toe of the pile is known exactly, or other volume prob-lems where the surface being calculated tapers to a known zero edge. For general volume problems, use the Area Volume com-mand instead.



Practical volume calculations

When calculating a volume, you must choose whether to base the volume on the TIN, the Triangulated Grid or a regular Grid. The choice depends upon whether break lines are present in your sur-face and whether surface curvature between data points is desired. The differences are listed below.

Planar TIN Planar faces, honors breaks, no curvatureTIN w/ deriv. TIN (using curvature for drape), honors breaksGrid No break lines, uses curvature if presentTGRD Break lines and curvature

Planar TIN volumes

Calculating the volume from a TIN uses the planar faces of the triangles for volume calculation. Break lines are honored exactly by the TIN. TINs are used for data sets in which there is suffi-cient control that inter-point curvature may be ignored or is not desired. Examples include volumes on sites with dense control (such as dense contours or points from a stereo-plotter) or sites with mainly break lines such as benched pits.

Choosing TIN based volumes means that linear interpolation between the points and densified break lines accurately describes the surface.

TIN volumes using derivatives

Calculating the volume from a TIN with derivatives uses the pla-nar faces of the triangles of the <.> surface for the actual volume calculation, but uses curvature (derivatives) internally when drap-ing one surface to the other to determine thickness. Break lines are honored exactly by the TIN. TIN with derivatives is used for volumes between two surfaces in which inter-point curvature is significant. Examples include volumes on sites with sparse con-trol on one surface where Quicksurf-supplied curvature is needed to properly represent the surface.

Page 312 Practical volume calculations


Grid volumes

If your surface contains break lines use the TIN or TGRD for volumes.

Calculating the volume from a Grid uses the average elevation for each grid cell multiplied by its plan-view area for volume calcula-tion. Grids are used for data sets which have no break lines and inter-point surface curvature is desired. Examples include vol-umes on sites with sparse control (such as spot elevations on roll-ing topography) or sites with smooth rolling surfaces and no break lines.

Choosing Grid based volumes means that a grid accurately describes the surface, even though the grid will not have grid nodes exactly at control points. If you choose Grid based vol-umes on a surface containing break lines, an error message will result. Surfaces containing break lines should have volumes based on either the TIN or TGRD, because a grid tends to average across break lines.

TGRD volumes

Calculating volumes using TIN with deriva-tives is usually more efficient.

Calculating the volume from a TGRD (Triangulated Grid) uses the planar faces of the triangles of the TGRD for volume calcula-tion. Break lines are honored exactly by the TGRD. TGRDs are used for data sets in which both inter-point curvature and break lines are needed. Examples include volumes on sites with rolling topography mixed with abrupt cuts, ditches or walls. A golf course green together with its associated sand traps would be such a case: Curvature is needed on the green and in the bottom of the sand traps, but the edge between the sand traps and the green will be break lines. The TGRD is a special type of TIN which has densified vertices along break lines and vertices at grid nodes away from the break lines which honor surface curvature. The resulting surface honors both curvature and break lines.

Choosing TGRD based volumes means that both breaks and sur-face curvature are needed to accurately describe the surface.

Practical volume calculations Page 313


Boundary conditions

The surface must be defined everywhere underlying the area polygon for which volumes are to be calculated. If the area poly-gon extends past the defined surface, only the part of the surface within the polygon will be calculated. Any portion of the area polygon without the surface underlying it is assigned a volume of zero.

It is a good practice to display the TIN, Grid or TGRD (using the Show option) in plan view and compare them to your area poly-gons prior to calculating a volume. This allows you to confirm that the surface is defined everywhere beneath your area poly-gons. If your area polygon extends past the edge of your surface, you have two choices: Alter the area polygon or extend the sur-face by adding additional control points.

Remember that Area volume and Boundary volume do not allow nested or overlapping polygons. Nested polygon cases may be accomplished using boundaries, draped polylines as breaks and the Volume by entity command.

If you are using Volume by entity, you must drape the area poly-gon onto the surface, then extract it as both a break and a bound-ary, prior to drawing the TIN. In this case it is extremely important that the draped polyline (now a 3D polyline) reflects the correct Z value as it traces the area boundary. Always inspect the TIN visually prior to calculating volumes.

Comparison to Average End Area volumes

Many users may be more familiar with Average End Area vol-ume calculation, rather than TIN based calculation. Average End Area calculations involve generating a series of sections across the model, then multiplying the average area of adjacent sections by the distance between them. The implicit assumption is that the change in the surface between adjacent sections is linear and no surface curvature occurs between sections. To approximate this, many sections must be created. Yet in the end, the problem with

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Average End Area is the first word in its name: Average. The accuracy of the result is variable, depending upon section spac-ing. The TIN honors every data point exactly and the volume beneath each triangle of the TIN is a discrete fixed volume, not an average. A TIN based model is faster, more accurate, and sim-pler to use.

Common volume calculation mistakes

The most common user mistakes in calculating volumes relate to boundary conditions. The following guidelines should be reviewed:

• The thickness surface must be defined under the area to bcalculated.

• If the difference between two surfaces is used, both originsurfaces must be defined under the area to be calculated.

• Area polygons should not overlap or be nested.

• Inspect the surface visually by contouring it in plan view or viewing the TIN, Grid or TGRD from a perspective view prior to calculating the volume. Is it reasonable?

• Calculate the volume of the appropriate surface part basedthe guidelines in Practical volume calculations earlier in this chapter.

• If you are comparing resulting volumes calculated from different surfaces, they must be computed under exactly the same area to have any meaning.

• If you are using a volume conversion factor in the Configure Units dialog box, a mistake in entering the conversion factowill be reflected in all volumes reported.

Practical volume calculations Page 315

Quicksurf

Chapter 15: Surface estimation methods

Quicksurf supports many surface estimation methods. No one method works perfectly for all data sets. This short chapter is designed as a guide for selecting the method and settings which are appropriate for different data sets.

Supported methods

Surface models may be built based on a TIN or a grid model. Grid models may be created using many variations of curvature based or variogram based algorithms.

Triangulated Irregular Network (TIN)

The TIN is the basis for all Quicksurf methods. The TIN by itself represents the optimal triangulation of the input data set. Quick-surf honors the Delauney criterion for triangulation by adjusting each triangle within the network to be as close to equilateral as possible.

A TIN is the set of interconnected planar triangular faces con-necting the input control points. The surface of the TIN repre-sents the elevation computed by direct linear interpolation between the control points. Contouring on the TIN or draping on the Planar TIN solves for elevations based upon this linear inter-polation surface.

The Quicksurf triangulation algorithm is extraordinarily fast. Using the TIN for quick surface examination or draping upon is very efficient. Due to the speed of triangulation, Quicksurf is able to repeatedly triangulate to rapidly converge on complex break line auto-densification problems.

Supported methods Page 317

Chpater 15: Surface estimation methods

Slope-based methods

The Standard method of Quicksurf uses the TIN as a framework and computes first derivatives (slope) and second derivatives (curvature) at each vertex of the TIN. The slope calculation uses neighboring points and a slope weighting factor based on dis-tance. This results in slope and curvature values for the three ver-tices of each triangle. A mathematical surface is then calculated describing the elevation (z value) anywhere within the triangle. This surface may have different shapes based upon the Deriva-tives settings in the Configure Grid dialog. The choices include using continuous slope and curvature (default), continuous slope only, or using the planar faces of the TIN. Grids or TGRDs are then computed by solving the mathematical surface at each grid node.

Derivatives

The Derivatives setting is used by many com-mands.

The derivatives setting controls the intra-triangle curvature used when computing a z value. Grid, Drape, Cross-section and numerical Surface operations all rely on these settings when determining a surface elevation. These settings are in the Config-ure Grid dialog.

None

Setting Derivatives to None results in the planar face of the TIN being used for z value calculation.

First

Derivatives to 1st results in first derivatives only (continuous slope) being used for z value calculation within a triangle.

Second

Derivatives to 2nd results in first and second derivatives (contin-uous slope and curvature) being used for z value calculation.

Page 318 Supported methods


f

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Blend order

Using the slope and curvature constraints in the derivatives set-ting, Quicksurf generates a polynomial surface for each triangle. Blend order controls how the transition between adjacent triangle polynomials is handled. Generally blend order should be set to the same value as used for derivatives. Blend order has no effect with derivatives set to None, because no blending between curved polynomial surfaces is done.

Constraining slopes

Selecting 1st or 2nd derivatives causes slopes to be projected between control points. Generally this is desirable, but in certain irregularly spaces data sets this can cause projected surface highs or lows in areas with no points, but steep slopes on the perimeter. In these areas the resulting surface may be higher or lower than the input data set. These overshoots may be constrained with the Honor local extrema option. This forces the slope to zero (flat) at local highs or lows in the input point data, thereby eliminating overshoot.

Geostatistical methods

Many variations of kriging are included in Quicksurf. Kriging uses the statistical relationship between the variance of the sur-face versus inter-point distance to develop a surface model. Krig-ing does not use slope and curvature, therefore it works well with data sets which exhibit curvature-based overshoots with Quick-surf’s standard method. Kriging theory is beyond the scope othis manual, but a brief overview is included the Variogram Design section of the Command reference chapter.

Kriging builds a grid directly from the input points and the Nug-get, Range, Sill and Variogram type specified during variogram design. A TIN is constructed during kriging to be used for neigborhood determination. Kriging does not support break line dcontinuities.

Supported methods Page 319


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Kriging is excellent for concentration data sets or very small data sets in which there are not enough points for curvature based methods to be meaningful. Small data sets do not provide enough points for reliable variogram design, but if the variogram parame-ters are known they may be specified discretely in the Configure Grid dialog, and a meaningful map produced.

Which method do I use?

Quicksurf’s default method is to contour on a Grid created with the Standard method and Derivatives set to 2nd. This produces a surface with continuous slope and curvature. For most topographic data sets with uniform sampling this produces excelleresults. If the data sampling is very non-uniform (such as linebase geophysical surveys) or the slope changes are extreme (as concentration/contaminant data) different settings or methomay needed to produce the desired map.

Workflow

The following steps outline how to examine an unknown data and choose a contour and grid method.

• Load the points into surface memory

• Use Surface Zoom to align the view and the surface

• Show the TIN

• Examine the data in plan view. Correct obvious data erro

• Use VPOINT and Surface Zoom to establish an oblique view

• Show the TIN

• Examine the data. Correct any obvious elevation errors

• Once any bad points have been fixed, revert to plan view

• Set to contour on the TIN in the Configure Contour dialog

• Set the contour interval to Auto using 20 intervals

Page 320 Which method do I use?


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• Show the contours (Contour color by cycle helps visibilityThis is the linear interpolation of your data set. Any prob-lems you see here relate to the raw data, not the method.

• Select to contour on the Grid in the Configure Contour dialog.

• Set Standard method, 2nd derivatives, Honor local extrema in the Configure Grid dialog.

• Show the contours (now based on continuous curvature)

• If you have angular contours due to too large a grid cell sizuse Surface Options -> Cell size to adjust the cell size.

• If you have overshoot problems, change derivatives to None in the Configure Grid dialog.

• Delete the existing Derivative and Grid surface parts usingthe Surface operations dialog and the Clear parts button.

• Show the contours (builds a new grid with your changes)

• If this is still unacceptable try kriging. See Variogram Design in the Command reference chapter.

Data types and surface methods

The following outline of data types and suggested methods should be viewed with great skepticism. Each data set is uniqand has different requirements. These are just starting points

Topography Standard method; 2nd derivativesGeophysical line-based Standard method; None derivativesConcentration Krige method; Spherical variogramAngular site plan Contour on TIN; no grid usedSurfaces with breaks Standard method; 2nd derivativesIsopach maps Standard method; 2nd derivativesStructure maps Standard method; 2nd derivativesFaulted structure maps Standard method; 2nd derivatives

Contouring on the TIN always shows the raw input data.

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Chapter 16: 3D Studio meshes

The combination of Quicksurf with Autodesk’s 3D Studio animtion and rendering package provides for photorealistic renderestill images or stunning fly-through/drive-through animations oyour model. Surfaces may be segregated into related patcheease of materials application. Quicksurf can create morphablmeshes, allowing you to display a surface changing shape ovtime. Contaminant flow animations may be constructed whichshow the movement of an iso-concentration surface over time

Exporting mesh objects

The basic 3D Studio geometry entity is a mesh object. Quicksurf can write any surface as a 3DS mesh object directly from surfmemory to a .3DS file, ready to be merged into any other 3D Sdio file. Drawn polyface mesh entities within AutoCAD may bexported to 3D Studio using DXFOUT, then imported into 3D Stu-dio. Each method has pros and cons. All Quicksurf-generatemesh objects or polyface mesh entities are rigorously createdwith their face normals pointing up, thereby allowing you to usone-sided materials within 3D Studio.

Direct surface export

Entire surfaces may be written directly from Quicksurf surfacememory to .3DS mesh files using

Export data -> Surface data -> Write 3DS file

This is very efficient because no AutoCAD drawing entities orlarge DXF disk files are required. The mesh object which is wten represents the entire surface and is identical to the object ated by drawing the entire TIN, TGRD or Grid and transferringto 3D Studio using DXF.

Exporting mesh objects Page 323

Chapter 16: Creating 3D Studio meshes

There is a 65,456 face limit on 3DS mesh objects. If you attempt to export a surface with more than this number of faces, an error message will result. In such cases, the Surface Region command can be used to automatically partition large surfaces into polyface mesh entities of acceptable size for DXF export. The command is found under Design Tools -> Surface Region.

Subdividing surfaces

Quicksurf surfaces may be subdivided into smaller related patches with the Surface Region command for ease of materials application within 3D Studio. Surface Region is used for two main functions: 1) Creating one 3DS mesh object representing different surface patches which will have the same material applied; and 2) Automatically partitioning a large surface into smaller polyface meshes which fall within the face count limita-tions imposed by AutoCAD and 3D Studio.

Related surface patches

A Quicksurf surface may cover an area which has many different types surface materials. Consider a golf course example. Although a given hole is represented by a single surface model, different parts of the surface will be covered by fairway, rough, sand trap or green material in the final rendered model. Related patches of a surface (such as all of the sand traps) may be created as a single polyface mesh object for ease of materials application within a rendering program. In this example, the closed polylines representing the perimeters of the sand traps are selected within the Surface Region command, and a single polyface mesh entity is created consisting of just the sand traps. By creating and exporting (via DXF) polyface meshes representing like objects (green, fairway, sand trap, etc.), materials application within 3D Studio or AutoVision is fast and painless.

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Chapter 16: Creating 3D Studio meshes

Partitioning large surfaces

Quicksurf surfaces (TIN, TGRD, Grid) can easily exceed the face count limitations mentioned above. The Surface Region com-mand creates polyface mesh entities representing the surface within one or more closed polyline boundaries. If the boundary polyline contains the entire surface, the whole surface is repre-sented. If the surface would result in too many faces for a poly-face mesh (32,768), multiple adjacent polyface meshes are drawn each which fall within the face count limitation.

In such cases, simply draw a closed polyline which totally encompasses the surface and select it when prompted by the Sur-face Region command. The partitioning is automatic.

Morphing Quicksurf surfaces

3D Studio allows morphing between 3DS mesh objects contain-ing the same number of vertices. Quicksurf generated mesh objects may be used for morphing, if care is taken to insure that the meshes have the same number of vertices.

The safest way to insure morphable meshes is to create registered grid models using the same grid cell size with grid registration enabled. Use the same boundary and draw each different surface grid into the drawing as a polyface mesh. Export each mesh to 3D Studio using DXF. Each polyface mesh will have the same number of vertices in the same order, so 3D Studio will correctly morph the successive grid meshes.

For rendering purposes, in this special case, you may create grids even on surfaces containing break lines and get excellent results in the animated result.

Although TIN and TGRD models theoretically can be made mor-phable, it is not recommended, because the number and order of vertices is very difficult to control.

