final exam review: graphicsahamlin/1100_exam_review_drawing... · 2007. 4. 25. · 1...

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Engineering FundamentalsENG1100 - Session 14B

Final Exam Review:Graphics


Final Exam• Monday, 7:45pm-9:45pm– Section 3: Fisher 329 – Section 4: Fisher 327B

• Format– Cumulative Exam– Multiple Choice– True/False– Work by hand problems– NON-PROGRAMMABLE calculators may be used


Graphical Communication Overview

• We will be:– Drawing– Solid Modeling


Final Exam Topics• Drawing

– Coordinate systems– Isometric and Oblique pictorial sketching– Object Transformations

Translation ReflectionDilation Rotation

– Orthographic ProjectionsNormalInclinedSingle-curved surfaces


Pictorial Sketching: Coordinate Systems• Used to define the locations of points, lines,

and planes in 2 or 3 dimensions.• "Cartesian Coordinate system"

X

Y


3-D Coordinate Systems• Consist of three, mutually perpendicular

axes used to define space• Positive or negative based on the axes– Right Hand Rule determines if a coordinate

system is positive (right-handed) or negative (left-handed)

– 3-D Coordinate systems are generally positive (right-handed)


Coordinate Systems: Right Hand RulePlace your fingers in the direction of the positive x-axis and rotate them in the direction of the y-axis. Your thumb will point in the direction of the positive z-axis.


Coordinate SystemsThe following systems are right-handed (positive).

These systems are left-handed (negative).

X

Y Z

XY

Z

X

Y

Z

X

Z

Y


Pictorial Sketching• Used to portray a 3-D object on a 2-D

sheet of paper.• 3-D axes appear differently when shown

on a 2-D surface.• Standard axes:– Isometric

– Oblique


Isometric Coordinate Axes

Isometric sketches are made as if youere looking down a diagonal a cube


Isometric Coordinate AxesNote: all isometric object surfaces will appear distorted.

Square surface appears as a rhombus

Isometric sketches are made as if you were looking down a diagonal of a cube


Coded Plans: Isometric Sketch from corner C


Isometric Sketching

Guidelines for constructing isometric drawings:0.Draw edge "C".

1.Sketch right or left surface.

2.Draw a surface that shares an edge with the surface just drawn.

3.Continue drawing one surface at a time until the object is complete.

311

2

C

CStep 1 & 2 Step 3 Step 4 ...

Step 4 ...


Oblique Coordinate Axes


Oblique Coordinate AxesNote: Surface parallel to the plane of the paper (the XY plane) is shown in its true shape.

Oblique sketches are made perpendicular to an edge on the object


Oblique Sketching

Oblique sketch from edge DC:


Oblique Sketching• To draw oblique sketches:

1. Draw the first surface completely2. Add lines showing the receding dimension (depth)3. Repeat until the object is complete

• Notice: All receding lines are parallel to one another

3

1

2


Oblique Sketching

Since one face of the object is undistorted, the most irregular face is usually shown in the plane of the paper.


Oblique Sketching

• 3 types of oblique pictorials.• Cabinet pictorials are the most common.


Object Transformations

TranslationDilationRotationReflection


Object Transformations:

Translation• Sliding of an object

in the X, Y, and/or Z-directions.

• Object looks the same, only it is in a different position with respect to the origin.



DilationEnlargement or shrinking of an object, i.e. a change in volume.

A) r = 1 C) r = 1/2B) r = 3



DilationThe dilation factor = r• Indicates the change in the dimensions

of the object.

Note: ALL object dimensions are changed by the same factor r.

• 3x3x3 cube with r = 2 will measure 6x6x6• 3x3x3 cube with r = 1/3 will measure 1x1x1• 2x3x1 object with r = 2 will measure 4x6x2



RotationTurning of an object about a straight line (axis of rotation)



Rotation• If the object is turned counter-clockwise (on the axis,

looking towards the origin!), the rotation is positive.

• A clockwise rotation is a negative rotation.

• A 90o turn is one rotation.

Positive



Rotation

Right Hand Rule:

• Point the thumb of your right hand down the axis of rotation.

• Your fingers will curl about the axis in the positive direction.



RotationRotations are denoted by a system of arrow coding.

• A right-facing arrow denotes a positive 90° rotation.

• A left-facing arrow denotes a negative 90° rotation.

• The axis about which the arrow is rotated is shown at the right end of the arrow.

Y

X

Positive 90° rotation about the Y-axis

Negative 90° rotation about the X-axis



RotationFor rotations about more than one axis, arrows are placed in the order in which the rotations are performed.

1) Positive 90° rotation about the z-axis2) Negative 90° rotation about the x-axis.

