it's a 3d world after all · the view toolbar gives us tools to quickly switch to any of our...

Walt Disney World Swan and Dolphin ResortOrlando, Florida

11/30/2005 - 1:00 pm - 2:30 pm Room:S. Hemispheres (Salon 4) [Lab] (Dolphin)

It's a 3D World After All

Solid with 2D line work...Not so solid with AutoCAD 3D solids... In a 3D world we can visualize and communicate designs faster and more effectively with 3D models in the AutoCAD environment. In this course, learn basic commands allowing you to model most anything, from architectural to mechanical, and bring your designs into a whole new world. For those interested in this course, you might follow it with, "It's a Material World After All".

GD33-4L

About the Speaker:

Alexander Wood - WGM Group IncShaan Hurley (Assistant); Michael Beall (Assistant)and

Alex has more than 14 years experience with AutoCAD, starting with Release 9. He holds Autodesk certification for nearly all Autodesk products. Alex works as IT manager for WGM Group Inc, a Montana-based engineering and land planning firm. He also has 4 years of experience as technical manager at an Autodesk System Center. Alex is expert in numerous fields, including utilities drafting, civil/environmental engineering design, 3D hydraulic/electric machine design and fabrication, CADD project management, architectural drafting and visualization, CADD services systems/personnel management, and Autodesk product support. [email protected]

GD33-4L It’s a 3D World After All

2

Course Outline: UCS Discussion and Basic UCS Manipulation

• The XY Plane

• The View Toolbar

• The 3-Point UCS

• The UCS II Toolbar

Using Polylines and PEDIT

• The importance of CLOSED Polylines

• PEDIT – Join and Close

Basic Solid Creation

• Primitives

• The Shade Toolbar

• Extrude – Height of Extrusion, Path

• Revolve – Axis of Revolution, Angle of Revolution

Basic Solid Editing

• Union

• Subtract – Solids to Subtract From, Solids to Subtract

• Rotate3D – First Point on Axis, Second point on Axis

• Align

3D Scene Setup

• 3DOrbit

• Named Views

Extras

• AutoCAD System Variables that Affect 3D Operations


3

UCS Discussion and Basic UCS Manipulation The XY Plane This is an image of the AutoCAD 2000 (and later releases) UCSICON.

How many of us have turned this off in the past to get it out of the way?

In AutoCAD 3D, the UCSICON is going to be your new best friend.

In Plan or Top views it shows the direction of the X and Y in AutoCAD’s Model Space.

The Z direction is assumed to be pointing straight at us as we view the AutoCAD drawing area in Model Space in a Plan or World view.

When switching to 3D views, the UCSICON changes to show us, in 3-Dimensions, the directions of the X, Y, and Z vectors.

Here we can see the UCSICON in a 3D view.

Also note that the AutoCAD Crosshairs align to the XY Plane.

A general rule of thumb:

When we create or modify objects in Model Space we are natively working in the XY Plane.

However, using some basic AutoCAD tools, we are able to manipulate, or flip, the XY to whatever direction or plane we need to work in.

There are three basic tools we will learn in this session that we can use to manipulate the UCS;

#1 - The View Toolbar

#2 - The 3-Point UCS command

#3 - The UCS II Toolbar


4

The View Toolbar The View Toolbar can be found in the following places.

Right-click on any existing AutoCAD Tool Button and choose the View Toolbar option from the shortcut menu. Or use the View Menu => Toolbars and checking the View Toolbar checkbox.

Additionally, one can customize this Toolbar and add the 3DOrbit button (a command which will be discussed later in this session).

The View Toolbar gives us tools to quickly switch to any of our standard Orthographic views (Top, Front, Left, etc.) and to also switch to four standard Isometric views (SW, SE, NE, NW).

When switching to the Orthographic views, AutoCAD automatically aligns the UCS or the XY Plane to that view.

Note: The UCSORTHO variable controls the behavior of the UCS when switching views. UCSORTHO=0, UCS will not align to the view. UCSORTHO=1, UCS will align to view.

Remember we natively work in the XY Plane but that plane can be flipped up to any view in which we want to work.

Extra Note: If one uses the View Toolbar to switch to an Orthographic view and then to switch to an Isometric view, the UCS of the Orthographic view will be current.

For Example, switching to the Front Orthographic view from the View Toolbar will align the UCS to that view. If one then switches to the SW Isometric view the UCS will still be aligned to the Front.

We can use the UCS II Toolbar to flip the UCS back to Top or to any other Orthographic UCS. This will be covered later in this session.

Front Orthographic view of wedge object

Note that the UCS aligns itself to this view

SW Isometric view of wedge object

Note that the UCS is aligned to the previous Front Orthographic view


5

Exercise #1 – Using the View Toolbar 1. Open the drawing file ‘GD33-4L-EX01.dwg’

2. Confirm that the UCSORTHO variable is set to 1. Type UCSORTHO <Enter> at the command line and set the value to 1

3. Confirm that the View Toolbar is available. If it is not already on-screen, Right-Click on any AutoCAD tool button and select the View Toolbar from the shortcut menu.

This drawing shows an arrangement of basic solid primitives in Model Space.

4. Using the View Toolbar, switch to the SW Isometric view.

This command can also be found under the View Menu => 3D Views => SW Isometric.

We should now see the SW Isometric view.

Note here that the UCS is aligned to the last Orthographic view, the Top View.