Morphing Quicksurf surfaces Page 325

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Chapter 17: User coordinate systems

Extract commands and User Coordinate Systems

AutoCAD supports both a World Coordinate System (WCS) and arbitrary User Coordinate Systems (UCS) which have rotated and/or translated coordinate axes. All of the Quicksurf Extract commands extract data in world coordinates by default, even if a UCS is in effect. Any entities shown or drawn by Quicksurf are displayed in the current coordinate system (UCS or WCS).

Under most circumstances with Quicksurf you will be extracting entities and displaying surfaces from the world coordinate system (WCS). If you display surfaces or contours from a UCS, they will be translated and/or rotated by the UCS coordinate system. This can be confusing if done by accident, but can be useful in special circumstances. For example, drawing from a UCS is use-ful for drawing contours on vertical planes, such as in fence dia-grams, or on the vertical exterior walls of block diagrams.

In special cases you may wish to extract drawing entities in UCS coordinates rather than WCS world coordinates. Drawing entities may be extracted in UCS coordinate space by using the COOR-

SYS keyword.

Command: QSOPTKeyword: COORSYSUse world coordinates <Y>: No

Remember to set COORSYS back to YES for normal use.

Change into the desired UCS and extract the data using one of the Quicksurf entity extraction commands, such as Extract to surface. The data will be extracted in UCS coordinates.

Extracting and displaying while in the same UCS will place the surfaces or contours where you expect them when COORSYS is set to NO. If COORSYS is set to YES, entities are always extracted in WCS coordinates.

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Chapter 18: Working with extracted contours

Objective

Create a surface by extracting elevation data from contour polylines in a drawing. Identify and correct surface irregularities caused by the non-uniform spatial distribution of points extracted from contour lines.

Existing contour polylines may be extracted from the drawing to create a set of points defining a new surface. Contours by defini-tion are lines of equal elevation and are normally represented as 2D polylines in the drawing. Each contour polyline must be at its appropriate elevation. This means the 100 meter contour polyline has Z = 100, the 200 meter contour polyline has Z = 200, etc. Extract to surface creates a point set consisting of the vertices of all selected contour polylines.

Workflow

• Verify that the source contour polylines in the drawing are their appropriate elevations. The Quicksurf elevation utilitiecommands will display or change 2D polyline elevations.

• Use Extract to surface to create a surface by extracting the contour polylines. Do not select extraneous drawing entiti

• Choose an appropriate grid cell size. You may want to usthe automatic settings for the first pass, then adjust the cesize later using the Surface options -> Cell size command.

• Choose to contour on the grid in most situations or contouon the TIN for dense contours using Configure contour.

• Show the contours.

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• Identify any problem areas. Common problems are slopeexcursions due to very close points at different elevations,gaps in the extracted contour polylines, or short-cutting cotours in areas of tight V-shaped contours.

• Correct any of the problems as described in the following tutorial and recreate the surface.

Extracted contours tutorial

Extracting the contours

This tutorial assumes you are starting with a set of drawn contour polylines.

First verify that the contour polylines in the drawing are at theiappropriate elevation.

Utilities -> Elevation utilities -> Display Z of entitySelect objects: select polyline and its elevation is displayed

Sequentially touch as many contour polylines as needed to cofirm their elevations. Press a return to exit Display Z.

If you need to move one or more contour polylines vertically tothe proper elevation use Change Z of entity in the same utilities menu.

Next extract the contour polylines to create a new <.> surfaceis very important that all the entities you extract are at the proelevation. The most common mistake is to extract extraneousentities such as text or labels which are not at the appropriateface elevation. Either freeze or turn off all layers not containinthe contours or use the filter capabilities invoked by checking Entity filter check box in the Configure extract dialog.

Extract the contour polylines using

Extract -> Extract to surface

If entity filters are selected you will see the following dialog.

Page 330 Extracted contours tutorial


Entity filter dialog before and after selection

By picking the polyline entity type, then pressing the Select but-ton, only polyline entities will be processed during the extract. Any combination of entity types may be selected. Pressing Reset displays the complete entity list.

Correcting slope problems

Slope problems with extracted contours are no different than any other curvature induced slope excursion. The root cause is two points which are close together yet differ in elevation, producing a steep local slope. With extracted contours this is commonly due to digitizing errors or extracting entities which are unrelated, such as text contour labels which may be at the wrong elevation (typically zero). The surface editing chapter covers techniques on correcting slope excursions. Most problems with extracted con-tours relate to mistakenly extracting the wrong entities.

Correcting short-cutting contours

In areas of V-shaped contours, Quicksurf may produce contours which short-cut the V-shape of the original contour. This will occur along sharp stream valleys or sharp ridges, or on data sets with widely spaced original contour polylines. The reason for this has to do with the point distribution fed to Quicksurf as input data.

Extracted contours tutorial Page 331


At the apex of the V-shape, all of the nearby data points are at the same elevation because they came from the vertices of the same contour polyline. This results in all of the vertices of the TIN tri-angles being at the same elevation, hence producing a flat trian-gle. The figure below illustrates flat spots.

Potential flat spot problems with extracted contours

The problem results from the fact that each contour polyline is highly sampled (at each vertex), but the distance between adja-cent contour polylines is comparatively huge. The clusters of points at V-shaped are all at the same elevation, resulting in a locally flat area.

The solution is to add data points between contours in these areas to give Quicksurf additional slope control. This would be tedious if you had to specify elevations for each point. There is a rela-tively easy technique supply the required slope information.

Consider the V-shaped contours of a stream drainage which exhibit local flat spot behavior. The missing information to cor-rect the problem is the 3D path of the stream bottom. By snapping a 3D polyline vertex to vertex from one contour to the next con-tour along the bottom of the drainage, you can supply the 3D path of the stream bottom. By using ENDpoint object snap mode on the original drawn contour polylines, you can build the 3D polyline without keying in any elevation data.



A snapped 3D polyline corrects the surface

If we used Merge extract directly, we would just extract the verti-ces of the 3D polyline we drew. We need to add additional points along the 3D polyline to the surface, not just its defining vertices. This is accomplished by using the Densify during extract option selected in the Configure extract dialog. This will interpo-late along the 3D polyline, providing the points we need to accu-rately describe the surface.

Command: OSNAPObject snap modes: Endpoint

Command: 3DPolyFrom point: select the contour vertex at the apexClose/Undo/<Endpoint of line>: select each contour at the apexClose/Undo/<Endpoint of line>: press enter to finish the command

Command: OSNAPObject snap modes: None

Configure ExtractSelect the Densify during extract check box and specify a step size.

Extracted contours tutorial Page 333


Extract -> Merge extractReturn to select all orSelect objects: select the new 3D polyline(s)

ContourSurface name <.>: Press enter None/Show/Draw/Redraw <Show>: S

The new surface will now honor the stream valley or ridge line properly. Notice that we did not select the 3D polyline as a break line, so we maintained surface curvature through the stream bot-tom. Using Extract breaks, rather than Merge extract, would have produced a knife-edged valley (or ridge line).

Edge effects

Anomalous behavior is common at the very edge of a surface. If you need a well behaved surface to the absolute edge of your data or beyond, supply a few additional data points to extend the sur-face. Use Track Z to estimate surface elevation for the points and draw new points with the AutoCAD POINT command. Short dis-tance extrapolation may also be accomplished with the Extrapo-late command. Add the new points to the surface with Merge extract. Refer to the surface editing chapter for step by step com-mands to merge the new data points.

You may want to use a boundary to limit the display of the sur-face to within the area of the original control points. The Tin Edge command found under the Quicksurf utilities menu can draw a polyline which follows the TIN edge for use as a bound-ary, if desired. The TIN edge boundary should be drawn prior to merging the new data points into the surface.


Chapter 19: Pad construction

Objective

Create a building pad cut into a hillside. Starting with the pad perimeter, construct the daylight lines representing the head of the cut and the toe of the fill. Create a contour map of the fin-ished design. Calculate the volume of cut and fill based on your new design.

Finished contours for building pad

The pad perimeter refers to the 2D or 3D polyline which describes the control line for slope projection. The daylight line is the 3D polyline where the projected slopes from the pad perim-eter intersect the existing topography. In this example we will only calculate volumes within the daylight line, because this is the only area where the existing and proposed design surfaces dif-fer in elevation.

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Workflow

• Create a surface representing the existing topography in tarea where the pad will be placed. Show the contours.

• Use surface operations to save the surface to Existing.

• Create a new current layer for your design.

• Determine the design elevation for the pad using Track Z.

• Draw the pad perimeter as a polyline at design elevation.

• Use Intersect slope to draw the daylight lines based upon thperimeter polyline and the slopes you specify.

• Draw an outer boundary rectangle containing the entire si

• Select the outer boundary rectangle and the daylight line anested boundaries using Set boundary.

• Draw the points using Points / Draw. This will draw the points of the existing topography outside the disturbed are

• Disable the boundary using Set boundary / Disable.

• Turn off all but the design layer. This layer should containpoints of the undisturbed topography, the pad perimeter polyline and the daylight line created by Intersect slope.

• Use Extract to surface to extract the points only. The filters of Configure extract can make this easy to do.

• Use Extract breaks to extract all of the pad and daylight polylines.

• Use TGRD to create your new design surface.

• Show the contours the design surface. Be sure that Configure contour is set to contour on the TGRD.

• Use surface operations to save the surface to Proposed.

• Use Area volumes to calculate the volume between Existing and Proposed surfaces, selecting the daylight line as the arpolyline.

Page 336 Workflow


Pad construction tutorial

We will use the Existing surface in the \QS51\DEMO5.QSB file as our base topography on which to build the pad. Load the file using the Read QSB button in the Surface Operations dialog.

Zoom the view so it overlies the surface and show the contours:

View options -> Surface viewSurface <.>: Existing

ContourSurface <Existing>: enterNone/Show/Draw/Redraw <Show>: enter

Create a new current layer named PAD for your design.Determine the design elevation for the pad using Track Z.

Utilities -> Elevation utilities -> Track ZSurface <Existing>: Existing

Draw the pad perimeter control line at the design elevation

Pad construction tutorial Page 337


Investigate the surface elevations on the gentle slope in the lower right quadrant of the contours as shown in the previous figure. Note the elevation at which to place the pad perimeter outline. Draw the pad perimeter as a 2D polyline at the chosen design ele-vation.

Command: ELEVNew current elevation <0.00>: 540 (use the design elevation)New current thickness <0.00>: 0

Command: PLINEFrom point: draw a closed polyline representing the pad perimeter.

The pad perimeter polyline intersects the surface as shown.

Oblique view of pad perimeter outline

Use Intersect slope to draw the daylight lines based upon the perimeter polyline and the slopes you specify.

Design Tools -> Intersect Slope

Surface name <Existing>: press enterSelect control linesReturn to select all orSelect objects: select pad perimeter polyline you drewSetup dialog <Y>: Yes to access Configure Slopes dialog

The slope specifications from this configuration dialog control the behavior of the Intersect slope command.

Page 338 Pad construction tutorial



Select Both in the Direction box to project up or down from the control line as necessary to intersect the surface. Select the Select point potion in the side control box to interactively pick from which side of the control line to project the slope. Use the defaults of auto step size and 45 degree slopes as shown. Press OK to exit the dialog.

Resulting 3D polylines from Intersect Slope



Draw an outer boundary rectangle containing the entire site. Show the TIN if needed to determine surface extents.

Command: RECTANGFirst corner: encompass entire surface

Select the outer boundary rectangle and the daylight line as nested boundaries

Boundary Options -> Set boundaryReturn to select all or Select objects: select both rectangle and daylight line drawn by ISLOPE

Draw the points. This will draw the points of the existing topog-raphy outside the disturbed area.

PointsSurface <Existing>: enterNone/Show/Draw/Redraw <Draw>: enter

Delete the boundary from memory. Remember, once a boundary is selected it is independent of its parent entity, so we must use the Boundary command, not just delete the parent polyline.

Boundary Options -> Set boundaryShow/New/DIsable/Enable/DElete/Read/Write <DI>: DEBoundary Deleted

Turn off all but the design layer. This layer should contain points of the undisturbed topography, the pad perimeter polyline and the daylight line created by Intersect slope.

We will Extract to surface to extract the points only. The filters of Configure extract can make this easy to do. Select the Config-ure Extract dialog and select the Filter by entity check box and exit.




The Entity filter dialog pops up. Highlight Point in the pick list then press Select. Only point entities will be extracted.The Extract to surface command will continue with

Return to select all orSelect objects: select by crossing all points and break lines.

Use Extract breaks to extract all of the pad perimeter polyline and the daylight polyline.

Extract -> Extract Breaks

The Entity filter dialog pops up. Press Reset to bring back the complete entity list then press OK. Extract Breaks will not use the points, so no entity filtering is required. The Extract Breaks command will continue with

Return to select all orSelect objects: select the daylight line and the pad perimeter polyline

Use TGRD to create your new design surface.

Triangulated gridSurface <Existing>: enter a period ’.’ to select the results <.> surfaceNone/Show/Draw/Redraw <Show>: enter

Invoke the Configure contour dialog and set it to contour on the TGRD. Now show the resulting contours.

ContourSurface <.>: enter None/Show/Draw/Redraw <Show>: enter

Use Surface operations to invoke the dialog, then highlight the <.> surface and press the Copy button and enter Proposed in the new surface name edit box.

You may want to use VPOINT or DVIEW to view the TGRD of the Proposed surface from various oblique angles.



Use Area volumes to calculate the volume between Existing and Proposed surfaces, selecting the daylight line as the area polyline. Area volumes will subtract (Proposed - Existing) and report the volumes of the resulting <.> surface.

Area volumes dialog box

After specifying the surface names in the dialog, press OK and you are prompted to select an area polyline within which to calcu-late the volume. Select the daylight line which was drawn by Intersect Slope. This represents the edge of the disturbed area in which the volume needs to be calculated. The volumes are dis-played on the text screen and optionally written to a text or data-base file.

The positive volumes represent fill and the negative volumes rep-resent cut. You should always visually examine the resulting thickness surface which is left in the <.> surface. This can be done quickly by showing the TIN from an oblique angle. If you enable the current boundary (set by area volume), just the areas which were calculated will be displayed upon displaying the TIN.


Chapter 20: Pond construction tutorial

Objective

Create a small pond sunk into existing topography. Starting with the pond surface perimeter and the estimated pond bottom eleva-tion, create the perimeter of the bottom of the pond. Create a con-tour map of the finished design. Calculate the volume of earth removed. Calculate the volume of the pond at various water ele-vations.

Pond triangulated grid

Pond finished contours

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In this case we are just sinking the pond into the surface and removing the earth. This example demonstrates the use of drape to convert a 2D plan view outline into a 3D polyline pond perim-eter daylight line. This is used as the control line for slope projec-tion to determine the perimeter where the projected slopes intersect the sloping bottom of the pond.

Workflow

• Create a surface representing the existing topography in tarea where the pond will be placed. Show the contours.



• Draw the pond perimeter as a 2D polyline.

• Drape the pond perimeter polyline onto the Existing surface.

• Use Build surface to create a sloping pond bottom surface.

• Use Intersect slope to draw the pond bottom perimeter polyline by projecting a slope down from the surface perimter polyline to the pond bottom surface.

• Draw an outer boundary rectangle containing the entire si

• Select the outer boundary rectangle and the pond surfaceperimeter as nested boundaries using Set boundary.

• Draw the points using Points / Draw. This will draw the points of the existing topography outside the disturbed are

• Disable the boundary using Set boundary / Disable.

• Turn off all but the design layer. This layer should containpoints of the undisturbed topography, the pond surface perimeter and bottom perimeter polylines.

• Use Extract to surface to extract the points only. The filters of Configure extract can make this easy to do.

• Use Extract breaks to extract the two perimeter polylines.

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• Show the contours the design surface. Be sure that Configure contour is set to contour on the TGRD.


• Use Area volumes to calculate the volume between Existing and Proposed surfaces, selecting the pond surface perimetas the area polyline. This is the volume of earth removed.