ZX

Y

X

X

1) Positive 90° rotation about the y-axis2) Positive 90° rotation about the x-axis3) Negative 90° rotation about the x-axis.



Rotation• For multiple rotations about the same axis, use

an arrow for each rotation of 90°.

XX

Y

Positive 180° rotation about the x-axis

Negative 270° rotation about the y-axis

YY



RotationThe final orientation of the object is dependent on the order in which the rotations were performed.

XY

YX



RotationSometimes one set of rotations can be replaced by a simpler set.

is equivalent to

is equivalent to

YY YY

XZZY

ZX



ReflectionA reflection across a plane displays the object’s mirror image.

ReflectionPlane



ReflectionPlane of symmetryoccurs if the objects on both sides of the plane are mirror images of each other.


Orthographic Projection

• Ortho - Greek word meaning perpendicular• Show the views of an object projected in 2-D• Usually the top, front, and right side views

top

front right



• Imagine the object is surrounded by a glass cube.

• Object surfaces are projected onto the faces.


Orthographic Projection● Unfold the cube

so that it lies in a single plane

● Three views of the object are now visible on the same plane in space

Fold lines



When the glass cube is unfolded: Front view: Height and Width

Top view: Width and Depth Right view: Depth and Height H H

W

W

D

D



Align views with each other (features project from one view to the next)


• Parallel to one of the six glass panes of our transparent cube

• Perpendicular (normal) to the projectors to/from that plane

Shown true size and shape in the view that they are parallel to

Seen as edges (lines) in the other principal viewsA

B

Orthographic Projection:

Normal SurfacesB

A



Hidden Lines

Hidden Line (Dashed lines; can't be "seen in that view)

Visible Line (Solid lines, can be seen in a given view, aka: Object Lines)



Inclined Surfaces• Not parallel to any of the principal views• Appear as area in two views, as edge in third view

• Area views are foreshortened• Basic shape is maintained


Constructing an isometric view of an inclined surface:1. Locate the endpoints of each inclined edge 2. Draw a straight line between them

Isometric View:

Inclined Surfaces


Select an orientation that makes the inclined surface appear as a visible area (whenever feasible)

Isometric View:

Inclined Surfaces: Constructing Isometric Views

Correct Incorrect


Constructing a missing orthographic view of an inclined surface:

1. Locate each vertex (edge to edge intersection) in the given views

2. Project to the construction view

Vertices are connected to create edges as in the other views.


Inclined Surfaces



Single Curved Surfaces



Single Curved Surfaces• Surfaces having curvature about one axis• Generated by revolving a line about an axis



Single Curved Surfaces

Consider a cylinder: • Ends are circles in one

orthographic view• Other orthographic views are

rectangular• Rectangle width is equal to

the cylinder diameterNote: when projecting into

orthographic views, the curved area is bounded by circular edges.



Single Curved SurfacesBecause a curved surface is rectangular in two views, you MUST indicate the radial center with centerlines.

•Crossing centerlines are used in the circular view.

•One centerline is shown in each areal view.



Single Curved SurfacesUsually, the two orthographic views that show the cylinder as a rectangular area are projected from the circular view.

Right view projected from the front view

Right view projected from the circular view



Single Curved Surfaces-Holes

Holes follow the same rules as external curved surfaces, except the cylindrical boundaries are shown as hidden lines.


Orthographic Projections

• If you have a choice for selecting Front, top, right side views– Select views to show the object’s profile– Select views to minimize hidden lines


Final Exam Topics• Unigraphics (NX 3.0)

– Units– Constraints (Dimensional and Geometric)– Sketch Based Modeling Approach– Boolean Operations (Cut, Intersect, Join)– Drafting Application


UGNX software• UGNX is an integrated modeling package– Integrated means: You can model a part,

create a drawing from it, analyze it, and set up manufacturing tool paths - all within the same package

• In ENG1100/ENG1102 we will be focusing on 3D modeling and drafting


File Management• All UGNX files have a .prt extension

even though they may be more than just parts.

• Things that can be in a .prt file include– Solid Bodies (Models)– Assemblies– Drawings– Analysis Info– And more


Software Structure• UGNX is organized into: – Applications: Gateway, Modeling, Drafting

(and others)– Sub-Applications: Sketcher, Assembly

(are accessed from the Modeling application)

• When a part file is opened or created, the Gateway application is entered.– Gateway: used to review file information and

manage files• To create or edit a solid body the

Modeling application is entered


UGNX Startup• Launch NX3.0 from

the “Start” button• Select either New

or Open from the File menu

• Name a new file, or choose an existing one

• Choose Units!• This starts the

Gateway application

• (See next slide)


WARNING – CHOOSE UNITS NOW!

Until Death Do You Part!!


Icon to open ModelingThis is the Gateway application

Tool BarsResource Bar

Cue, Status line – PAY ATTENTION HERE!