We can Pan, Zoom, and Draw or Modify objects in this, and any other view.

Remember that as we draw and modify objects we are still always working in the XY Plane.

5. Use the View Toolbar to switch to the Front View.

We are now looking at the Front Orthographic view of our objects.

The UCS automatically aligns to the Front.

This essentially flips the XY Plane to that view.

If you were to draw new objects or move or copy existing objects you would be working in the XY Plane.

Using the Polar tool and these Orthographic views we can easily manipulate the location of our objects.

For example, if we wanted to move the wedge up 2 units, we would execute the MOVE command, select the object, select a base point, and then use Polar and Direct Distance Entry to move the object up exactly 2 units.

If you switch now to an Isometric View you will see that the UCS is still aligned to the Front.

6. Close the drawing file ‘GD33-4L-EX01.dwg’ and, when prompted to Save Changes, select No.


6

The 3-Point UCS Command The 3-Point UCS command can be found in the following places.

The UCS Toolbar:

From the Tools Menu => New UCS => 3 Point

Or at the Command Line by typing:

UCS <Enter>

3 <Enter>

With the 3-Point UCS command we can define 3 points that represent the origin of the UCS (0,0,0), the direction of the Positive X-Axis, and the direction of the Positive Y-Axis.

AutoCAD will determine the direction of our Positive Z-Axis from that information.

This additionally allows us to align the UCS directly with or along a specific object.

Defining the Origin using an OSNAP

Note: Using the Polar Tool or OSNAPs when defining the Positive X and Y Axis can have an effect on the accuracy of the aligned UCS.

Defining the Positive X-Axis using Polar

Note: Using the Polar Tool or OSNAPs when defining the Positive X and Y Axis can have an effect on the accuracy of the aligned UCS.

Defining the Positive Y-Axis using Polar

The finished result – The UCS is now aligned to the object.

We can use this same method to align the XY Plane to a specific side or face of an object. This command can be extremely useful in aligning the UCS to an angular face such as with a wedge shape.


7

Exercise #2 – The UCS 3-Point Command 1. Open the drawing file ‘GD33-4L-EX02.dwg’.

This is a basic drawing with a wedge drawn in Model Space and looking at the Top or Plan view.

2. Using the View Toolbar, switch to the SE Isometric view.

Note that the UCS and the crosshairs are aligned to the previous Orthographic view, in this case, the Top view.

Using the 3-point UCS command allows us to align the UCS and the XY Plane to angular or non-orthographic faces.

In this case, we may want to add a feature to the angled face of the wedge.

By aligning the XY Plane to the angled face we can then draw and manipulate object features along that plane.

3. Start the UCS 3-point command.

This can be found on the UCS Toolbar, from the Tools Menu => New UCS => 3 Point, or at the Command Line by typing, UCS <Enter> 3 <Enter>.

You then are prompted to, Specify new origin point <0,0,0>:

4. Using the ENDpoint OSNAP, select the lower left-hand corner of the angular face of the wedge.

This changes the 0,0,0 origin point to that corner of the object.

5. You will then be prompted to, Specify point on positive portion of X-axis:

6. Using the Polar Tool, define the positive X-axis along the front edge of the wedge. You can use the ENDpoint OSNAP on the lower right-hand corner of the angular face as well.

7. You will then be prompted to, Specify point on positive-Y portion of the UCS XY plane:

8. Using the ENDpoint OSNAP select the top left-hand corner of the angular face.


8

The UCS and XY Plane will now be aligned along the angular face with the positive Z-axis pointing perpendicularly away from the face.

The crosshairs will be aligned along the current UCS as well.

This now allows us to work in that exact plane in order to create and modify objects along that angular face.

We will cover the creation and modification of such objects later in this session.

9. Close the drawing file and choose No when prompted to save changes.

Extra Note: If the UCSICON does not immediately snap to your newly designated origin point there is a UCSICON Display command to correct that.

Under the View Menu => Display => UCS Icon there is a check option for Origin.

If Origin is checked then the UCSICON will jump to the designated Origin point (by default in AutoCAD this is 0,0,0).

If Origin is not checked then the UCSICON will remain in the lower left-hand corner of the AutoCAD drawing area.

The variable UCSFOLLOW determines how UCS changes affect your display. If UCSFOLLOW is set to <0> then changes to the UCS will not affect the display. If UCSFOLLOW is set to <1> then AutoCAD will generate a plan view whenever there is a change to the UCS. For most 3D work, UCSFOLLOW should initially be set to <0>.


9

The UCS II Toolbar The UCS II Toolbar is invaluable when working in 3D.

To reiterate (again), when we draw or modify objects in AutoCAD we work in the XY Plane. However the XY Plane can be ‘flipped’ to any view plane in which we wish to work.

When using the view toolbar to change to the standard Orthographic views, AutoCAD automatically aligns the UCS or the XY Plane to the current view.

When working in Isometric views we can use the dropdown menu on the UCS II Toolbar to modify or change the UCS and the XY Plane to the Orthographic plane we want to work in.

The UCS II Toolbar can be found by right-clicking on any AutoCAD Tool Button and selecting the UCS II option from the shortcut.

Using this dropdown menu we can quickly set the Orthographic UCS to a specific plane.

As we look at the AutoCAD drawing area, we are looking at a Top (Plan) view. This is also considered a User Coordinate System (UCS). The World Coordinate System (WCS) is the default ‘fixed’ coordinate system that is the basis for all AutoCAD drawings.