• Use Area volumes to calculate the water volume between Proposed surface and a constant elevation representing thwater level, selecting the pond surface perimeter as the arpolyline. Repeat for other water level elevations.

Pond construction tutorial

We will use the Swale surface in the \QS51\DEMO5.QSB file as our base topography in which to build the pond, but we will rename it to Existing for consistent terminology. Load the file using the Read QSB button in the Surface Operations dialog. While still in the dialog box, highlight the Swale surface name and press Copy button and copy the swale surface to Existing because it is our existing topography.

Zoom the view so it overlies the surface and show the contou



Create a new current layer named POND for your design.

Pond construction tutorial Page 345


Draw the pond perimeter as a 2D polyline as shown.

Location of pond outline

Drape the pond perimeter polyline onto the Existing surface. This surface must have at least a TIN to drape upon. When we showed the contours, we created a TIN, Derivatives and Grid automati-cally.

Design Tools -> DrapeSurface <Existing>: enterSelect objects: select the pond perimeter polyline

The pond perimeter is now a 3D polyline lying on the surface. Use Track Z to determine the existing surface elevation so you can estimate the desired pond bottom elevation.

Utilities -> Elevation utilities -> Track ZSurface <Existing>: Existing

Move the cursor over the surface to determine the original eleva-tion and decide on the pond bottom elevation. Press return to exit Track Z. We will use Build surface to create a sloping pond bot-tom surface. Build surface requires a few points or lines for input, so we will draw three points on the pond bottom to define the sloping pond bottom plane. Draw three defining points for the pond bottom. Use the .xy filter to graphically pick the point location, then enter the z value at the prompt.

Page 346 Pond construction tutorial


Command: POINT

Point: .xy <enter> of <pick point>(need Z) enter pond bottom elevation

Repeat for other two pond bottom defining points.

Pond perimeter and bottom defining points

Now build a temporary construction plane representing the pond bottom.

Design Tools -> Build surfaces

Build surfaces dialog

Press the Select Window button and graphically pick a window in which to create a temporary sloping planar surface represent-ing the pond bottom. Be sure the surface is much larger than the pond perimeter you have drawn. This surface will be used by Intersect slope to project the slope from the perimeter polyline to



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create the pond bottom polyline. Select Plane - 3 points and click on OK. You will be prompted to select the three defining points. Use the NEArest object snap when prompted for each point. This allows you to snap exactly to each point you have drawn. Build surfaces will now create a planar surface within the window you specified which passes through the points you selected. The surface will already have a TIN and reside in the results <.> surface. Erase the three points, so you don’t accidtally select them later.

Use Intersect slope to draw the pond bottom perimeter polyline by projecting a slope down from the surface perimeter polylinethe planar pond bottom surface in the <.> surface.

Design Tools -> Intersect SlopeSurface name <Existing>: press ’.’ to use the results surface, then enterSelect control linesReturn to select all orSelect objects: select pond perimeter polyline you drewSetup dialog <Y>: Yes to access Configure Slopes dialog




Select either Both or Down in the Direction box to project down from the control line to intersect the temporary planar pond bot-tom surface. Select the Select point potion in the side control box to interactively pick from which side of the control line to project the slope. Use the defaults of auto step size, but select 30 degree slopes as shown. Press OK to exit the dialog.

The resulting 3D polyline is shown on the next page. Your result may look different depending upon the elevation of your pond bottom and the slopes you used. If your pond bottom is too deep or your slope too shallow, the resulting polyline may cross itself and be useless. Increase the slope or raise the pond bottom in such cases.

Pond perimeter and 3D polylines created by Intersect slope

We need to draw the points representing the undisturbed existing topography back into the drawing. Draw an outer boundary rect-angle containing the entire site. Show the TIN, if needed, to determine surface extents.

Command: RECTANGFirst corner: encompass entire surface

Select the outer boundary rectangle and the daylight line (pond perimeter) as nested boundaries.



Boundary Options -> Set boundary

Return to select all or Select objects: select both rectangle and pond perimeter polyline

Draw the points. This will draw the points of the existing topog-raphy outside the disturbed area.


Delete the boundary from memory. Remember, once a boundary is selected it is independent of its parent entity, so we must use the Boundary command, not just delete the parent polyline.

Boundary Options -> Set boundary

Show/New/DIsable/Enable/DElete/Read/Write <DI>: DEBoundary Deleted

Turn off all but the design layer. This layer should contain points of the undisturbed topography, the pond perimeter polyline and the pond bottom polyline created by Intersect slope.



The Entity filter dialog pops up. Highlight Point in the pick list then press Select. Only point entities will be extracted.The Extract to surface command will continue with




Use Extract breaks to extract all of the pond perimeter polyline and the pond bottom polyline.





Return to select all orSelect objects: select the two pond defining polylines


Triangulated gridSurface <Existing>: enter a period ’.’ to select the results <.> surfaceNone/Show/Draw/Redraw <Show>: enter

Invoke the Configure contour dialog and set it to contour on the TGRD. Now show the resulting contours.

ContourSurface <.>: enter None/Show/Draw/Redraw <Show>: enter

This should look similar to the first figure in this chapter showing the contoured pond.


You may want to use VPOINT or DVIEW to view the TGRD of the Proposed surface from various oblique angles.

Use Area volumes to calculate the volume between Existing and Proposed surfaces, selecting the pond perimeter as the area polyline. Area volumes will subtract (Proposed - Existing) and report the volumes of the resulting <.> surface.



Area volumes dialog box

After specifying the surface names in the dialog, press OK and you are prompted to select an area polyline within which to calcu-late the volume. Select the pond perimeter polyline. This repre-sents the edge of the disturbed area in which the volume needs to be calculated. The volumes are displayed on the text screen and optionally written to a text or database file.

The negative volumes represent volume of earth removed to cre-ate the pond. You should always visually examine the resulting thickness surface which is left in the <.> surface. This can be done quickly by showing the TIN from an oblique angle. If you enable the current boundary (set by area volume), just the areas which were calculated will be displayed upon displaying the TIN.

Use Area volumes to calculate the water volume between Pro-posed surface and a constant elevation representing the water level, selecting the pond perimeter as the area polyline. This is accomplished by selecting the Constant check box in the Area volumes dialog and entering the water level elevation in the adja-cent edit box. The negative volume represents the water volume for the different water levels. This is due to (Proposed - Con-stant) being a negative number. Proposed represents the pond bottom and Constant represents the water level. The positive vol-


ume is meaningless, as it represents the volume of earth between the water level elevation and the earth surface inside the pond perimeter polyline.

Repeat for other water level elevations.

Page 354 Quicksurf

Chapter 21: Ditch construction

Objective

Create a ditch cut into existing topography. Starting with the ditch centerline and create a narrow flat bottomed ditch. Create a contour map of the finished design and calculate the volume of earth removed.

Triangulated grid of ditch

In this example, we are simply sinking the ditch into the surface and removing the earth. This example demonstrates the use of offset, drape and move commands to create the 3D polylines of the ditch edges (daylight lines) and ditch floor. A different drape step will be used when creating the ditch edge and ditch floor polylines.

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Workflow

• Create a surface representing the existing topography in tarea where the ditch will be placed. Show the contours.



• Draw the ditch center line as a 2D polyline in plan view.

• Offset the centerline for the ditch edge and bottom polyline

• Drape these onto the Existing surface.

• Move the ditch bottom polyline vertically down to depth.

• Draw the points using Points / Draw.

• Erase any points within the ditch borders ( Erase using the window polygon option)

• Turn off all but the design layer. This layer should containpoints of the undisturbed topography and the ditch polyline

• Use Extract to surface to extract the points only

• Use Extract breaks to extract the ditch polylines.


• Show the contours the design surface. Be sure that Configure Contour is set to contour on the TGRD.


• Use Area volumes to calculate the volume between Existing and Proposed surfaces, selecting the ditch perimeter as thearea polyline. This is the volume of earth removed.

Page 356 Workflow


Ditch construction tutorial

We will use the Existing surface in the \QS51\DEMO5.QSB file as our base topography for a flat-bottomed ditch. Load the file using the Read QSB button in the Surface Operations dialog.




Create a new current layer named DITCH for your design.Draw the ditch center line as a 2D polyline in plan view as shown.

Plan view of proposed ditch centerline

Ditch construction tutorial Page 357


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Offset the centerline for the ditch edge and bottom polylines.

Command: OFFSETOffset distance or Through <Offset> : 8 (8 foot offset)Select object to offset: select centerlineSide to offset: pick a point on one side of the centerlineSelect object to offset: select centerlineSide to offset: pick a point on the other side of the centerlineSelect object to offset: press return to exit offset command

Repeat with a 3 foot offset for the ditch bottom polylines, then erase the centerline.

Offset polylines for the ditch edges and bottom

Drape the outer two polylines onto the Existing surface.

Design Tools -> DrapeSurface <Existing>: enterSelect objects: select the outer two ditch polylines

These two polylines are draped using the Auto setting for drape step. Let’s investigate the effect of manually setting a relativellarge drape step. Recall that drape step is segment length thaline or polyline is divided into when creating a draped 3D

Page 358 Ditch construction tutorial


polyline. The Auto setting densifies the draped lines so they fol-low the surface closely. By setting a large drape step we can cause linear segments in the ditch bottom equaling the drape step length. Invoke the Configure Drape dialog and select the Drape on the TIN with Derivatives and set a drape step of 50. Exit the dialog.

Design Tools -> DrapeSurface <Existing>: enterSelect objects: select the inner two ditch bottom polylines

Move the draped ditch bottom polylines vertically down to depth.

Command: MOVESelect objects: select the inner two ditch bottom polylinesBase point or displacement: 0,0,-10 (this is the displacement down)Second point of displacement: press enter

Now the break lines are at their proper positions in space.

Ditch bottom and end lines

To minimize edge effects, draw a lines (or 3D polyline) connect-ing the ends of the four ditch polylines.

Command: OSNAPObject snap modes: ENDPOINT

Command: LINEFrom point: select end of one outer ditch edge polylineTo point: select end of nearest ditch bottom polylineTo point: select end of other ditch bottom polylineTo point: select end of last ditch edge polylineTo point: press enter to exit



Draw the points of the existing surface into the drawing.


Erase any points within the outer daylight lines of the ditch. This is important, because you do not want any of the existing control points within the area disturbed by your design.

Command: ERASESelect objects: enter WP for window polygon selectionFirst polygon point: selectUndo<Endpoint of line>: pick multiple locations following the ditch edge

(don’t erase the polylines, just the points)Undo<Endpoint of line>: press enter when done

Turn off all but the design layer. This layer should now contain points of the undisturbed topography, the four draped ditch polylines and the end break lines.



The Entity filter dialog pops up. Highlight Point in the pick list then press Select. Only point entities will be extracted. The Extract to surface command will continue with


Use Extract breaks to extract all of the ditch polylines.





Return to select all orSelect objects: select the ditch and end polylines


Triangulated grid

Surface <Existing>: enter a period ’.’ to select the results <.> surfaceNone/Show/Draw/Redraw <Show>: enter

Use the Surface view command to examine the TGRD.


Set the camera height to 40 and press OK to exit the dialog.

View Options -> Surface viewSurface <.>: enter Viewing position: pick a point at one end of the ditchViewing direction: pick a point at the other end of the ditch

The view will change to a perspective view using DVIEW. Show the TGRD again.

Triangulated grid of ditch



If you wish to contour the surface, set Configure contour to con-tour on the TGRD, then show the contours from plan view.


Use Area volumes to calculate the volume between Existing and Proposed surfaces, selecting the daylight line as the area polyline. Area volumes will subtract (Proposed - Existing) and report the volumes of the resulting <.> surface. This sequence is identical to that used in the preceding tutorials.


Chapter 22: Wall construction

Occasionally in site design you will need to represent vertical walls or curbs. A surfaces containing a wall may either be repre-sented in three pieces (upper surface, vertical wall, and separate lower surface) or represented a single surface with the wall top and base offset by a very small distance.

Nearly vertical surfaces

Page 363


Vertical discontinuities

Recall that the Quicksurf definition of a surface is a single-valued function of the independent variables x,y. This means that no part of a surface may be vertical, since it would have more than one elevation value at a given x,y point.

However, the steepest surface Quicksurf can model is one in which the upper and lower edges are displaced by approximately

drawing units, which is indistinguishable from vertical in most cases.

For example, assume you draw a 3D polyline, then copy it with a displacement of (0,0,5) to create the top and base of a proposed wall. If you extract these polylines with Extract Breaks, the resulting vertices will exactly above one another and therefore one set will be dropped as stacked points. This will not yield the desired surface. Instead, offset the polyline laterally a small amount as well as vertically. When extracted as break lines, these polylines avoid stacked points and produce one continuous sur-face which properly represents the wall and the surfaces on either side. In practice, offsetting the top and base of the wall by 0.1 foot works well and is volumetrically insignificant.

If you are creating designs containing stone, concrete or wood walls, the Imagine Detailor series of tools from Schreiber Instru-ments, inc. can speed your geometric design and rendering signif-icantly.

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Page 364 Vertical discontinuities


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Workflow

To model a vertical object (like a building wall), follow these steps:

• Draw a 2D or 3D polyline representing the upper edge of tvertical surface at the desired elevation.

• Use the 3D Offset command to make a copy of the polyline displaced very slightly in an appropriate horizontal directioand vertically by the wall height. Move, Drape, and Offset may also be useful tools here.

• Load the defining points for the surface (not including the wall) to create a new surface.

• Extract both 3D polylines as break lines with Extract breaks.

• Use TGRD to create and display the surface.

Workflow Page 365

Quicksurf

Chapter 23: Road construction

Objective

Create a road across existing topography. Starting with the road centerline and a road cross-section, create all of the break lines for the road, ditches and daylight lines. Create a triangulated grid reflecting the new design. Create a contour map of the finished design and calculate the cut and fill volumes.

Triangulated grid of a roadway

In this example, we are starting with an existing topographic sur-face, and a plan view road centerline. This example demonstrates the use of the drape, flatten, vertical align and apply section com-mands to create the 3D polylines of the roadway components and the edge of the disturbed area (daylight lines).

Objective Page 367


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Workflow

• Create a surface representing the existing topography in tarea where the road will be placed. Show the contours.



• Use Points / Draw to draw the existing control points.

• Draw the roadway center line as a 2D polyline in plan view

• Drape this onto the Existing surface.

• Use Flatten to create a 2D centerline vertical profile.

• Draw new vertical road profile on the above profile graph.

• Use Vertical align to apply the new vertical profile to the draped line which represents the horizontal alignment.

• This new 3D pline will be the control line for Apply section.

• Draw the road cross-section template(s) as 2D polylines.

• Use Apply section to build the road break lines.

• Use Extract to Surface for the undisturbed topo entities.

• Use Extract breaks for the road break lines.

• Use TGRD to build the new surface.

• Show the contours the design surface. Be sure that Configure Contour is set to contour on the TGRD.


• Use Area volumes to calculate the volume between Existing and Proposed surfaces, selecting a road perimeter polyline the area polyline.

Page 368 Workflow


Road construction tutorial

Loading the existing topography

We will use the Existing surface in the \QS51\DEMO5.QSB file as our base topography for building a road. Load the file using the Read QSB button in the Surface Operations dialog. Press OK.

Next invoke the Configure Grid dialog box and set Cell count to 50 for both X and Y directions.




Drawing the topo control points

Create a new current layer named ROAD for your design. Draw the points of the existing surface into the drawing. Apply Section will automatically move the original points in the disturbed area (between the daylight lines) to another layer. To take advantage of this feature the points defining the existing topography must be drawn into the drawing.

PointsSurface <Existing>: enterNone/Show/Draw/Redraw <Show>: Draw

Drawing the plan view road

Draw the road centerline from left to right as a 2D polyline in plan view as shown. Be careful not to draw the centerline off the edge of the defined surface (the contoured area).

Road construction tutorial Page 369


Plan view of proposed roadway centerline

Creating the 3D centerline polyline

Drape the road centerline polyline onto the Existing surface.