Sketch Based Modeling

• ENG1100 will introduce “Sketch Based”modeling techniques

• ENG1102 will introduce “Feature Based” modeling

• Each technique has its place in 3D modeling


Why Sketch?

• Sketching gives a high level of control over feature creation

• Sketching allows efficient editing of complex features

• Consider sketching when feature based modeling can’t capture the design intent

• Sketches can be extruded or revolved into a 3-D feature


General Modeling Method using the Sketcher

1) Create 2-D Sketch

2) Constrain Size & Shape

3) Make 3-dimensional using extrude (cut, revolve, sweep, etc.)


Extrusion• Materials processing term:– material is forced through a die of a given shape

resulting in an object of constant cross-section• Example: – Forming complex steel cross-sections is done by

applying pressure to molten steel and forcing it through a die

– Analogous to a Play-Dough Fun-Factory


Sketch – opens the Sketch function

Extrude

Hole

This is the Modeling application


Click the flag to finish your sketch

Note the sub-application name

Sketching tools


As a Team....(switch drivers)

• Extrude the shape you created– First you must “finish” your sketch

(click the “finish flag” icon)– Use the extrude icon and follow

the cue directions– Use the default extrude distance

or use the arrowhead “handle” to set

Extrude


Extrude Dialog

Change Extrude Direction

Boolean Operators

Extrusion Distance

Extrude Dialog Icon


Sketching on Surfaces (other than original 2-D sketch)

• Go into Sketcher • Select surface of

object to draw on• Draw and

“finish” new sketch

• Extrude (new part, cut, join, or intersect) new sketch in Modeler


Sketching on Surfaces

• Your 2-D sketches can extend beyond the borders of the surface itself

Circle Extends BeyondSurface Border

Makes Semi-Circular Cutout


General Modeling Method using the Sketcher

1) Create 2-D Sketch

2) Constrain Size & Shape

3) Make 3-dimensional using extrude (cut, revolve, sweep, etc.)


Need to Modify Your Sketch?

• Do NOT simply select sketcher icon and select plane as you did previously – this creates a NEW and SEPARATE sketch

• Instead, select your original sketch


How to Modify Original Sketch#1 Need to go back to original sketch

• Three ways to do this– Double-click (Left mouse button) on appropriate sketch in

the Part Navigator (Sketch “Sketch 000”)– Position cursor over part in graphics window until outline of

original sketch appears (in pink) – double click left mouse button

– Go to sketcher as when beginning a new sketch, but once in sketcher, select the correct sketch number (next to the checkered flag) to edit


2-D Sketch Constraints

1. Dimensional Constraints• Control Size• Length, angle, diameter, etc.

2. Geometric Constraints• Control Shape• Horizontal, Parallel, Coincident, Tangent,

Angular, etc.


Dimensional Constraint ToolsIn Sketcher Mode:• Inferred• Horizontal• Vertical• Parallel• Perpendicular• Angular• Diameter• Radius• Perimeter

To change decimal places/size of dimension text– Preferences -> Sketch ->


Dimensional Constraints

• Does typing in the length as you sketch dimensionally constrain your part?

• NO – this will create the correct size now, but you need to add dimensional constraints in order to more easily modify later


Drawing your shape to scale does not constrain your shape!!!!!


Geometric Constraints

• Control the shape of sketch• Options appear as you select curves to

create the constraint


Geometrically dimension your shape

• Delete all but one of your length dimensions and make the four sides equal length

• Try to drag the sides/vertices of your shape around

Make sure this is turned on

Use this to create yourgeometric constraints –to make lines equal length,first click on one line, thenthe second line

Make your bottom line a horizontal line


Create a Drawing1. Create part in

modeling application

2. Switch to drafting application

3. Insert Sheet form select:

• Paper size• Scale• Units


Create a Drawing• 4. Add Base View

• Insert > View > Base View

• MB3 on drawing border > Add Base View

• Icon on sidebar• Part Nav MB3 on

drawing sheet > Add Base View


Create a Drawing

• 5. Choose View Options

• Style (hidden lines)

• View (front/iso)• Scale

• 6. Place Base View

• 7. Add Projected Views

• 8. To get an isometric, Add Base View


Adding Dimensions• For many dimensions, just use

the Inferred dimension tool• To be more specific, pick the tool

that best selects your part geometry

• Dimensions are fully associatedto solid, i.e. if you change the model (in modeling) dimensions (in drafting) automatically update


Adding Notes (Annotation)

• Select Annotation Editor • Insert > Annotation • Icon

• Enter Text in Edit Window

• Place Text

final exam review: graphicsahamlin/1100_exam_review_drawing... · 2007. 4. 25. · 1...

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