Here we see our wedge in the SE Isometric view.

Initially, when switching directly to the Isometric view from Top (Plan), the UCS will be set to Top. This can be seen instantaneously in the UCS II Toolbar dropdown menu.

By using the UCS II Toolbar we can quickly switch to another Orthographic plane.

In this image the Front UCS is set as the current UCS.

Notice the XY Plane and the crosshairs that align to that plane. This would allow us to draw new features in that plane or to modify existing objects without having to use 3D coordinates.

For example, to move this object up 2 units in the Z plane while in a Top UCS, we would have to use the coordinate entry in the MOVE command 0,0,2. Using the Front UCS in this case we could simply use Polar and Direct Distance Entry.


10

Exercise #3 – Using the UCS II Toolbar 1. Continue with the drawing file ‘GD33-4L-EX02.dwg’ or open the ‘GD33-4L-EX03.dwg’ drawing file.

Here we have our wedge with the UCS aligned along the angular face.

2. Bring up the UCS II Toolbar.

This can be done by right-clicking on any AutoCAD Tool Button and selecting UCS II Toolbar from the shortcut menu.

The ‘current’ UCS in the UCS II dropdown will show an ‘unnamed’ UCS.

By using the UCS command, these ‘custom’ UCS settings can be saved and restored for later use.

3. Using the UCS II Toolbar dropdown menu, select the Front UCS.

The UCS and the XY Plane will ‘flip’ to the Front Orthographic UCS.

4. Experiment with the other Orthographic UCS options in the UCS II Toolbar dropdown menu.

Note that with each option the Crosshairs and the XY Plane align themselves to the selected UCS.

Front UCS in Isometric view

Right UCS in Isometric View

5. Close the drawing file and, when prompted to Save Changes, select No.


11

Using Polylines and PEDIT The Importance of CLOSED Polylines In AutoCAD 3D there are a number of ways we can create solids to develop our custom objects and assemblies.

Later in this session we will learn about basic Primitive shapes that can be combined to create these custom assemblies.

We can also use Polyline shapes to create more custom shapes.

When using Polylines to create custom solids, it is important to use the Close option of the Polyline command.

If a Polyline is not “Closed” then the solid creation commands (i.e. Extrude, Revolve) will fail.

When you manually close a Polyline, meaning connecting your last segment back to the first segment or the initial starting point using a basic OSNAP (most likely an ENDpoint), this will create what is known as a “Zero Length Polyline”.

This can also cause solid creation commands to fail and other issues downstream such as corrupt drawings or the inability to share those solids with other 3D software packages.

Incorrect: Connecting the last segment of a Polyline to the first segment manually; i.e. using an ENDpoint OSNAP.

Correct: Connecting the last segment of a Polyline to the first segment by right-clicking and selecting Close.


12

PEDIT – Join and Close We can also use the PEDIT command to Join multiple Line or Polyline objects into a single Polyline object and additionally use the Close command in PEDIT to ‘Close’ open Polylines.

A Polyline may appear to be physically closed in our drawing area but it may not have the property of being a truly closed Polyline.

We can use the Properties dialog or the PEDIT command to see if a Polyline is actually closed.

By selecting an exiting Polyline, right-clicking, and choosing Polyline Edit from the shortcut menu, we will see a number of command options at the Command Line.

Select the Polyline, right-click, and choose Polyline Edit from the shortcut menu.

If the Command Line option Close is displayed, then the Polyline is not a truly closed object.

Close the Polyline by right-clicking and selecting Close.

If the Command Line option Open is displayed, then the Polyline is truly closed and we should be able to continue with the solid creation commands such as Revolve and Extrude.


13

Basic Solid Creation Solid Primitives Most creation commands for Solid Primitives will be found on the Solids Toolbar.

We can use a number of different ‘Solid Primitives’, or basic solid shapes, to begin the process of creating custom or more complex 3D models. By mentally ‘breaking down’ a complex assembly into its simpler parts and creating those Primitives, we have the building blocks for our 3D model.

For instance, two Cylinders and a Sphere could start a basic model of a fire hydrant,

Or a Box and four Cylinders could be used to create a base plate.

Solid primitives are created as any other basic element in AutoCAD, by defining the starting or location points and then defining properties, such as radius and height for a cylinder, or the length, width, and height of a box.

We can then use basic AutoCAD commands, such as MOVE and ROTATE, along with some 3D commands, such as ROTATE3D and ALIGN, to position the pieces of our assembly.


14

Exercise #4 - Creating Solid Primitives 1. Open the drawing file ‘GD33-4L-EX04.dwg’.

Here we see a blank drawing looking at a basic SE Isometric view in Model Space.

2. Confirm that the Solids Toolbar is visible.

If it is not visible, right-click on any available AutoCAD Tool Button and select the Solids Toolbar from the shortcut.

3. Select the ‘Cylinder’ primitive – the 3rd button from the left on the Toolbar.

AutoCAD will prompt you to, Specify center point for base of cylinder or [Elliptical]:

4. Use the absolute coordinate of 0,0,0 for the center point of the cylinder.

AutoCAD will prompt you to, Specify radius for base of cylinder or [Diameter]:

5. Type in the value 4 to create a 4-unit radius cylinder.

AutoCAD will then prompt you to, Specify height of cylinder or [Center of other end]:

6. Type in the value 18 to create a cylinder with the height of 18-units.

7. Zoom out to see the entire object. We should now see a basic cylinder primitive in our drawing area.

8. Start the ‘Sphere’ primitive command. This should be the 2nd button from the left on the Solids Toolbar.

AutoCAD will prompt you to, Specify center of sphere:

9. Using the CENter OSNAP, select the top center point of the cylinder.

Note: An important feature of AutoCAD solids is that they support most of the obvious or logical OSNAP points. For instance, the Cylinder will have a CENter OSNAP at each end as well as QUAdrant OSNAPs along those same circular ends.