Design Tools -> DrapeSurface <Existing>: enterSelect objects: select the road centerline 2D polyline

The draped polyline represents the horizontal alignment of the road as a 3D polyline at the elevation of the existing topography. The next step is to display, then adjust the vertical profile of this centerline to reflect the design profile.

Creating the 2D centerline profile

Next Flatten the draped 3D polyline to create a 2D profile of the existing topography along the proposed road. Flatten expects polylines drawn left to right. You may use the Swap ends com-mand to reverse any 3D polylines which are drawn in the wrong direction prior to using Flatten.

Page 370 Road construction tutorial


Design Tools -> Flatten

Return to select all visible orSelect objects: select horizontal alignment (draped centerline polyline)

Vertical multiplier <2>: enterText size for labeling <15>: enterBase elevation for grid / Auto <Auto>: enterDraw grid background <Yes>: enterVertical spacing <20>: enterVertical labeling interval <2>: enterHorizontal spacing <40>: enterHorizontal labeling interval <5>: enter

Origin: select point representing the lower left corner of the profile to be drawn. Place this above your map area.

Flattened 2D profile of the road centerline (2X vertical)

Drawing the new vertical alignment

Next we will draw the proposed vertical alignment of the road-way centerline right on top of the flattened 2D profile.

The road grade has been exaggerated for clarity.

New vertical profile of the road centerline



Applying the vertical alignment to the 3D centerline

Vertical align will adjust the horizontal profile (the draped road-way 3D polyline) to reflect our new design vertical profile we have just drawn in the above figure.

Design Tools -> Vertical align

Select vertical alignment...Return to select all visible orSelect objects: select adjusted vertical profile 2D polylineSelect base point: snap to lower left corner of 2D profile graph axesSet elevation of base point <default>: enter elevation (460) of base pointVertical multiplier <1>: 2 (factor used when creating 2D profile)Select horizontal alignments for applying vertical alignment...

select centerlineErase original horizontal alignment polyline? <Yes>: enterNone/Show/Draw/Redraw <Show>: DrawApplying new vertical alignment...

At the first select prompt, select the newly-created 2D adjusted vertical profile polyline that will provide the vertical alignment. At the base point prompt, snap to the point representing the origin of the vertical alignment graph created by Flatten. Supply the elevation of this point (460 in this example). At the vertical multi-plier prompt, enter the same vertical multiplier (2) used when cre-ating the flattened profile.

Finally, select the horizontal alignment polyline which is the draped roadway centerline. A new 3D polyline will be created having the original horizontal alignment with the Z values of its vertices adjusted to reflect the new vertical alignment. You are prompted whether to erase the original horizontal alignment polyline. Answer Yes to delete the original, leaving just the design 3D polyline centerline.

We are in plan view, so we cannot see the changes to the road centerline because they are all in the Z dimension. Apply section will sweep a road cross-section template along this design center-line and create all necessary break lines. Each vertex in the cross-section polyline creates one break line, similar to extrusion.



Creating the cross-section template

A cross-section template is a 2D polyline, drawn in the XY plane, representing the road cross-section. This polyline is swept along the control line to produce a set of 3D polylines, one for each ver-tex of the cross-section. Two additional 3D polylines are created representing the intersection of the slope projected from the end points of the cross-section polyline and the topographic surface. These 3D polylines will be used as break lines when creating the new design surface.

Cross-section template of roadway

Command: PLINEFrom point: select a point to the side of your mapArc/Close/Halfwidth/Length/Undo/Width/<Endpoint of line>: @3,-1Arc/Close/Halfwidth/Length/Undo/Width/<Endpoint of line>: @3,1Arc/Close/Halfwidth/Length/Undo/Width/<Endpoint of line>: @20,1Arc/Close/Halfwidth/Length/Undo/Width/<Endpoint of line>: @20,-1Arc/Close/Halfwidth/Length/Undo/Width/<Endpoint of line>: @3,-1Arc/Close/Halfwidth/Length/Undo/Width/<Endpoint of line>: @3,1Arc/Close/Halfwidth/Length/Undo/Width/<Endpoint of line>: enter

Running Apply Section

The complete command dialog sequence is show on the next page for Apply section. Each part is described individually in the text which follows.



Design Tools -> Apply section

Invokes Configure Slopes dialog to set slopes and transitions.

Surface <current>: select or press ? to pick from surface listSelect starting section...Select objects: select cross-section templateControl line point on starting cross-section: select point using osnapUse a different ending section <N>: enterSelect control line: selectApply to entire Control line or Segment <C>: enter None/Show/Draw/Redraw <Show>: DApplying cross-section...Finished

Apply section invokes the Configure Slopes dialog box to control the slope behavior on either side of the road and transitions (if any) between different road cross-sections.

Setting the slope angles

At either end of the cross-section template, user-specified slopes are projected up or down until they intersect the surface. A 3D polyline is drawn representing this slope-surface intersection. These are commonly called daylight lines. Slope and transition control is specified in the Configure Slopes dialog box which is automatically invoked by Apply section. The complete descrip-tion of this dialog is Chapter 7 (page 225) on Configuring Quick-surf. For this tutorial set the slopes a shown below.



Intersect slope dialog for Apply section

Selecting the surface

Apply section will prompt for the surface name representing the existing topography. This surface is used to determine the day-light lines by projecting slopes from the ends of the cross-section template.

Surface <Existing>: enter

Selecting the cross-section template

Select starting section...Select objects: select cross-section template

Select the 2D polyline cross-section template you drew.



Attaching the cross-section to the control line

To sweep the cross-section along the control line we must specify how to attach the template to the control line. You are prompted to select a attachment point on the cross-section.

If you are unfamiliar with transparent zooms, consult your AutoCAD manual.

Control line point on cross-section: ’zoomAll/Center/Dynamic/Extents/Left/Prev/Vmax/Window/<Scale(X/XP)>: WFirst corner: pick window containing cross-section templateOther corner: pickControl line point on cross-section: Endpoint of (pick center point)

Conceptually, this represents the point on the cross-section which is "connected" to the control line as the cross-section is swept down the control line. Typically this will be a vertex or a mid-point on the 2D cross-section polyline. If so, use OSNAP to END-

point or MIDpoint to insure proper alignment. Although the attach-ment point is normally on the cross-section polyline, this is not required. The relative position between the cross-section polyline and the attachment point is used when applying the section.

If you were creating a transition between different cross-sections you would indicate so and select a second cross-section. In this example we will only use a single cross-section for the entire road.

Use a different ending section <N>: enter

Applying the cross-section

Apply section prompts for the control line, then creates the break lines and draws them to the current layer.

Select control line: ’ZoomAll/Center/Dynamic/Extents/Left/Prev/Vmax/Window/<Scale(X/XP)>: PSelect control line: select roadway centerlineApply to entire Control line or Segment <C>: enter None/Show/Draw/Redraw <Show>: DrawApplying cross-section...Finished



We are applying the section to the entire control line, so we answer C for Control line. If we only wanted to apply the section to a segment of the control line we could answer S and specify a segment graphically (by pointing) or numerically as beginning and ending distances from the beginning of the control line.

Break lines created by Apply section

The break lines are drawn by Apply section and any original (drawn) defining points of the existing topography within the dis-turbed area are moved to a new frozen layer called OLD_DATA. These break lines will be used in creating the new design topogra-phy. Apply section uses the step size in Configure Drape inter-nally, so if it seems to be running very slowly, insure that you have not set an unreasonably small step size. This tutorial is assuming the default configuration is being used.



Creating the new design surface

Turn off all but the design layer (Road). This layer should now contain points of the undisturbed topography and the break lines created by Apply Section.

We will use Extract to surface to extract the points only. The fil-ters of Configure extract can make this easy to do. Select the Configure Extract dialog and select the Filter by entity check box and click OK to exit the dialog. The entity filter will pop-up every time you perform an extract.


The Entity filter dialog pops up. Highlight Point in the pick list then press Select. The list reduces to contain only Point entities. Press OK to exit the pop-up list. Only point entities will be extracted. The Extract to surface command will continue with


Use Extract breaks to extract all of the roadway break polylines.


The Entity filter dialog pops up. Press Reset to bring back the complete entity list then press OK. Extract Breaks will not use the points, so no entity filtering is required. Select all break lines.



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The Extract Breaks command will continue with

Return to select all orSelect objects: select the break lines created by Apply Section

Using curve error of 0.9639 Break lines extracted

On complex break line sets, Auto densification will repeatedly triangu-late as it converges.

Auto densification...3838 triangles built4724 triangles built...4904 triangles built4908 triangles built4910 triangles built2317 additional points added to current surface


Triangulated grid

Be sure to select the <.> surface!

Surface <Existing>: enter a period ’.’ to select the results <.> surfaceAdding break line points...Creating grid points...Auto densification...8794 triangles built8814 triangles builtNone/Show/Draw/Redraw <Show>: enter

The triangulated grid of the new surface is displayed. The plan view is not very informative, so let’s try some other ways to sethe result.

Examining the new design surface

Use the Surface view command to examine the TGRD.


Set the camera height to 40 and press OK to exit the dialog.



View Options -> Surface view

Surface <.>: enter Viewing position: pick a point on the surface at the left end of the roadViewing direction: pick a point at the other end of the road

The view will change to a perspective view. Because the change of view performed a redraw, the shown TGRD disappeared. Show the TGRD again.

Triangulated grid

Surface <.>: enterNone/Show/Draw/Redraw <Show>: enter

Triangulated grid of road



Contour the surface, but first set Configure contour to contour on the TGRD, then show the contours from plan view.

View Options -> Surface plan view


Contours on the triangulated grid road surface

Calculating volumes

We will use Area volumes to calculate cut and fill volumes. Our design surface is in the <.> surface which will be overwritten by any surface operation. We need to save this surface to a named surface so we can use it for later display and calculation. Use Surface operations to invoke the surface operations dialog, then highlight the <.> surface by clicking on it, then press the Copy button and enter Proposed in the new surface name edit box.



We will calculate the cut/fill volumes under the disturbed area. To do so we must create a closed polygon (to use with Area Vol-ume) encompassing the design area between the outer daylight lines of our road. We will use the Create boundary polyline com-mand, which assembles lines and 3D polylines into one closed 3D polyline.

Creating the design area bounding polygon

At each end of the road, draw a line (not 2D polyline) from the endpoint of the outer left daylight line to the endpoint of the outer right daylight line. Use OSNAP to ENDPOINT to be sure you snap exactly to the endpoints of the outer daylight lines. After doing this you will have the two outer daylight lines and the two lines you just drew ready to create a bounding 3D polyline encompass-ing the design area.

Use Create boundary polyline to create the closed 3D polyline around the design area.

Utilities -> Polyline utilities -> Create boundary polylineSelect entities to create boundary...Return to select all orSelect objects: Select two outer daylight lines and two end linesNone/Show/Draw/Redraw <Show>: Draw

This will draw a new 3D polyline to use as an area polygon for use with Area Volumes.

Calculating cut and fill

Use Area volumes to calculate the volume between Existing and Proposed surfaces, selecting the 3D polyline you just drew as the area polylines. Area volumes will subtract (Proposed - Existing) and report the volumes of the resulting <.> thickness surface. You may show the TIN or contour this thickness surface. This sequence is identical to that used in the preceding tutorials.



Perspective view of resulting thickness <.> surface

The figure above shows the thickness surface computed by Area volume. The two long sides of the road design area are at an ele-vation (thickness) of zero because the existing surface and pro-posed surface are at the same elevation along this line. Positive areas represent fill and are reported as positive volumes. Nega-tive areas represent cuts and are reported as negative volumes.

Contour map of cut/fill thickness surface

By creating closed 2D or 3D polylines containing only portions of the roadway (such as between two stations), cut and fill vol-umes may be calculated with Area Volumes for any segment or group of segments.


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Chapter 24: Slope analysis

Objective

Analyze and display the slope distribution of a topographic sur-face. Create a surface display coloring each part of the surface by its slope. Create an iso-slope contour map and hachure areas within certain slope ranges.

Workflow

Surface slope display

• Create a surface representing the existing topography usingrid model. Use a TGRD if the surface contains breaks. Show the contours.

• Examine the surface by showing the TIN or TGRD from anoblique view using VPOINT and Surface zoom.

• Choose color by Slope in the Surface colors dialog.

• Select the Drawing legend check box.

• Press the Configure colors button to setup colors.

• Select the Use range check box and specify the slope rangeby specifying minimum and maximum slope values.

• Set the Number of colors to the number of intervals you would like to divide the slope range into

• Press the Set Interval button and confirm your intervals.

• Show or draw the grid. It will be colored by the slope intervals you specified.

Objective Page 385


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Iso-slope contour map

• Create a surface representing the existing topography usingrid model. Use a TGRD if the surface contains breaks. Show the contours from plan view.

• Use surface operations to save the surface to Topo.

• Use surface operation Degree slope to create a new <.> sur-face whose Z value is slope in degrees.

• Use Contour interval to set an appropriate contour interval. An appropriate contour interval would then be 1.0 for 1 degree contours; 5.0 for 5 degree contours, etc.

• Use Contour / Draw to draw the contours. Answer Yes to the Close all? prompt to allow for subsequent hatch filling. The Close all option is only available when contouring on the gri

• Use AutoCAD’s Hatch command and select adjacent con-tours to hatch areas within that slope interval.

Slope analysis tutorial

Surface slope display

This command sequence will create an isometric display of a topographic surface colored by slope. First load the standardconfiguration file so we have the same starting point:

Configuration -> Read ConfigurationRead options from file <drawingname>: QSReading options from file QS.QCF

We will read and use the Existing surface from the included file \QS51\DEMO5.QSB.

Surface operations

Page 386 Slope analysis tutorial


Select Read QSB and select DEMO5.QSB from the file dialog. This file is located in the \QS51 directory. This will load all of the example surfaces into surface memory. Next use Surface zoom to align the view over the surface.


Contour the surface to see the general shape.

ContourSurface<.>: ExistingNone/Show/Draw/Redraw <Show>: Show

Now examine the surface by showing the grid from an oblique view using VPOINT and Surface zoom.

Command: VPOINTRotate/ <View Point> <0.0000, 0.0000, 1.0000>: 1,-1,1Regenerating drawing

View Options -> Surface zoomSurface <Existing>: Existing

GridSurface<.>: ExistingNone/Show/Draw/Redraw <Show>: Show

By default the surface is colored by elevation, use The color options dialogs to choose color by slope in degrees.

Color options -> Surface colors

Within the Surface colors dialog, choose the color by Slope in Degrees checkbox. Press the Configure colors button to invoke the Surface Color Sequence dialog. The current color sequence is displayed. Select the Use range check box and specify the slope range by specifying 0 degrees as the minimum and 20 degrees as the maximum slope values. Set the Number of colors to 10, to divide the slope range (20 degrees) into 10 intervals of

Slope analysis tutorial Page 387


two degrees each. Press the Set Interval button to confirm your intervals. This will invoke the Surface Color Intervals dialog which displays the current interval settings. These are evenly spaced two degree intervals because we set a maximum and min-imum (0 and 20) and a number of intervals (10). Had we not set the maximum and minimum discretely, the actual range of the data is used which usually results in an odd interval. Press OK several times to exit the nested dialog boxes.


The grid will be colored by the two degree slope intervals you specified. You may want to experiment with changing the Num-ber of Colors setting to divide the slopes into finer intervals (try 20) or coarser intervals (try 5).

Enable the drawing legend check box.

Color options -> Surface colors

Within the Surface colors dialog, enable the Drawing Legend checkbox which will cause a legend to be displayed when the grid is shown or drawn. Press OK to exit the dialog.

Finally change back to plan view and display the grid with a smaller cell size

View Options -> Surface plan viewSurface <Existing>: Existing


Reducing the cell size of the grid makes the visual display appear more solid.