AutoCAD will then prompt you to, Specify radius of sphere or [Diameter]:

10. Type in the value 4 for a 4-unit radius sphere or you can simply use a QUAdrant OSNAP along the circular edge of the top end of the cylinder.

Our Sphere is now aligned with the top of the cylinder at its center and at the same radius.

Using these basic primitives, we have the building blocks to create more complex shapes.

This could be the beginning of something as basic as a fire hydrant or a garbage can.

11. Try using the ‘Box’ primitive. This is the 1st button on the Solids Toolbar.


15

With the Box primitive, AutoCAD will prompt you to, Specify corner of box or [Center]:

12. In this case, right-click in the drawing area and select the Center option from the shortcut menu. You can also type CE at the Command Line and then press <Enter>.

13. Using the CENter OSNAP, select the center of the bottom circular part of the cylinder.

AutoCAD will then prompt you to, Specify corner or [Cube/Length]:

The Cube option allows you to type in one value and AutoCAD will create a Cube shape based on that single value.

14. For this model, right-click in the drawing area and choose the Length option from the shortcut. Additionally you could type L at the Command Line and press <Enter>.

This will allow us to specify an exact Length, Width, and Height for our Box.

15. For the Length value type 12 and press <Enter>.

16. For the Width value type 12 and press <Enter>.

17. For the Height value type 1 and press <Enter>.

We should now see our Box, or in this case, what could represent a ‘Base’ for our model, centered at the bottom of our cylinder.

Just as we do in normal AutoCAD 2D drafting we use real-world units to create our objects and models.

This is a simple arrangement of shapes that could represent a number of different real-world objects.

Again, by adding more primitives, custom shapes, and using basic Solids editing we can create much more complex models.

18. You may leave this drawing open for the next Exercise, Exercise #5 (for the Shade Toolbar) or you may close the ‘GD33-4L-EX04.dwg’ drawing file and choose No when prompted to save changes.


16

The Shade Toolbar This is a diversion from the creation of Solids to the basic visualization of the solids.

By using the View Toolbar we can look at our 3D objects or models from a number of different Orthographic or Isometric views.

So far we have been looking at these objects in a ‘Wireframe’ Shade mode. This represents our 3D objects in a transparent mode, showing only a wireframe of the model.

The Shade Toolbar gives us some other basic visualization modes including Hidden and Shaded.

The Shade Toolbar is available using the standard methods, either by right-clicking on any AutoCAD Tool Button and selecting the Shade Toolbar from the shortcut menu or by using the View

Menu => Toolbars option and checking the Shade Toolbar checkbox.

As taken from the AutoCAD Help Menu, from Left to Right, the Shade Toolbar options are:

2D Wireframe - Displays the objects using lines and curves to represent the boundaries.

3D Wireframe – Also displays the objects using lines and curves to represent the boundaries but will also show colors that have been applied to edges (this is an option in Solids Editing but is not covered in the scope of this course).

Hidden - Displays the objects using 3D wireframe representation and hides lines representing back faces.

Shaded - Shades the objects between the polygon faces. The objects appear flatter and less smooth than Gouraud-shaded objects.

Gouraud Shaded - Shades the objects and smoothes the edges between polygon faces. This gives the objects a smooth, realistic appearance.

Flat Shaded, Edges On - Combines the Flat Shaded and Wireframe options. The objects are flat shaded with the wireframe showing through.

Gouraud Shaded, Edges On - Combines the Gouraud Shaded and Wireframe options. The objects are Gouraud shaded with the wireframe showing through.

These are also know as Shademode options and are also available under the View Menu => Shade option.

Using the new Shaded Viewport plotting options introduced in the Autodesk 2004-based products we are now able to use these Shademode options, in a Viewport, on a Layout and print them as we see them (WYSIWYG).

You can select these options through the properties of the Viewport shown here from the shortcut menu.


17

Exercise #5 – The Shade Toolbar 1. Continue with the ‘GD33-4L-EX04.dwg’ drawing file or open the ‘GD33-4L-EX05.dwg’ drawing file.

This shows the Cylinder, Sphere, and Box primitive model created in Exercise #4.

2. Confirm that the Shade Toolbar is visible.

3. Select the Flat Shaded button. This is the 4th button from the left on the Shade Toolbar. You can also get to this option under the View Menu => Shade => Flat Shaded

Note the appearance of the objects

Changing the color of the objects or the color of the layer that the object is on (best practice) changes the appearance of the shaded objects.

By using the ACI colors (AutoCAD Color Index) or the newly available True Color options we can give our objects a more realistic look.

4. Select the Gouraud Shaded, Edges On button on the Shade Toolbar.

Note the change in the appearance of the objects.

Although it might be quite subtle, you should see how the Gouraud Shaded option has a smoother overall feel.

The Edges On option highlights the edges of the Wireframe that make up the solid.

5. Experiment with the other options on the Shade Toolbar and note how each option changes the appearance of the 3D model.

Note that in a Shaded mode, the UCSICON also changes in appearance to more of a 3D look.

While working with your models, system performance is increased while working in Wireframe.

Switch to the 2D Wireframe Shademode while working with your 3D elements then use Flat or Gouraud Shade for quick visualizations or quick proofing for Rendering.

6. Close the ‘GD33-4L-EX04.dwg’ drawing file and choose No when prompted to save changes.


18

Extrude – Creating Custom Shapes from Polylines Another way to create custom solids or more complex shapes is by using the Extrude command on a Closed Polyline outline of an object.

As mentioned before, it is important that the Polyline outline is truly Closed.

This is a great way to use even pre-existing 2D geometry to start building 3D models.

The Extrude command by default adds a 3rd Dimension to a Polyline outline.

For instance, by using the Extrude command on this Polyline shape, we can create a custom object that would take much longer to try to create with basic primitives.

After the Extrude command we would see an object with true 3D solid qualities.

Wireframe Shademode

Gouraud Shaded Shademode

The Extrude command can also be used on Polygon Shapes (essentially Closed Polylines) as well as with Circles (to create a Cylinder) and Ellipses.


19

Extrude – Creating Custom Shapes from Polylines The Extrude command can be found on the Solids Toolbar as well.

It can also be found under the Draw Menu => Solids => Extrude or by typing EXT <Enter> at the Command Line.

After you have your Closed Polyline shape, you can execute the Extrude command, select the object, and then specify an Extrusion Height numerically or by picking points on screen.

AutoCAD will prompt you to, Specify angle of taper for extrusion <0>:

With an AutoCAD Extrusion we can specify a Taper or a Draft angle along an Extruded solid.

Using a custom Polyline outline of a shape and Extruding it using a 10 degree Taper angle we would get the following 3D object.

The Extrude command also has a Path option, allowing us to Extrude an object along a pre-drawn Polyline path. This Polyline path is not required to be closed; however the shape that you extrude along that path must still be a closed object.

My favorite example of this is to Extrude a circle along a Polyline sketch of a paper clip.

1. The Polyline path

3. The final shape as an extrusion and Gouraud Shaded

2. A circle drawn at the end of the path (this is accomplished by using the UCSII toolbar to change the UCS to an Orthographic setting perpendicular to the path)


20

Exercise #6 – Using the Extrude Command 1. Open the drawing file ‘GD33-4L-EX06.dwg’.

This is a Closed Polyline outline of what could be a basic gasket with Circle objects representing the holes through the gasket.

We will Extrude both the outline and the holes. Later we will learn how to Subtract the holes in order to punch the holes through the outer object.

Initially we might want to confirm that the Polyline is truly closed using the Properties dialog or PEDIT, as discussed on Page 12 of this document.


3. Start the Extrude command. This is the 7th button from the left on the Solids Toolbar.

You can also execute this command from the Draw Menu => Solids => Extrude or by typing EXT <Enter> at the Command Line.

AutoCAD will then prompt you to, Select objects:

4. Select both the circles and the Polyline outline. We will Extrude them all at the same time and to the same extrusion height.

5. Right-click or press <Enter> to confirm the selection and to continue with the command.

AutoCAD will now prompt you to, Specify height of extrusion or [Path]:

Here we can put in a numerical value or pick two points on screen to represent the height.

6. Type 0.125 at the Command Line and press <Enter>.

7. When prompted to, Specify angle of taper for extrusion <0>: press <Enter> or right-click to accept the default value of <0>.

The objects will be Extruded to the height of 1/8”.

8. Close the ‘GD33-4L-EX06.dwg’ and choose No when prompted to save changes.


21

Exercise #7 – Extruding Along a Path 1. Open the drawing file ‘GD33-4L-EX07.dwg’

This drawing has two basic Polyline ‘paths’, one with a rectangle already drawn perpendicular to the path and one Polyline representing the infamous paperclip.

We will draw the circle for the paperclip path using an Orthographic UCS.

First we will Extrude the Rectangle along the predrawn path.

2. Start the Extrude command. When you are prompted to Select Objects, select the rectangle and then right-click or press <Enter>.

AutoCAD will then prompt you to, Specify height of extrusion or [Path]:

3. Right-click and select Path or type P at the Command Line and press <Enter>.

4. When you are prompted to, Select extrusion path or [Taper angle]:, select the Polyline path and then right-click.

AutoCAD will Extrude the rectangular object along the selected path.

5. Set the Shademode to Gouraud Shaded by clicking the Gouraud Shaded button on the Shade Toolbar.

This could represent part of a downspout on a rain gutter.

6. Zoom in on the paperclip outline.

Here we need to draw the object that we want to Extrude along the path.

We will accomplish this by flipping the UCS perpendicular to the path.


22

7. Zoom in on the outside end of the outline.

8. Confirm that the UCS II Toolbar is visible.

If we were to simply draw a Circle object it would be drawn in the XY plane. This would create a circle in the same plane as the outline.

Instead we will use a different UCS to flip the XY plane perpendicular to the path.

9. In the UCS II Toolbar, use the dropdown to choose the Right UCS.

Note that the UCSICON and the crosshairs are aligned to that UCS.

10. Start the Circle command.

When prompted to, Specify center point for circle or [3P/2P/Ttr: use an ENDpoint OSNAP to select the outside end of the outline.