Surface options -> Cell Size



Surface name <Existing>: Press enter Current cell size is <37.21 x 36.86 > Horizontal cell size/Auto <default>: 10 Vertical cell size/Auto <default>: 10111 x 81 grid built


You may want to experiment with other surface color options while you have this example surface loaded. Surface coloration is a very powerful visualization tool.

Iso-slope contour map

An iso-slope contour map is another way of displaying a slope analysis. If you do not have the Existing surface loaded from the previous example, please load it as described in the Surface slope display tutorial a few pages back. We will create a new surface whose Z value is slope in degrees, rather than elevation, then con-tour it.

Surface operations

In the upper right quadrant of the Surface operations dialog, select Existing as the first surface, and Degree slope as the opera-tion, then press Run Operation. This will compute a new results <.> surface whose Z value is slope in degrees. Now set an appro-priate contour interval and draw the iso-slope contours.

Contour IntervalContour interval/Auto <Auto>: enter 2 for a 2 degree contour interval

ContourSurface<.>: ExistingNone/Show/Draw/Redraw <Show>: DrawClose all? <N>: Yes

Slope analysis tutorial Page 389


Answering Yes to the Close all? prompt produces contour polylines which are closed around the edge of the grid. This allows for subsequent hatch filling. The Close all option is only available when contouring on the grid.

Areas representing a range of slopes may be hachured by select-ing the two slope contours on either end of the slope range. In our example, we contoured using two degree slope increments, so selecting two contour polylines, such as the 8 degree and 10 degree contours, would hatch the area of the surface with slopes in that range.

Command: HatchPattern (? or name/U,style) <>: LineScale for pattern <>: 100Angle for pattern <>: 45Select objects: select two adjacent contour polylines

Repeat as necessary to hachure different slope areas with differ-ent hatch patterns. Hatch patterns are placed in the drawing as blocks at the current elevation. If you are creating a 3D model, you may wish to explode the hatch patterns blocks and drape them on the Existing topography surface (not the slope surface).

Some of the elevation utility routines supplied with Quicksurf such as Display Z of entity and Select by Z can be very useful in selecting contours to hatch between.

Iso-slope contour maps and colored surfaces (TIN, TGRD, Grid) (by slope) may be used alone or in combination to create effective slope analysis displays.


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Chapter 25: Contaminant modeling

Overview

Contaminant data sets are commonly characterized by a large range of z values. Many low concentration values may exist out-side of the contaminated area and a cluster of very high concen-tration samples may exist within the contaminated area. Several factors make these data sets different:

• Exponential surface behavior

• Large range in z values

• Extremely steep inter-point slopes

• Non-uniform spatial sampling (clustered samples in highs

• Relatively small number of points

Contaminant data is expensive to acquire, so sites typically haa minimum number of samples. The small number points combined with the very steep inter-point slopes are not compatiblewith the default method of Standard and Derivatives set to 2nd (continuous curvature). Depending on the input data set sevetechniques can help build meaningful surfaces for these data

Mapping contaminant iso-concentrations

If the data set you are working with has z values which range oseveral orders of magnitude, use Surface operations to take the natural logarithm (Ln) of the data points before creating a surface. This normalizes the z values into a more workable range and reduces the extreme slopes. Many times, simply taking the loprior to surface creation allows Quicksurf’s default continuouscurvature to produce acceptable concentration surfaces, but king generally produces better concentration surfaces than curture-based methods.

Overview Page 391


After creating a surface in logarithmic space, you may exponenti-ate it back to its original values if you need the actual concentra-tion contour labels, rather than Ln concentrations. Logarithmic contour labeling of 0.01, 0.1, 1.0, 10, 100, etc. may be accom-plished using and Elevation list file described in the Configure Contour section of the Chapter 7.


It is a good idea to examine the raw data set prior to creating any grid surface. Contouring based upon the TIN or showing the TIN from an oblique view displays the geometry of the data set using only linear interpolation. Once you have confirmed that the input data looks reasonable, you can proceed to design a variogram and create a grid by kriging.

Kriging

Kriging works well for modeling many concentration data sets. A very elementary background of kriging is discussed in the Vari-ogram design command description in Chapter 6. Kriging cre-ates a grid based upon the input data set and a variogram which defines the relationship between surface (z value) variance and horizontal distance. The resulting grid from kriging is utterly dependent upon proper variogram design. Without a proper vari-ogram, meaningless grids may be created.

Variogram design

Variogram defining parameters such as variogram type, nugget, range and sill may be specified in the Krige parameters section of the Configure Grid dialog or determined interactively using the Variogram design command. The shape of the variogram curve is reflected in the shape of the surface surrounding data points. Kriging works better than curvature based methods because the variogram may be designed incorporating knowledge about the behavior of the contaminant being mapped.

Page 392 Mapping contaminant iso-concentrations


There is an inherent Catch-22 in designing variograms for small concentration data sets: The interactive design of a variogram is based upon building a histogram of variance versus distance, then defining the shape of the variogram curve based upon this graph. Many contaminant concentration data sets consist of only a few dozen points, not enough to provide an adequate statistical basis to design a variogram. In practice, the variogram may be defined incorporating your knowledge of the contaminant transport behavior and the medium it is travelling through, rather than solely on the variance histogram alone.

Creating a Kriging-based grid

Once you have specified the variogram parameters either by entering them in the Configure Grid dialog or by using the Vario-gram design command, the grid may be created normally. Either the Grid command or Contour command (with Configure Contour set to contour on the Grid) will display the kriged surface.

The most common error using kriging is to use too short a range, which results in flat areas in between data points at the mean ele-vation of the data set. Kriging is very effective when properly applied, but is very prone to misuse due to lack of understanding by the user. If you plan to use kriging, take the time to read and understand the underlying theory. A simple tutorial and a few references are offered in the next chapter.

Mapping contaminant iso-concentrations Page 393

Quicksurf

Chapter 26: Using Kriging

Introduction

This chapter is an introduction for the practical use of kriging to build grids and contour maps. Kriging is a geostatistical method of surface estimation which was originally developed in the min-ing industry for ore reserve estimation. Proper use of kriging requires a conceptual understanding of the underlying statistical methods which is beyond the scope of this manual. There is con-siderable literature on kriging. Two good introductory references on kriging are

J. Davis. Statistics and Data Analysis in Geology. John Wiley and Sons, New York, NY. 2nd Edition, 1986.

E. Isaaks and R. Srivastava. An Introduction to Applied Geosta-tistics. Oxford University Press, New York, NY. 1989.

Independent study of the underlying theory will allow you under-stand how surface shape varies with different variograms.

The relation between variance and statistical distance is expressed as a semi-variogram, which plots semivariance along the Y axis and distance along the X axis.

A gaussian semi-variogram

γ h( )h( )

Range

Nugget

Sill

Distance (h)

γ h( )



Variogram design consists of fitting a function which describes variance versus distance for the data set being mapped. The vari-ogram is created and temporarily displayed using the Vario com-mand which displays a histogram of variance versus distance based upon the points in the current surface. The controlling parameters of the variogram curve shape are termed the nugget, range and sill. These are defined under Variogram design in the command reference chapter.

As you explore the technique, you will find that kriging can pro-duce excellent results or absolutely meaningless maps depending upon the variogram used. Effective use of kriging is absolutely dependent upon a properly defined variogram.

This version of Quicksurf supports isotropic kriging. The under-lying assumption is that the data structure is isotropic and that variograms utilizing the direction as well as distance between points would be the same.

Kriging works well on data sets representing the distribution of concentration, porosity, or permeability. Because the surface shape is highly influenced by the variogram, rather than just the data points themselves, kriging can produce smooth maps for small or sparse data sets. In cases such as mapping contaminants from leaking storage tanks, it is common to have only a dozen or so data points from monitoring wells. Kriging will generally pro-duce nicer maps than the curvature-based standard Quicksurf method in such cases.

This introduction explores the mechanics, but not the theory, of creating surfaces with kriging.

Page 396 Introduction


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Objective

Design a variogram based upon the points in the current surface and determining the nugget, range and sill. Create a grid and contours based on the kriged grid. Investigate the effects of changing variogram type and variogram parameters on the shape of the resulting surface.

Workflow

To create a grid or set of contours by the krige method, use the following steps:

• Load points into the current surface by extracting them frothe drawing or by reading them from an ASCII or QSB file

• Invoke the Configure Grid dialog and select Krige as the method and set the Neighborhood if needed.

• Design a variogram based on the points in the current surfby using Utilities -> Quicksurf utilities -> Variogram design.

• Choose variogram type and graphically design the variogrto set nugget, range and sill. Accept the variogram to exit variogram design loop.

• Contour or grid your data. The new variogram will be useto create a new grid, as long as any pre-existing grid has bcleared from surface memory.

Using kriging

Loading the data set

We will load points and generate surfaces based on the kriginmethod. First load the standard QS configuration file so we hathe same starting point:

Objective Page 397


Configuration -> Read ConfigurationRead options from file <drawingname>: QSReading options from file QS.QCF

We will read and use the Contaminant surface from the included file \QS51\DEMO5.QSB.

Surface operations

Select Read QSB and select DEMO5.QSB from the file dialog. This file is located in the \QS51 directory. This will load all of the example surfaces into surface memory. Press OK to exit the dia-log. Next use Surface zoom to align the view over the surface.


View options -> Surface viewSurface <.>: Press ? to invoke the surface pick list, select Contaminant

Show the TIN to see the distribution of the data set.

TINSurface<Contaminant>: press enter to choose ContaminantNone/Show/Draw/Redraw <Show>: Show

The raw data points are at the vertices of the triangulated irregular network. Viewing the TIN from an oblique view is a quick way to detect spurious points. The command sequence of VPOINT, Surface zoom, TIN, and Surface plan view will accomplish this.

Selecting Kriging as the grid method

Invoke the Configure Grid dialog box to select the Krige method.

Configuration -> Configure Grid

Page 398 Using kriging


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Krige section of Configure Grid dialog

Click on the Krige method button and the Krige parameter sec-tion is enabled. Pull down the Variogram pick list and select Exponential variogram type by clicking on it. Set the Neighbor-hood to six rings. The neighborhood considered is based upon the number of rings of the TIN around the grid node elevation being calculated. One ring is equivalent to using the nearest neighbors only, two rings includes the neighbor’s neighbors, eComputation time increases as the cube of the number of ringsset this number only as high as needed to produce a smooth face. Setting the number of ring to four is a good starting placfor general use. Too small a neighborhood results in surface continuities. Press OK to exit the dialog. We will use the Vario-gram design command to determine the Nugget, Range and Sill values.

Designing the variogram

A variogram must be designed or the variogram parameters mbe specified prior to creating a grid. The Variogram design com-mand does both. This command should only be run from planview.

Using kriging Page 399


Utilities -> Quicksurf utilities -> Variogram design

Surface name <Contaminant>: press enter Number of histogram intervals: <24>: press enterSelect Variogram window first corner: pick lower left corner for variogramSelect second corner: pick upper right corner for variogram

The histogram of variance versus distance is shown in this win-dow. It will disappear at the next redraw.

Typically small data sets do not have enough points to form a reli-able sill on the histo-gram. The horizontal gray line on the screen represents the mean variance of the data set and may be used as the sill.

Variogram for Contaminant surface

This graph represents the variance (y axis) versus inter-point dis-tance (x axis) of the points in the selected surface. The command continues:

Variogram type <Exp>: press enter (you set Exponential in the dialog)Point at y=nugget: <0,0>: press enter to accept a zero nuggetPoint at range, sill <previous range, previous sill>: pick range and sillSelect variogram point below sill <previous>: pick guide pointVariogram OK <N>: enter Yes to accept the variogram; No to try again

This command is designed to allow you to pick the Nugget, Range and Sill graphically or enter them numerically on the key-board. The values determined are global variables and are avail-



able to view or edit in the Krige section of the Configure Grid dialog box. When entering variogram type, you may specify Lin-ear, Exponential, Spherical, Gaussian, Piecewise or Hole.

The Nugget is the y-intercept of the variogram curve. This repre-sents the variance at a range (distance) of zero. A zero nugget means the surface must pass through each data point exactly. A non-zero nugget means that the surface may miss any point by as long the error falls within the nugget variance. You may graphi-cally pick a point on the graph and the Y value of the picked point will become the Nugget value. If you key in a value at the key-board in the Variogram design command, specify both an x and y value (such as 0,0), even though only the y value is ultimately used.

The Range and Sill may be specified by graphically picking a sin-gle point on the variogram ( x = range and y = sill). The range represents the distance beyond which the variance is constant, meaning that the z values of points beyond this distance have no influence on the elevation being estimated. The sill represents the variance at a distance equal to the range. The grey horizontal line shown on the variogram represents the mean variance of the data set and may be used as a sill estimate for small data sets which do not exhibit an obvious sill on the histogram curve.

For Gaussian or Exponential variogram types, you are prompted for an extra guide point to help determine the shape of the vario-gram curve. This point is picked between the origin and the <range, sill> point and shapes the resulting curve. The range and sill are recomputed to reflect this exact curve shape.

The variogram curve is shown as a red line on the histogram graph. If the curve is acceptable, answer Yes to the Variogram fin-ished? <N>: prompt. If not, answer No and the screen will be refreshed, the histogram redisplayed and you will loop back through the variogram design sequence. Answering Yes exits the Variogram design command.



In this example the following parameters were used:

Variogram: ExponentialNugget: 0Range: 150Sill: 300Neighborhood: 6 Rings

Using these parameters produced the following surface:

Contaminant surface using Kriging

Display the new grid

We will examine the new surface from an oblique view point. We will draw the points into the drawing so AutoCAD can have enti-ties when changing viewpoints. Use the VPOINT command to establish a viewpoint.

PointsSurface <Contaminant>: press enterNone/Show/Draw/Redraw <Show>: Draw



Command: VPOINTRotate/<View point> <0,0,1>: -2,-2,1

Create and display the new grid

GridSurface<comtaminant>: press enterNone/Show/Draw/Redraw <Show>: Show

Leave this display on your screen as we explore the effect of changing the kriging parameters.

Oblique view of kriged grid and contours

Exploring Range effects

For a given variogram type, the range has the most dramatic effect on the resulting surface. When using too short a range, each point will be surrounded by a roughly conical surface that represents a surface of revolution formed by the variogram curve. This is encountered when the inter-point distance is larger than the range. The surface value at a distance from a point which is greater than the range converges on the mean of the data set. The following figure reflects changing the range from 150 down to 15 which is much too short.



Effect of kriging with too short a range (15)

Invoke the Configure Grid dialog and change the Range to 40 leaving everything else the same. Press OK to exit the dialog. Now we will rebuild and display the grid.

Same surface with range equal 40



Rebuilding a grid with different parameters

As with any grid, changing a parameter does not alter a grid which has been previously built. To see the effect of changing a parameter, the grid must be cleared and recreated. If you just show the grid without clearing it first, you will just redisplay the old grid made with the previous settings. Building the new grid may be accomplished in several ways:

1) Use Clear Parts from the Surface operations dialog box to clear the grid.

2) If the points are drawn into the drawing, re-extract the points with Extract to surface to create a <.>surface with just points.

3) Use Cell Size or Cell Count command from the Surface options menu. These two commands clear and recalculate the grid even if the cell size/count is not altered.

For this example we will use the Cell Count option and view the new grid from an oblique angle. Rebuild the grid with the new settings:

Note: Surface Options menu selection, not Sur-face Operations

Surface Options -> Cell Count

Surface name <contaminant>: Press enter Current cell count is <26 x 19 > Horizontal cell count/Auto <default>: 50 Vertical cell count/Auto <default>: 5050 x 50 grid built

Now display the new grid:

GridSurface<comtaminant>: press enterNone/Show/Draw/Redraw <Show>: Show



Notice that with the shortened range, the surface is at the mean value of the data set between points and reflects the shape of the variogram in the vicinity of a data point. This is a misdesigned variogram and the resulting surface is not valid.

From this same oblique view try the following sets of kriging parameters. Enter each set in the Configure Grid dialog box then use Cell count and Grid / Show (as you did above) to recreate the display each new grid.