You will then be prompted to, Specify radius of circle or [Diameter]:

Note: There is a limitation to the Extrude Path option. This is that the final extruded shape cannot be ‘self-intersecting’.

In this example we have to make sure that the Circle is small enough that it does not intersect itself as it extrudes along the path.

11. For the Radius value of this Circle type 0.25 and the right-click or press <Enter>.

We should now see a circle drawn perpendicular to and at the end of the outline.

12. Confirm that the Solids Toolbar is visible then start the Extrude command by selecting the Extrude button.

13. When prompted to Select objects:, select the Circle then right-click or press <Enter> to continue with the command.

AutoCAD will then prompt you to, Specify height of extrusion or [Path]:

14. Right-click and select Path or type P at the Command Line and press <Enter>.

15. When you are prompted to, Select extrusion path or [Taper angle]:, select the Polyline path and then right-click.

AutoCAD will Extrude the Circle along the selected path creating our paperclip solid.



23

Revolve – Creating Custom Shapes from Polylines Another command we can use to generate more complex objects is the Revolve command.

Revolve can be used to create symmetrical revolution objects in a similar manner to a wood or metal lathe.

The Revolve command can be found on the Solids Toolbar, under the Draw Menu => Solids => Revolve, or by typing REV <Enter> at the Command Line.

The basics of the revolve command are to draw a Closed Polyline outline of one-half of the object in section.

For instance, to create a 3D wine glass you would start by drawing half of the glass in section using a Closed Polyline.

We would then use the Revolve command, define an Axis of Revolution and then define an Angle of Revolution to get our final product.

With the wine glass the Axis of Revolution would be straight through the centerline of the stem and we would use a full 360 degrees for our Angle of Revolution.

Another example for the Revolve command would be a 45 or 90-degree pipe elbow.

We would start by drawing the Circular section of the elbow.

Our Axis of Revolution, or the centerline of the elbow, would be determined by the pipe manufacturers specs.

Our Angle of Revolution would be the same as the degrees of elbow, for instance, 90-degree Angle of Revolution for a 90-degree elbow.

Here is a figure of the circular section showing the circular section and the definition of the Axis of Revolution.

Using an Angle of Revolution of 90 degrees we would generate the following shape.

Other uses of a Revolve command could be a lamp or lamp post, a fancy column, or a pipe with a flanged end.


24

Exercise #8 – Using the Revolve Command 1. Open the drawing file ‘GD33-4L-EX08.dwg’.

Here we see two outlines, one of a basic table lamp and another of a circular section and a centerline for the axis of revolution.

2. Zoom in on the outline of the lamp.


4. Start the Revolve command by selecting the Revolve button on the Solids Toolbar

AutoCAD will prompt you to, Select Objects:

5. Select the Polyline outline of the lamp.

AutoCAD will then prompt you to, Specify start point for axis of revolution or define axis by [Object/X (axis)/Y (axis)]:

6. Using an ENDpoint OSNAP, select the bottom right corner of the outline of the lamp.

7. Using the ENDpoint OSNAP again select the upper right hand corner of the lamp outline.

Note: As with Extrude along a Path, the Revolve command cannot create a self-intersecting solid. It is important to use OSNAPs along our object or to use the POLAR tool to be precise about the Axis of Revolution we define.

AutoCAD will then prompt us to, Specify angle of revolution <360>:

The default value will be 360 for 360 degrees of revolution or rotation.

8. Press <Enter> to accept the default value of <360>.

You will see the object that we have created in this plan view.

9. Use the View Toolbar and switch to an Isometric view and then use the Shade Toolbar and change to a Gouraud Shaded Shademode to see the object in 3D.

This is a basic model. We could however model the lamp stand and the lampshade as separate objects to create a more realistic model.


25

10. Zoom out in the drawing to see the circular section and its pre-defined centerline.

We will use these shapes to create our pipe elbow.

11. Start the Revolve command again.

AutoCAD will prompt you to, Select Objects:

12. Select the Circle object.

AutoCAD will then prompt you to, Specify start point for axis of revolution or define axis by [Object/X (axis)/Y (axis)]:

13. Using an ENDpoint OSNAP, select the end of the line representing the centerline of the elbow.

14. Using the ENDpoint OSNAP again select the other end of the line representing the centerline of the elbow.

AutoCAD will then prompt you to, Specify angle of revolution <360>:

15. Type in 90 at the Command Line and press <Enter>.

The circular shape will Revolve around the specified Axis of Revolution for 90 degrees creating our elbow.

Note: Some basic rules of thumb for the creation of custom shapes:

Only Model what needs to be modeled. The more superfluous detail we add, the larger our drawing file. Later, when we move into the rendering of our model, the longer renderings will take to generate.

If this pipe elbow was to be part of a handrail or a piping process design we wouldn’t need to model the inside diameter unless it was absolutely necessary to the integrity of the design.

With the 3D wine glass at the beginning of this section we may not need to model the inside of the wine glass if it were to be part of a large interior modeling project.

We can keep some parts of our model simple to allow us to add more to objects that need a greater level of detail.


26

Basic Solid Editing The Union Command As we create our more complex models we have some basic tools to edit those 3D solids.

Union allows us to join or basically weld two or more solids into one object.

With the objects in Exercise #4 we could Union the Sphere and the Cylinder to make one object. We could additionally Union the Sphere, Cylinder, and the Box we drew as a base plate.

Sphere and Cylinder model before Union.

Sphere and Cylinder model after Union.

The Union command can be found on the Solids Editing Toolbar.

It can also be found under the Modify Menu => Solids Editing => Union, or by typing UNI at the Command Line and pressing <Enter>.

The Union command is simple. Basically start the command, select the objects that you want to Union, and then right-click or press <Enter>.

Note: The Union command may seem similar to the Block command, allowing us to create one object out of a number of other objects. The difference is that a Block can be edited and re-defined easily. A Union of 3D objects is, for the most part, a one-way operation. It takes much more work to separate or modify the individual solid objects at a later time.


27

Exercise #9 – Using the Union Command. 1. Open the ‘GD33-4L-EX09.dwg’ drawing file.

This is our basic Sphere, Cylinder, Box model from Exercise #4.

2. Confirm that the Solids Editing Toolbar is visible.

3. Start the Union command.

This is the 1st button on the Solids Editing Toolbar.

You can also start the Union command from the Modify Menu => Solids Editing => Union or by typing UNI at the Command Line and pressing <Enter>.

AutoCAD will prompt you to, Select objects:

4. Select the Sphere and Cylinder objects then right-click or press <Enter> to execute the command.

We will see the objects Union together.

5. Start the Union command again.

6. When prompted to Select objects:, select the Sphere/Cylinder object (Note that they now select as one object) and then select the Box or base plate at the bottom.

7. Right-click or press <Enter> to execute the command.

We will now have a union of three objects that react as one object.

You may select the object to verify.

8. Close the ‘GD33-4L-EX09.dwg’ drawing file and chose No when prompted to save changes.


28

The Subtract Command When using AutoCAD 3D modeling tools we will often find it necessary to Subtract one object from another to make a more complex object.

This can be used to simply Subtract four holes from a base plate or, similarly, to Subtract an array of holes along a flange.

We could use it to Subtract the two holes in the basic gasket we modeled in Exercise #6.

The Subtract command can be found on the Solids Editing Toolbar.

It can also be found under the Modify Menu => Solids Editing => Subtract or by typing SU <Enter> at the Command Line.

The syntax or order of operations of the Subtract command is important.

When starting the Subtract command, AutoCAD will prompt you to, SUBTRACT Select solids and regions to subtract from ..

Select objects:

Here we will select the main object that we want to subtract something else FROM.

In the case of the base plate we would select the main base plate object.

AutoCAD will then prompt you to, Select solids and regions to subtract ..

Select objects:

Now we would select the objects we want to subtract from the main object.

Again, in the case of the base plate, we would select the four cylinder objects that represent the boltholes.

The end result would be one object with the four boltholes subtracted out.


29

Exercise #10 – Using the Subtract Command 1. Open the ‘GD33-4L-EX10.dwg’ drawing file.

This is the gasket shape we used for an Extrude example in Exercise #6.

You may Gouraud Shade the object to confirm that the ‘Holes’ are in fact cylindrical solids and have not been subtracted from the main solid.

2. Change back to the 2D Wireframe Shademode to continue the Exercise.

3. Confirm that the Solids Editing Toolbar is visible.

4. Start the Subtract command. This is the 2nd button on the Solids Editing Toolbar.

You can also start the command from the Modify Menu => Solids Editing => Subtract or by typing SU <Enter> at the Command Line.

AutoCAD will prompt you to, SUBTRACT Select solids and regions to subtract from ..

Select objects:

5. Select the main body of the gasket then right-click or press <Enter> to continue with the command.

AutoCAD will then prompt you to, Select solids and regions to subtract.. Select objects:

6. Select the cylinder objects that represent the holes and then right-click or press <Enter> to execute the command.

AutoCAD will Subtract the cylinders from the main object, creating one object and basically punching the holes through that solid.

7. Using the Shade Toolbar, Gouraud Shade the object to see the effect.

8. Close the ‘GD33-4L-EX10.dwg’ and chose No when prompted to save changes.


30

The Rotate3D command In the Exercise #8 we executed a Revolve command to create a basic table lamp model.

However you may have noticed, when switching to an Isometric view, that the lamp was essentially lying on its side.

This would be the same with the example of the 3D wine glass.

The Polyline outline that we use for the wine glass revolve shape is drawn in plan. When it is revolved the wine glass solid is lying on its side in 3-dimensional space.

We can use the Rotate3D command to define an Axis of Rotation and then rotate the objects 90-degrees into a standing position.

We will also utilize this with any number of our models to rotate objects into the positions we need.

The normal AutoCAD rotate command rotates objects in the XY plane around the Z-axis.

Using the Rotate3d command we can define that axis of rotation in any direction.

It is important here to use an OSNAP on our object for the first point of the Axis of Rotation.

Using an OSNAP on the object for the first point of Axis of Rotation

In most cases it is equally important to use our POLAR tool when defining the second point along the Axis of Rotation. This ensures that the model is rotated around a straight vector.

Using the POLAR tool to define the second point along the Axis of Rotation

There is not a Toolbar button for the Rotate3D command, however with basic Toolbar customization, it is easy enough to create a button for that command.

The Rotate3D command can be found under the Modify Menu => 3D Operation => Rotate 3D.

You can also type ROTATE3D <Enter> at the Command Line to execute the command.

Additionally, it is convenient to create an Alias in the Acad.pgp file for the Rotate3D command (i.e. 3DR,*ROTATE3D).