Type Nugget Range Sill Neighborhood

Different variograms for the same parame-ters affect surface shape.

Linear 0 40 300 6 RingsExponential 0 40 300 6 RingsSpherical 0 40 300 6 RingsPiecewise 0 40 300 6 Rings

Changing the range affects surface behavior between points.

Spherical 0 400 300 6 RingsSpherical 0 40 300 6 RingsSpherical 0 20 30 6 RingsSpherical 0 10 3000 6 Rings

Experimenting with variogram design will allow you to create a surface which accurately describes the phenomenon you are map-ping. A poorly designed variogram will create meaningless sur-faces.


Chapter 27: Geologic faulting

Introduction

A wide variety of faulting styles may be modeled using Quick-surf. A fault represents a discontinuity in a stratigraphic horizon where it has been broken and offset. Faulted horizons which do not have repeated section (normal faults, growth faults, etc.) may be modeled as a single continuous surface. Faulted horizons which contain repeated section (reverse faults, thrust faults, etc.) must be modeled as two surfaces, one for the hanging wall and one for the foot wall. This is because Quicksurf models single-valued surfaces, having only one z value at a given x,y location.

Contours of faulted surface

Faults are modeled using break lines. 3D break lines are created representing the intersection of the fault plane surface and the faulted horizon for both the up-thrown and down-thrown sides. For a normal fault, the resulting surface follows the stratigraphic horizon on the up-thrown side to the upper fault trace (break line), then down the fault plane surface to the lower fault trace



(break line), then follows the down-thrown stratigraphic hori-zon. The display of contours or triangulated grid on the fault plane surface itself may be optionally suppressed.

Triangulated grid of faulted surface (oblique view)

The illustration above shows the same faulted surface from the previous page in an oblique view. The TGRD has not been drawn on the fault surfaces themselves, but the surface held in memory is continuous across the faults. If a drill hole actually intersected the fault surface, this point may be used a a defining point for the surface. The edges where the horizon intersects the fault are break lines. Creating 3D polylines for break lines is the key to effective fault modeling.

Much of this manual speaks in civil engineering terms about topographic modeling with break lines. Once the geologist real-izes that a faulted surface model is no different than an engineer-ing topographic model containing break lines, it becomes apparent that the tools of drape, flatten, vertical align and inter-sect slope may be used in a similar fashion for fault break line construction and editing. Examining Chapter 22 (page 363) on wall construction will reveal that a retaining wall is analogous to a normal fault at least in terms of how it is created.

Page 408 Introduction


Constructing fault break lines

The basic work flow when constructing break lines for faults con-sists of drawing the plan view orientation of the fault traces and converting them into 3D polylines using Drape or Extrapolate to get a starting point. The resulting 3D polylines will have the cor-rect horizontal alignment and a rough first pass on the vertical alignment. The vertical alignment of both the upper and lower fault traces are then plotted on the same 2D profile using Flatten. If you flatten the upper fault trace first and supply a low base point elevation, the resulting graph will be tall enough to accomo-date the second flattened profile.

New vertical alignments for both fault traces are drawn (or the originals edited) on the 2D profile. This allows both absolute structural position for both fault traces and fault throw to be con-trolled simultaneously. Each of the adjusted fault profiles are re-applied to the 3D fault traces in the model using Vertical Align. Now the 3D polylines representing the fault traces are at their correct position in 3D space, ready to be extracted as break lines.

Many times you may already have the 3D position of the fault trace from other sources such as seismic workstation output or pre-existing mapping. These may be loaded using Load ASCII Breaks or by drawing the 3D polyline by snapping to the points where pre-mapped contours intersect the fault. In the latter case, the x,y location of the intersection of the contour line and the fault is used in combination with the z elevation of the contour line itself as 3D polyline vertices.

A step by step summary of the workflow when creating a normal fault is presented on the next page.

Constructing fault break lines Page 409


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Workflow

• Load the existing surface control points

• Draw 2D polylines in map view representing the fault traceRemember a normal fault has two break lines: one where upthrown block is cut by the fault and one where the downthrown block is cut by the fault. As the angle of the fault surface approaches vertical, these break lines may bvery close to each other in map view.

• Turn the 2D polylines into 3D polylines using Drape or Extrapolate for a rough 3D positioning. Alternatively you may actually draw the 3D polyline if you have independenposition information about the fault location.

• Flatten both 3D polyline fault traces onto the same 2D profby running Flatten twice and using the same origin and baspoint when flattening the second fault trace.

• Adjust both fault traces on the 2D profile to reflect both structural position and throw. You may either edit the exising 2D polylines or drawn new ones.

• Use Vertical align to apply the new vertical alignment of the adjusted fault profiles back to the 3D polylines in the mode

• Use Extract to surface to extract build a new surface with justhe control points (not the break lines).

• Use Extract breaks to extract the break lines representing thfault traces.

• Set to contour on the TGRD in the Configure Contour dialog.

• Show the contours using Contour / show.

• View the TGRD from an oblique view.

• Adjust the fault break lines if necessary and recreate the sface starting at the Extract to surface step above.

Page 410 Workflow


Surface with no faulting

The figure above is contoured on the data points only (no break lines) using the standard (continuous curvature) method. Many curvature artifacts may be seen as anomalous highs and lows. The location of the first pass break lines are shown. These break lines have been flattened on the same 2D profile graph below. New vertical profiles have been drawn for both the upper and lower fault traces.

Flattened profile with adjusted faults

Workflow Page 411


Preliminary fault break lines

The figure above shows the position in 3D of the original fault break lines and also shows the original surface created just with the control points (without break lines). The figure below shows the same view with the adjusted break lines having been incorpo-rated into the surface. The adjusted break lines from the 2D graph were re-applied to the actual break lines using the Vertical align command.

Final faulted surface

Page 412 Workflow


Contour map of final surface

The above figure shows the resulting contours (based on the TGRD) when the faults are incorporated as break lines. The con-tour lines appear to merge in the fault due to the 10 foot contour interval and approximately 160 of throw on the fault.

If you do not want to have the fault plane contoured, use a nested boundary polygon covering the plan view area of the exposed fault plane. This closed polyline may be easily created by snap-ping a line to join the ends of the upper and lower fault break lines, then using the Create Boundary Polyline command from the utilities menu.

Workflow Page 413


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Using Drape and Extrapolate

Building the break lines representing the fault traces is the most difficult part of fault modeling. While Flatten and Vertical align allow for precise fine-tuning of fault geometry, creating the first pass rough 3D polyline representing the fault is a challenge. Three approaches are commonly used.

• Draw the 3D polyline manually

• Drape a 2D polyline onto the (unfaulted) surface

• Create a 3D polyline from a 2D polyline by Extrapolating just the wells in the fault block to create the fault trace

Each of these will be discussed separately.

Manual break line construction

The first pass for a fault does not need to be overly complex. Many times you can simply draw a 3D polyline representing thfault trace using a dozen points or less. The detailed geometrthe fault may be added to the flattened 2D profile and re-appliusing Vertical align. Careful use of filters (such as .xy) and objesnaps allow you to quickly build a 3D polyline representing thefirst pass of a fault trace.

Drawing the fault trace can incorporate outside data such as smic or pre-mapped fault positions.

Draping break lines

The Drape command is a powerful tool for creating 3D polylinesWith subtle normal faults, you may create a surface from the existing well control without using any break lines and drape a2D polyline (representing the map view of the fault trace) ontothe planar TIN to get a 3D polyline starting point. In such casbe sure to drape onto the planar TIN, because typically faultedareas have locally steep slopes and using curvature-based sufaces in ill-advised until the break lines have been determined

Page 414 Using Drape and Extrapolate


In many cases it is easy to create a temporary surface for draping. This is accomplished by using only the control points within the fault block and adding additional points on the "other side" of the fault to extend the fault block surface through the fault plane. Creating a smooth surface under the 2D fault trace then allows you to drape the 2D fault polyline and create an excellent smooth 3D polyline for the fault break line. The same sequence is repeated for the adjacent fault block.

When draping a fault trace polyline, remember that the surface must have at least a TIN and be defined under the polyline. If your fault trace polyline extends off the edge of the defined sur-face, those vertices off of the surface will be assigned the Unde-fined grid value elevation from the Configure Grid dialog box. To avoid unnecessarily dense vertices on draped polylines, you may manually set Drape step size in the Configure Drape dialog to a discrete value.

Extrapolating break lines

If sufficient control exists within a fault block to extrapolate gra-dients, the Extrapolate command may be used to create a 3D polyline from a 2D or 3D polyline which does not necessarily overlie the surface. Extrapolate functions like Drape in the sense that it adds new vertices, and only adjusts the z values of the ver-tices, leaving the horizontal alignment the same. The spacing between added vertices is controlled by the Drape Step setting in the Configure Drape dialog box.

Extrapolation should never be relied on without careful inspec-tion of the result. The Extrapolate command uses the gradients from the local neighbors to determine elevation values at a point off of the surface. The result is highly variable depending on the distribution of points within the surface and the horizontal dis-tance between the surface edge and the polyline being adjusted. Because different algorithms are used, Drape and Extrapolate may produce different results for entities which overlie the sur-face.

Using Drape and Extrapolate Page 415


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To use Extrapolate, follow this general workflow.

• Create and TIN a surface containing only the points in thefault block being considered. Insure that there are sufficiepoints from which to extrapolate gradients. Nearly linearlydistributed point sets (in map view) will not work.

• Draw the 2D polyline representing the fault trace for the edof this fault block only.

• Use Extrapolate to convert the 2D polyline into a 3D polyline.

• Examine the resulting 3D polyline in from a 3D view.

• Extract this 3D polyline as a breakline (adding it to the TINyou created above), then create and display the TGRD forjust this fault block.

• Each fault block has its bounding fault trace created sepa-rately in this way.

If you only have a handful of points in a fault block, you may want to utilize Build surface command to build an inclined planeupon which to drape your fault trace polyline.

Step by step examples of working with break lines are shown the earlier application examples, such as pad and ditch constrtion. Constructing faulted surfaces is identical once the fault break lines are built.

Page 416 Using Drape and Extrapolate

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Chapter 28: Architectural uses

Quicksurf has obvious application in site design and lighting studies, but several of the surface modeling tools can save consid-erable time when applied to polyface mesh creation. Complex wall polyface meshes may be quickly built using the TIN and TGRD commands together with break lines and boundaries. Site design, slope analysis and surface coloration by light, shadow or visibility are covered elsewhere in this manual. The objective of this short chapter is to raise the architect’s awareness of the aity to build polyface meshes covering surfaces with curved opings.

Creating polyface meshes using breaks and boundaries

By selecting wall openings and perimeter polylines as both breaks and boundaries, you may use the TIN command to crepolyface meshes for the wall. All of the defining polylines maybe 2D polylines at the same elevation. If the wall is modeled vtically, which is the normal case, you will need to establish a UCin the plane of the wall and both extract the entities and TIN thwall while in this UCS. You must also set the COORSYS variable as described in the User Coordinate Systems chapter on page

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Quicksurf

Chapter 29: Configuration files

Configuration files are ASCII text files which contain the current configuration of all global Quicksurf variables. Configuation files may be read and written using the Read Configuration and Save Configuration menu commands. The List configuration command displays the configuration file to the AutoCAD text screen one page at a time.

Each Quicksurf variable has an associated keyword which is listed on the left side of the configuration file. Any variable may be set from the keyboard with the QSOPT command. For exam-ple, the contour interval may be set to 25 with the following com-mand sequence.

Command: QSOPTKeyword: IntervalContour Interval/Auto <Auto>: 25

Any Quicksurf variable may be similarly set from the keyboard.

Configuration files with the same name as the drawing are auto-matically read upon opening the drawing. If such a configuration file is not found, the QS.QCF configuration file is read. If no con-figuration file is found, the internal defaults are used. A configu-ration file may be created with the current settings at any time by selecting Save Configuration from the menu.

A typical configuration file is listed on the next few pages.

Page 419


; File: \qs51\qs.qcf; Quicksurf 5.xx Options;;Keyword = Value(s) ; Description;---------------------------------------------------------

curname = ; Current surface namesurfsort = Yes ; Use sort in surface listwindow = Max ; Current working windowacute = 0.0000 ; Triangulation constraintcellsize = Auto ; Cell Sizecellcnt = Auto ; Grid Countcellfac = 4.0000 ; Cell count factorcellmin = 500 ; Minimum Grid Cellscellmax = 50000 ; Maximum Grid Cellsusegreg = No ; Use grid registrationpingrid = 0.00,0.00 ; Grid registration pointmeshbase = 0.0000 ; Base Elevation for Meshinterval = Auto ; Contour Intervallevels = 20 ; Contour Levelselevfile = ; Elevation list file namerough = No ; Use frame points onlycolor = Yes ; Color Contourscolcont = Cycle ; Color contour methodc1split = 5 ; Low Contour Color Splitc2split = 15 ; High Contour Color Splitcesplit = 0.0000 ; Contour color elevation splitc1intvl = 5 ; Base Contour Colorc2intvl = 15 ; Highlighted Contour Colorchintvl = 5.0000 ; Interval for highlighted contourscolcyc = 1 ; Starting Cycle Colorncolcyc = 20 ; Number Cycle Colorscmapfile = C:\QS51\STDQS ; Color mapping file namehowcolor = Elevation ; Paint methodslmeth = ; Slope methodstartcol = 1 ; Starting Surface Colorncolors = 20 ; Number of Colorscolintvl = 1.0000 ; Contour color cycle interval

Page 420


blnkcolor = 251 ; Blank surface colorusecrange = No ; Use the color range for paintcmaxv = 10000000.000 ; Maximum value for paintcminv = -1e+007 ; Minimum value for paintviewpnt = 0.00,0.00,0.00 ; Surface paint view pointtargetpnt = 1.00,1.00,0.00 ; Surface paint target pointuselegend = No ; Surface paint legendshowcolor = XOR ; Show Color Methodverbose = 1 ; Verbose Modegmethod = 1 ; Grid Methoddorder = 2 ; Derivative Orderborder = 2 ; Blend Orderweight = 2 ; Weighting powerhonor = No ; Honor local extremaneighmethod = 1 ; Neighbor selection methodcoorsys = Yes ; World coordinatesrings = 2 ; Number of Ringsttype = 2 ; Trend Typetorder = 4,4 ; Trend Ordercmethod = Grid ; Contour Methodusecntrg = No ; Use contour rangemincont = -1 ; Minimum contour valuemaxcont = 1.0000 ; Maximum contour valuebmethod = 1 ; Boundary Methodmaxsop = Yes ; Maximize SOP dataptonbrk = Yes ; Use points on breaksdrbase = TIN ; Drape Basedrorder = 1 ; Drape Orderdrstep = Auto ; Drape Step Sizestackfac = 1e-014 ; Stacking constraintbrkcrverr = 0.0000 ; Break line curve errorbrkacc = 0.0010 ; Break accuracy tolerancecurvefac = 0.0005 ; Curve error factorleanleft = No ; Lean leftavoid = No ; Avoid Redrawingshowhi = No ; Show Highlightedusedstep = No ; Use densifying stepdenstep = Auto ; Densify Step Size

Page 421


usefilter = No ; Use extract filteruselayer = No ; Use layer filterfiltlayer = ; Data layer nameuserange = No ; Use Z range filterminelev = -90000 ; Minimum Z valuemaxelev = 90000.0000 ; Maximum Z valuenpmax = 2000000 ; Max number of extracted pointsfname = <none> ; Loading points file namecolpos = 1,2,3 ; Column Positions for reading datascalefac = 1.00,1.00,1.00 ; Scale Factorbldtype = 0 ; Build surface typeextents = -1000000000000.000,-1000000000000.000 x 1000000000000.000,1000000000000.000postoff = 1.00,1.00,0.00 ; Posting offsetcamheight = 10.0000 ; Camera Heightcamlens = 30.0000 ; Camera Lensslpunit = 0 ; Units for slopesvolconv = 1.0000 ; Conversion for Volumesvolunit = ; Volume unit stringarconv = 1.0000 ; Conversion for Areasarunit = ; Area unit stringboundtol = No ; Boundary tolerance promptintstep = Auto ; Intersect Step Sizeintslpupr = 1.0000 ; Right Initial Slope Upendslpupr = 1.0000 ; Right Ending Slope Upintslpdnr = 1.0000 ; Right Initial Slope Downendslpdnr = 1.0000 ; Right Ending Slope Downintslpupl = 1.0000 ; Left Initial Slope Upendslpupl = 1.0000 ; Left Ending Slope Upintslpdnl = 1.0000 ; Left Initial Slope Downendslpdnl = 1.0000 ; Left Ending Slope Downgenseed = Auto ; Seed number for terrain generatorvariotype = 0 ; Variogram typehistintvl = 24 ; Histogram intervalsnugget = 0.0000 ; Nuggetrange = 1.0000 ; Variogram rangesill = 1.0000 ; Variogram sill

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Chapter 30: Keyboard equivalents

Commands which have keyboard equivalents are listed below. The menu automatically loads commands if they are not yet loaded, so if you receive an UNKNOWN COMMAND error when attempting a keyboard command, select the command from the menu once to load the command. Subsequent keyboard access will work normally.

Data input

From the drawing..

QSX Extract to surfaceQSBX Extract breaksQSMX Merge extract

From ASCII...

QSL Load ASCII single surfaceQSML Load ASCII multi-surfaceQSBL Load ACSII breaksRBOUND Load ASCII boundaryQSLDEM Load DEM data

Data Export

To ASCII..

QSXPORT Export ASCII from memoryDWG2TXT Extract ASCII from drawingWBOUND Write ASCII boundary

To 3D Studio..

QS3DS Export to 3DS from memory

Data input Page 423


Surface commands

Boundaries

BOUND Boundary

Create / Display

PNTS PointsBREAKS BreaksTGRD Triangulated gridTIN TINGRD GridCONT ContourIDWG Inverse distance by gradientIDWO Inverse distance by observation

Modify

CSURF Current surfaceDSOP Surface managementSOP Surface operations (no dialogs)EXTEDGE Extend edgeTINEDGE TIN edge

Viewing

SVIEW Surface viewSETCAM Configure cameraSPLAN Surface plan viewSZOOM Surface zoom

Annotation

POST Post from memorySETPOST Configure postDPOST Post entitiesSMOO Smooth contoursINDEX Index contoursLABEL Label contoursMLABEL Auto-label contoursTICK Hachure contours



Color control

PAINT Surface colorsPFILL Screen fillDCMAP Remap ColorsLCMAP Load Color MapRCMAP Reset Color Maps

Volumes

AVOL Area volumeBVOL Boundary volumeSVOL Surface volumeVOLUME Volume by entity

Design Tools

QSBLD Build surfacesTGEN Generate terrainAPSEC Apply sectionDRAPE DrapeFLATTEN FlattenISLOPE Intersect slopeSETSLOPE Configure intersect slopeISURF Intersect surfaceSECT Cross-sectionSECT_SETUP Cross-section setupREGION Surface regionVALIGN Vertical align

Utilities

Elevations

TRACKZ TrackzDELEV Display Z of entityCELEV Change Z of entitySETZ Set ZSELZ Select by ZSCALEZ Scale Z of entities



Quicksurf

QSOPT Set option by keywordQS Command listQSVER VersionFLOW Draw 3D flowlinesGPED Grid pedestalMAVG Moving averageVARIO VariogramVOR Voronoi diagram

Polylines

3DOFFSET 3D polyline offsetSWAPPOLY Swap endsCBND Create boundaryMK2DPOLY Make 2D poly3PEDIT 3D polyline mergeDENSIFY Densify verticesPOLYDASH Dash a polylineXSEIS Export comma-delimited 3D poly

Polyfaces

WELD Weld 3D facesLINER Normal offset 3D mesh

General

TD Toggle dialogsESEL Erase selectedSETL Set layerMAP Rubber sheetingWRAP Wrap to sphereUNWRAP Spherical to rectangularSCALESYM Scale symbolsNUMBER Sequentially numberRARIFY Rarify points

Page 426 Utilities


Surface operations

Surface management

SOP CLearSOP DELeteSOP COPySOP MOVeSOP RENameSOP LOadSOP SAveSOP DESCriptionSOP LAYerSOP LIst

Surface modification

SOP CS Cell sizeSOP CC Cell countSOP CF Cell factorSOP WINdowSOP SETSOP MErgeSOP SPliceSOP Zrot Z rotationSOP XTrans Translate XSOP YTrans Translate YSOP XSCale Scale XSOP YSCale Scale Y

File operations

SOP READ Read QSBSOP WRITE Write QSB

Surface operations Page 427


Mathematical operations

SOP + Add (+)SOP - Subtract (-)SOP * Multiply (*)SOP / Divide (/)SOP % Remainder (%)SOP MAX MinSOP MIN MaxSOP ABslope Absolute valueSOP SQrt Square rootSOP EXP ExponentialSOP POWER10 Power10SOP LN LnSOP LOG LogSOP SIN SineSOP COS CosineSOP ATan ArctangentSOP FLoor FloorSOP REC ReciprocalSOP ASL Absolute slope in decimal percentSOP DSL Absolute slope in degreesSOP XSLope Slope in XSOP YSLope Slope in YSOP RES ResidualSOP TRend Trend

Page 428 Surface operations

Chapter 31: Trouble shooting

Commonly encountered problems and their remedies are listed below.

Program doesn’t run

Unknown command error

If you receive an Unknown command error, either the command is not loaded or the directory with the Quicksurf programs is not in the ACAD search path. At the AutoCAD Command: prompt type QS followed by a return. This should echo the Quicksurf command list to the text screen. If you receive an Unknown com-mand error, then the main Quicksurf parent program is not loaded. Quicksurf is loaded by invoking the Quicksurf menu. Load the Quicksurf menu using the AutoCAD MENU command, see page 43. If the problem persists, you have an incorrectly specified AutoCAD path statement, see page 12.

Some LISP routines are loaded by the menu as they are selected. If you are typing the command at the keyboard and receive an Unknown command error, select the command from the menu the first time to load it. Subsequent use from the keyboard will work normally. This is the case with all utility commands.

Menu misbehavior

If menus or dialog boxes do not function properly, you have not loaded all of the component parts to Quicksurf or you have installed the Windows version of Quicksurf on the DOS version of AutoCAD or vice versa. You also could have two different versions of Quicksurf on the same machine.

Page 429


, ro-

In such cases, the fastest remedy is to delete all Quicksurf files and reinstall the proper version of the program. Use a file-find program to locate all copies of any of the following files and delete them from your disk.

qs.exp (DOS executable)qs.exe (Windows executable)qs.dclqs.lspqs.hdxqs.hlpqs.qcfqs51.mnuqs51.mnlqs51.mnxqsedit.lspqsopts.lspqsopts.dclbonus.lspmsgfile.qlbsikey.exetxt.exp

After deleting any copies of these files, re-install the proper ver-sion of Quicksurf for your version of AutoCAD see “Installation” on page 10.

Data import problems

Occasionally files imported from other platforms will contain non-printing characters or non-standard line terminations. A quick fix is to load the data file into a word processing programthen save the file again as an ASCII text file (not in the word pcessors format!). Most of these programs automatically strip offending characters.

Page 430


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e.

our

Extract problems

If you are using one of the Extract commands and are not getting any entities selected, you may be using one of the Extract filters improperly. Invoke the Configure Extract dialog and correct the problem by de-selecting all filters.

If you are extracting entities and the display of them (Points, TIN, etc.) is in a different place than expected, or you do not see them at all, you may be displaying in a UCS. Change to world coordi-nates or if you need to be in the UCS, see “Extract commands and User Coordinate Systems” on page 327.

Display problems

If Quicksurf commands do not display properly, or you do not sany display at all, one of the following may be the cause.

SOP Window

If you have a window set which does not coincide with your view, the grid may not exist in your view area. Use Surface Options -> Window to set the window to Max.

User Coordinate System set

If you have a UCS set, Quicksurf will display relative to that UCS. Quicksurf extracts in World coordinates and displays inUser coordinates unless overridden by the COORSYS variablChange to World coordinates and try again.

Displaying in background color

You may be showing or drawing in the background color. Thiscan be due to Set SHOW color being set to the background coloror using a misdesigned color (.CLS) file. Set surface and contcolors to None and try again.

Page 431


Elevations out of range

If contours are not showing, you may have a Z range set within Configure Contour that does not overlap the data being contoured.

Single pixel display

If your view is zoomed back from your surface by a large amount, the entire surface may be represented by one pixel. Use View options -> Surface Zoom to register the view with the sur-face.

Speed problems

Step size or cell size

If the program is running a very long time on a problem, you may have set a very small grid cell size, drape step size, break toler-ance or break curve error. Quicksurf will do as instructed if given a very small grid cell size, step size, tight tolerance, but this may take a long time and result in very large files. Set the size or tol-erance manually in the appropriate configuration dialog.

Undo list

AutoCAD maintains an Undo list which records every action from the beginning of the drawing session. This file can grow to be many times larger than the drawing if you are adding and eras-ing large entities such as polyface meshes. When this file grows to a certain size, you machine will start swapping and slow down considerably. Eventually the swap file can fill your entire hard disk and AutoCAD will abort with an AFPAGER error.

You may disable the undo list by typing

Command: UNDOAuto/Back/Control/End/Group/Mark/<Number>: ControlAll/None/One<All>: None

This will disable UNDO and henceforth AutoCAD will not create a list, but it will not reclaim the room taken by any pre-existing undo list file until you exit AutoCAD entirely. If you wish to

Page 432


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leave undo enabled and are drawing and erasing large entities, periodically (every few hours) save your drawing and surfaces, then exit and reload AutoCAD.

Grid problems

If you receive a grid undefined error, you have the probably used surface operation Window improperly or set a cell size larger than the X, Y range of your data. If the current window and your data set do not overlap, when viewed from plan view, a Grid unde-

fined error may result. Setting the window while in a UCS will cause further confusion as the window will be set using UCS coordinates and your data will more than likely be in world coor-dinates (WCS).

AF pager error

If you receive this error, you ran out of space on your hard disk drive. AutoCAD’s swap file grew larger than your available disspace. See the Undo list entry above.

Annotation Problems

Label, Post and Post Entities all rely on certain AutoCAD settinsuch as text style (including font, text height, width factor), objesnap modes, and pickbox size. Problems may result with versmall fixed text heights, with pickbox size set to zero, or with object snaps set to anything other than None.

If you encounter problems, use undo to undo the error, then veOSNAP is set to None, PICKBOX is set to greater than zero, ause the Style command to set a variable text height (specify 0and a width factor of 1.0.

Page 433

Lengthy Auto Densification

Auto densification re-triangulates a surface with break lines until no triangle of the TIN crosses a break line. Normally this is quite fast, converging in two or three iterations. In certain rare geome-tries, this process may iterate many times. If left alone, it will complete the auto densification, but the time required may be unacceptably long on large models. Auto densification is con-trolled by two setting: Break tolerance and Curve break error, both found in the Configure Breaks dialog box. Increasing either of these values will cause Auto densification to converge sooner.

For quick-look approximations of the surface, you may avoid auto densification altogether by selecting Densify during extract and an appropriate Densify step size in the Configure Extract dia-log box. Then use Extract to surface to extract both points and break lines together, then immediately TIN the result. In this case, bypassing Extract breaks skips auto densification. The resulting TIN may have triangles which cross break lines, but they will be smaller than the Densify step size used. If you use this trick, remember to deselect Densify during extract in the Con-figure Extract dialog when through.

Page 434 Quicksurf

Index

3D polylinesVertical adjustment 152

3D Studio 323Creating surface patches 164Direct surface export to .3DS file 323Exporting mesh objects 323Materials segregation 165Morphing Quicksurf surfaces 325Partitioning large surfaces 325Subdividing surfaces for different materials 324

3DS files 323

A

Absolute value of a surface 262ACAD path variable 12ACADR12.BAT 12Adaptive densification 274Addition (+) 260Annotation 57, 102

Common posting problems 107Configuring Post from memory 221Contour labels 112Contour tick marks 113Posting drawing entities 105Text properties 103

Apply sectionCommand 155Cross-section template example 373Example 367Slope configuration 225Slope control lines 228Vertical transition 230With no slope intersections 228

Area calculationUnits 219

Area volume command 139ASCII files 65, 68

Assigning surface names 70Boundaries 75, 80Break lines 73Configuration 223Delimited 69Delimiter and quote characters 71Exporting 79

Exporting numbered 3D polylines 183Fixed length 72Scale factors 224

Aspect surface analysis 120AUTOEXEC.BAT 12

B

BBS 19Blend order 202Block models 175Boundaries 54, 99

ASCII files 75, 80Boundaries and Drape 144, 281Boundaries and surface displays 271Boundary smart commands 269Boundary tolerance prompt 218Configuring 218Create polyline utility 182Creating and deleting 100Establishing boundaries 270Example 340, 349Nested boundaries 271

Break lines 63, 273Adaptive densification 274ASCII files 73Configuring break extract 213Constructing 149, 155Creating 273Curve error 214Definition 30Example 277, 341, 352, 360, 379Geologic faults 407, 414Intersecting break lines 33, 276Resolving break lines 275Tolerance 213Using 276

Break lines and Drape 213Breaks

Definition 25Breaks command 84Building pad example 335

Index Page 435

Index

C

Cell count 199, 251Example 405

Cell factor 252Cell size 198, 251Close all option on contours 92CLS files 128Color control 114Colors

ASCII color map files 128Contour colors 130, 210Remapping 127Saving and loading color maps 128Screen fill 131SHOW Color 129Slope analysis 385Surface color intervals 125Surface color sequence 122Surface colors 114XOR show color 129

Command list display command 172Command reference 61Commands

3D flowlines (FLOW) 1733D polyline offset (3DOFFSET) 182Apply section (APSEC) 155Area volume (AVOL) 139ASCII to QSB (ASC2QSB) 73Auto-label contours (MLABEL) 112Boundary volume (BVOL) 140Breaks (BREAKS) 84Build surface (QSBLD) 161Change Z of entity (CELEV) 168Command list (QS) 172Configure Camera (SETCAM) 98Configure post (SETPOST) 103Configure slopes (SETSLOPE) 150Contour (CONT) 91Contour colors 130Contour Interval 93Create boundary (CBND) 182Cross-section (SECT) 147Current surface CSURF) 94Densify vertices (DENSIFY) 183Display Z of entity (DELEV) 168

Drape 143Erase selected (ESEL) 185Export 3D polyline (XSEIS) 183Export ASCII from memory (QSEXPORT) 79Export to 3DS from memory (QS3DS) 81Extract ASCII from drawing (DWG2TXT) 80Extract breaks (QSBX) 63Extract to surface (QSX) 62Extrapolate (EXTSURF) 165Factory Configuration 197Flatten 145Generate terrain (TGEN) 171Grid (GRD) 87Grid pedestal (GPED) 175Hachure contours (TICK) 113Index Contours (INDEX) 110Intersect slope (ISLOPE) 149Intersect surface (ISURF) 164List Configuration 196Make 2D poly (MK2DPOLY) 183Merge 3D polyline (3PEDIT) 183Merge extract (QSMX) 63Moving average (MAVG) 175Offset 3D mesh (LINER) 184Points (PNTS) 83Post entities (DPOST) 105Post from memory (POST) 102Quicksurf Version (QSVER) 172Rarefy points 192Read ASCII Boundaries (RBOUND) 75Read ASCII Breaks (QSBL) 73Read ASCII Points (QSL) 65Read ASCII Table (QSML) 68Read Configuration 197Read DEM file (QSLDEM) 76Remap colors (DCMAP) 127Rubber sheeting (MAP) 185Save Configuration 197Scale symbols (SCALESYM) 190Scale Z of entities (SCALEZ) 169Screen fill (PFILL) 131Select by Z (SELZ) 170Set Boundary (BOUND) 99Set layer (SETL) 185Set SHOW color 129Set Z (SETZ) 169

Page 436 Index

Index

Smooth Contours (SMOO) 108Surface area (SAREA) 184Surface colors (PAINT) 114Surface operations (DSOP) 93Surface operations without dialogs (SOP) 94Surface plan view (SPLAN) 96Surface region (REGION) 164Surface view (SVIEW) 97Surface volume (SVOL) 138Surface zoom (SZOOM) 96Swap ends (SWAPPOLY) 182Tilt 187TIN 84TIN edge (TINEDGE) 172TrackZ 167Triangulated grid (TGRD) 86Untilt 188Unwrap to plane (UNWRAP) 189Variogram design (VARIO) 177Version (QSVER) 197Vertical align (VALIGN) 152Volume by entity (VOLUME) 141Voronoi diagram (VOR) 181Weld 3D faces (WELD) 184Wrap to sphere (WRAP) 188Write ASCII Boundaries (WBOUND) 80

Cone construction 162Configuration files

About 195File contents 419Listing 196Reading 197Saving 197

Configuration, resetting defaults 197Configure ASCII Load 67, 223Configure Boundary 218Configure Breaks 213Configure Camera 98, 220Configure Colors 115, 122Configure Contour 207Configure Contour messages 210Configure Drape 211Configure Extract 214

Densify during extract 215Configure Grid 198Configure Post 103, 221

Configure Section 230Configure Slopes 150, 225Configure Surface Operations 237Configure Units 219Constructing fault break lines 411Construction surfaces 161

Example 347Contaminant modeling 391Continuous curvature grid method 201Contour colors

Cycle option 130Interval option 130Split option 131

Contour command 91Contour interval

Setting 93, 208Contours 26

And hatch patterns 390Basis 207Color control 130Colors 210Configuration 207Constraining to a Z range 208Contouring specific elevations only 209Correcting short-cutting contours 331Definition 34Edge effects 334Hachure marks 113Indexing 110Labeling 112Logarithmic contours 209Of slopes 385Smoothing 108Working with extracted contours 329

Control line for Apply Section 160, 370Converting 2D maps to 3D maps 282COORSYS variable 327Copying surfaces 243Create boundary polyline 382Cross-section command 147Cross-section templates in Apply Section 159Cross-sections

Background grid 234Configuration 230Horizontal scale 232Labeling 234

Index Page 437

Index

Layer control 236Scaling 230Setting vertical range 233Vertical scale 233X origin offset 236

Current surface 94, 241Curvature 27Curvature and Drape 279Curvature control 201Curve error for break lines 214Customer support 19

D

Data export 79Data input 61Default settings 197Deleting surfaces 243DEM projection 78Demo mode 44Densify during extract 215Densify step size 215Derivatives concepts 27Derivatives setting 201Design Tools 143Detailed surface information 243Digital elevation models (DEM) 76Directory for Quicksurf files 11, 15Display problems 253, 269Displaying a surface 46Ditch construction example 355Division (/) 260Dongles 17Drainage 173Drape 51, 279

And break lines 213And curvature 279Concepts 279Configuration 211Constructing break lines 282Construction surfaces 161Converting 2D maps to 3D maps 282Drape and Boundaries 281Drape and boundaries 144Drape basis 279

Drape order 212Drape step 212Draping fault break lines 414Draping hatch patterns 285Draping off the edge of a surface 280Draping to the grid 212Draping to the TGRD 212Draping to the TIN with Derivatives 212Example 346, 359Results of draping different entities 143Step size 280Surface for draping 211Undefined areas 200Using 281

Drape command 143Draw versus Show 23, 82Drawing legend for colors 121

E

Edit points 288Editing contour polylines 291Editing surfaces 287Elevation determination using TrackZ 167Elevation list file 209Elevation utilities 167Entity filter dialog box 216Entity filters during extract 215Erase selected command 185Examples

Changing grid cell count 405Ditch construction 355Extracted contours tutorial 330Flatten 371Geologic faults 409Kriging 397Pad construction 335Pond construction 343Road construction 367Variogram design 399Vertical align 371

Exponential of a surface 263Exponential variogram type 179Exporting data 79Extract

Page 438 Index

Index

And User Coordinate Systems 217Extracting smoothed polylines 217Filter by entity type 215Filter by layer 216Filter by Z value 217Maximum number of points 217

Extract Breaks 273Example 360Repeated triangulation 275

Extract commands and user coordinate systems 327Extract configuration 214Extracting contour polylines 329Extracting drawing entities 62, 64Extrapolate and faults 414Extrapolate command 165Extrapolating break lines for faults 415

F

Faulting 165Faults 407

Building fault break lines 414Constructing fault break lines 409Using Drape and Extrapolate 414Using Flatten and Vertical align 411Vertical 363

Fax number 19Filter by entity

Example 340, 360, 378Filter by Entity during extract 215Filter by Layer during extract 216Filter by Z 217Flatten

Example 371Using with faults 411

Flatten command 145Flowlines 173

G

Gaussian variogram 179General utilities 185GENSEED variable 171Geologic faults 407Gradient flowlines 173

Graph properties for 2D cross-sections 232GRD command 87Grid 24, 26

And boundaries 218As polyface meshes 90Blend Order 202Cell count 251Cell Factor 199Cell factor 252Cell size 251Configuration 198Contouring on the grid 207Definition 28Draping upon 212Drawing a pedestal 175Grid Methods 201Grid Registration 200Honor local Extrema 203Krige method 205Number of cells 199Registered Grids 259Setting cell count 199Setting cell size 198Setting Derivatives 201Trend method 203Undefined Grid Value 200Volumes 134Volumes under a grid 306Weighting factor 202

Grid cell count 199Grid cell size 198

Changing 49Grid command 87Grid methods

Continuous Curvature (Standard method) 35Kriging 36Standard method 201Trend surfaces 35

Grid undefined error 88

H

Hardware keys 17Hardware requirements 9Hatch pattern draped on a surface 285

Index Page 439

Index

Hatch patterns and contourExample 390

Hierarchy of surface parts 257Honor local extrema 203Horizontal arc to vertical curve using drape 284Horizontal scale for cross-sections 232Howsmooth 109Hydrocarbon pore volumes 140

I

Index contours 58Indexing contours 110Installation 10

For DOS AutoCAD R12 10For Windows AutoCAD R12 14From CD ROM 10

Intersect slopeExample 338, 348Slope configuration 225Slope control lines 228Step size 228

Intersect slope commands 149Intersecting slope control 229Introduction 9Invisibility 86

Invisible show color 129TIN 85

Iso-slope contours 386

K

Keyword options 171Kriging 36, 177, 205

Contaminant data 392Example 397Introduction 395Range effects 403References 395References for further reading 181Small data sets 400Variogram design 177

L

Labeling contours 58, 112Layers and surfaces 245, 249Lighting surface analysis 116Limitations of surface size 22Linear variogram 179Logarithm base 10 of a surface 263Logarithm of a surface 263Logarithmic contours 209

M

Mathematical surface operations 246, 256Mathematical surface operators 260Maximize surface operations 237, 258Maximum of two surfaces 262Menus 37Merging data 63Merging data sets 254Mesh grids 90Minimum of two surfaces 261Moving average of a surface 175Multiplication (*) 260

N

Natural Logarithm 263Negative volume 303Neighborhood for kriging 205Network considerations 18Non-printing characters in data files 66Normal faults 407Nugget 180, 401

O

Offset example 358Overshoot control 203

P

Partitioning surfaces 164Parts of a Surface 24Perspective view 97, 220

Page 440 Index

Index

Camera lens 99Example 361, 379Height above surface 98

Phantom points 288Phone numbers 19Plane construction 162Point to Point surface operations 256Points 24

Definition 25Posting points from memory 102Posting Z values of drawn points 105

Points command 83Polyface meshes

Creating from 3D faces 184Grids 90Normal offset 184Surface area 184

Polyface utilities 184Polylines

Densification 215Extracting smoothed polylines 217Make 2D utility 183Merging 3D polylines 183Offsetting in 3D 182Reversing vertex order 182Vertex densification utility 183

Polynomial trend surfaces 203Pond construction example 343Positive volume 303Posting drawing entities 105Posting Z values 102Posting Z values from memory 102

Configuration 221Posting Z values of points 59Profiles 52, 145, 147, 230

Example 370Projecting slope 149

Q

QCF files 195QSB files

Creating from ASCII files 69Reading 242Writing 242

QSOPT command 171, 196, 419Quicksurf utilities 171Quicksurf variables 171

R

Range 180, 401Reading ASCII data files 65Reciprocal of a surface 264Registered grids 200, 259Remainder 261Removing Quicksurf for Windows 16Required knowledge 9, 10Residual surface operation 267Residual surfaces 267Results surface 23Reverse faults 407Revolved section construction surfaces 162Road building 155Road construction example 367Rubber sheeting drawn entities 185

S

Scale factors during data loading 68Scaling entities in Z 169Scaling inserted blocks 190Scaling surfaces 255Schreiber Instruments 19Screen color fill 131Select by Z

Using 106Selection sets 170SET ACAD= statement 12Shadow analysis 117Show color control 129Show versus Draw 4, 23, 82Sill 180, 401Site design 295Slope

Configuration dialog 225Slope - surface intersections 151Slope analysis 265, 385

Example 386Slope calculation 27

Index Page 441

Index

Slope configuration 150Slope control 201Slope control lines 228Slope intersections 149Slope projection 225Slopes

Absolute slope 265Contouring 385Correcting slope excursions 292Direction 226Linear slope transitions 229Projected slopes 229Projection Side Control 227Splined slope transitions 230Transitions 229Units 219

SmoothingContour polylines 108Surfaces 175

Software requirements 9Solving for an elevation 281Spherical variogram type 179Splicing surfaces 254Splinesegs 109Square root of a surface 262Standard grid method 201Step Size

Intersect slope 228Step size

Drape step 280Stock pile volumes 140Subtraction (-) 260Sun positioning for lighting studies 117, 118Surface colors

Blank color 124By another surface 120By lighting 116By shadow 117By slope in degrees 116By slope in percent 116By viewing direction 120By visibility 119By Z Elevation 116Configuring 122Dialog box 115Disabling 121

Drawing legend 121Example 387Low and high colors 125Method 115Number of colors 124Remap colors command 127Sequence 122Setting a Z value range 124Setting specific color intervals 125Starting color 124

Surface estimation methods 317Choosing the appropriate method 320Geostatistical methods 319Slope-based methods 318Triangulated Irregular Network (TIN) 317

Surface information dialog 45, 53Surface memory 4, 22Surface modification operations 250, 254Surface operations

Absolute slope 265Absolute value 262Addition(+) 260Between mixed surfaces 256Calculation sequence 237Cell count 251Cell size 251Clear parts 242, 247Configuring 237Copy 243, 248Degree slope 265Delete 243, 248Description 245Dialog box 239Division (/) 260Exponential 263Floor 264Grid to Grid operations 259Horizontal translation 255Invoking dialog 93Layer 245Ln 263Load (to results surface) 249Log 263Maximize 237, 258Maximum 262Mechanics of 257

Page 442 Index

Index

Merge 254Minimum 261Move 248Multiplication (*) 260Power of 10 264Read QSB 242Rename 244Residual 267Run Operation button 246Save ( to named surface) 249Scaling in X and Y 255Set 254Splice 254Square root 262Subtraction (-) 260Surface management functions 247Trend 266Trigonometric functions 264Understanding 256Window 252Write QSB 242

Surface operations dialog boxSurface list 240Surface management buttons 241

Surface operations without dialogs 94Surface view

Example 361, 379Examples 157

Surface volume command 138Surface zoom

Using 46Surfaces 3, 21

Analysis of 295Associating layer names 245, 249Changing grid cell count 251Changing grid cell size 251Clear parts 247Clearing parts 242Coloration 114Conical 162Constant surfaces 254Construction surfaces 161Controlling overshoot 203Copying 243, 248Creating patches 164Creating similar geometries 254

Deleting 243, 248Description field 245Detailed listing 243Determining surface-surface intersections 164Editing 287Estimation methods 317Exponential 263For draping upon 211Horizontal translation 255Listing to text screen 250Logarithmic 263Merging surfaces 254Moving average 175Naming 249Of revolution 162Parts 21Parts of 24Perspective view 220Perspective views 97Pick list pop-up 46Planar 162Renaming 244, 248Results surface 23Rotation about Z axis 255Rounding down 264Saving 23Scaling 255Setting the current surface 241Simplification 192Splicing 254Surface for contouring 207Surface list sort 237Surface statistics 245Trend surfaces 203Viewing 95Zooming relative to 96

T

Technical support 19Telephone numbers 19Temporary surfaces 161Terrain Generator 171Text

Height for Post from memory 222

Index Page 443

Index

Height in Post from memory 104Justification for Post from memory 223Justification in Post from memory 104Position for Post from memory 221Position in Post from memory 103Posting problems 107Rotation for Post from memory 222Rotation in Post from memory 104

TGEN command 171TGRD 24, 26

And boundaries 218Contouring on the TGRD 207Definition 28Draping upon 212Example 341, 352, 361, 379Volumes 134Volumes under a TGRD 306

TGRD command 86TIN 24

And boundaries 218Contouring on the TIN 207Definition 26Draping to the planar TIN 211Draping to the TIN using derivatives 212Drawing the TIN perimeter 172Repeated triangulation 275TINs following break lines exactly 272Volumes 134Volumes under a Planar TIN 306Volumes under a TIN with derivatives 134, 306

TIN command 84TIN invisibility 85TINEDGE command 172Transitioning between slopes 229Transitions

Between cross-sections 158Slope 158

Translating surfaces horizontally 255Trend surfaces 35, 203

Trend order 204Trend surface operation 266Trend Type 204

Triangulated Grid (TGRD)Definition 28

Triangulated grid command 86Triangulated Irregular Network 84

Trigonometric functions 264Troubleshooting

Common volume calculation mistakes 315Installation 12

Typeface conventions 8

U

Unit conversions 219User coordinate system and extract 327Utilities

Elevation utilities 167Utility routines 167

V

Vario command 177Variogram

Exponential 179Gaussian 179Histogram intervals 178Hole 180Linear 179Nugget 180Piecewise continuous 180Range 180References for further reading 181Sill 180Spherical 179Types of 400Variogram type 179Variogram window 178

Variogram design 177Examples 399For contaminant data 392

Version of Quicksurf 172, 197Vertical align

Examples 371Vertical align command 152Vertical discontinuities 33Vertical exaggeration

cross-sections 233Vertical profiles

Adjusting 152Creating 145, 147

Page 444 Index

Index

Vertical scale for cross-sections 233Vertical surfaces 363Viewing surfaces 95, 96Viewpoint 98, 220

Examples 157Visibility surface analysis 119Visualization of two surfaces 120Volumetrics 133, 297

Area volume command 139, 310Basis for volume calculation 134Boundary conditions 314Boundary Volume 311Boundary volume command 140Common volume calculation mistakes 315Comparison to Average End Area volumes 314Example 342, 352, 381File output 136, 308Labeling sub-areas 136Partial surface volume 299Positive versus negative volumes 137Practical volume calculations 312Sub-area labels 308Surface volume command 138, 310Surface volume dialog box 133TIN based volumetrics 297Two surface example 135, 307Understanding volume calculation 300Units 219Volume between a surface and a constant 135Volume by Entity command 303Volume calculation 133Volume calculation from surface memory 305Volume of a drawn TIN or grid 141Volume reports 137, 309Volume under a surface 299Volumes between a surface and a constant 307Volumes between surfaces 134Volumes under an entire surface 138Volumes under part of a surface 139

Voronoi diagrams 181

W

Wall constructions 363Window for grid creation 252

Windows installation 14

X

XOR show color 129

Index Page 445

quick surf

Documents

quick installation

dos installation

windows installation

materials available

surface modeling

surface memory

cd rom installation

product quicksurf