31

Exercise #11 – Using the Rotate3D command 1. Open the drawing file ‘GD33-4L-EX11.dwg’.

This is the revolved model of a basic table lamp we created in Exercise #8 viewed in an Isometric view.

2. Start the Rotate3D command.

This can be found under the Modify Menu => 3D Operation => Rotate 3D or by typing ROTATE3D <Enter> at the Command Line.


3. Select the lamp model and the right-click or press <Enter> to continue with the command.

AutoCAD will then prompt you to, Specify first point on axis or define axis by [Object/Last/View/Xaxis/Yaxis/Zaxis/2points]:

Although there are a number of options, for this exercise we will simply pick two points that represent the Axis of Rotation that we want.

4. Using an OSNAP on the object pick a point for the first point on axis. In my example I have used the CENter OSNAP at the base of the lamp.

AutoCAD will then prompt you to, Specify second point on axis:

5. Using the POLAR tool pick a second point constrained to the right of the object as in the following figure.

This is the centerline, if you will, around which we will rotate the object.

AutoCAD will then prompt you to, Specify rotation angle or [Reference]:

By default, AutoCAD rotates positive degrees in the counterclockwise direction around the defined axis.

6. Type the value 90 at the Command Line and then press <Enter>.

The lamp model is now in a ‘standing’ position.



32

The Align Command As we create our solid objects we can use a combination of the UCS II Toolbar, standard AutoCAD Modify command (e.g. MOVE, COPY, ROTATE) and OSNAPs to position our objects with precision.

Another useful solid editing command we can use to position our objects is the Align command.

The Align command allows us to pick source points on one object and destination points on another object. This then utilizes MOVE, ROTATE, and even SCALE commands in the background to automatically position our objects.

The Align command does not have a Toolbar button, however it can be found under the Modify Menu => 3D Operation => Align or by typing AL <Enter> at the Command Line.

You would start by selecting the first object that you want to Align with a second object, then you would define up to three different source and destination points from the first object to the second object using OSNAPs.

Using a One-point Align, AutoCAD will maintain an objects orientation and simply Move the object based on the source and destination points.

Using a Two-Point Align, AutoCAD will adjust an objects orientation and will additionally ask if you want to scale the object based on the alignment points.

Align can also use a Three-Point adjustment.

Here we have two 3D Models representing two pipes with flanged ends but at different orientations in space. We can easily use the Align command to line up the centers of three boltholes to bring the two models together.

Below (in a Hidden Shademode) we can see the Lines that represent the three selections of source and destination points.

Below is the finished product with both flanges and the boltholes aligned.


33

Exercise #12 – Using the Align Command 1. Open the ‘GD33-4L-EX12.dwg’ drawing file.

This is an arrangement of basic solids.

We will use the Align command to position them together using a Two-point Align then a Three-Point Align.

2. Start the Align command by using the Modify Menu => 3D Operation => Align or by typing AL <Enter> at the Command Line.


3. Select the smaller rectangular solid on the right side then right-click or press <Enter> to continue with the command.

AutoCAD will then prompt you to, Specify first source point:

4. Using the ENDpoint OSNAP select the lower right side corner of the smaller rectangular solid.

AutoCAD will then prompt you to, Specify first destination point:

5. Using the END point OSNAP again select the back corner of the larger rectangular solid.

The first source and destination points should look like this next figure.

AutoCAD will then prompt you to, Select second source point:

6. Using an ENDpoint OSNAP select the upper right hand corner of the smaller rectangular solid.

AutoCAD will prompt you to, Specify second destination point:

7. Using an ENDpoint OSNAP again select the top right corner of the larger rectangular solid.

The second source and destination points should look like the next figure.

AutoCAD will then prompt you to, Specify third source point or <continue>:

8. Right-click or press <Enter> to accept the <continue> default.

AutoCAD will prompt you to, Scale objects based on alignment points? [Yes/No] <N>:

9. Right-click and select Yes or type Y <Enter> at the Command Line.

This will Move, Rotate, and Scale the object into position.


34

10. Start the Align command again.


11. Select the wedge shaped object that is lying on its side.

AutoCAD will then prompt you to, Specify first source point: and then will prompt you to, Specify first destination point: as it did in the previous part of this exercise.

12. Using ENDpoint OSNAPs select the point on the wedge first and then select the corresponding point on the larger rectangular solid as shown in the following figure.

AutoCAD will then prompt you to, Specify second source point: and then will prompt you to, Specify second destination point: as it also did in the previous part of this exercise.

13. Using ENDpoint OSNAPs select the point on the wedge first and then select the corresponding point on the larger rectangular solid as shown in the following figure.

AutoCAD will then prompt you to, Specify third source point: and then will prompt you to, Specify third destination point:

14. Using ENDpoint OSNAPs select the third source and destination points starting with the wedge first and then select the corresponding point on the larger rectangular solid as shown in the following figure.

The adjustment will take place immediately after selecting the last destination point.

Note: The Three-point Align does not use the Scale option.



35

3D Scene Setup 3DOrbit As we work in 3D AutoCAD it is helpful to be able to view our objects from many different Orthographic and Isometric angles.

This is helpful not only when using solids and designing our complex models but also for sharing the visual information.

In Addition to the View Toolbar we can use the 3DOrbit tool to ‘Orbit’ our model, enabling us to view the information from any angle.

The 3DOrbit tool can be found on the 3DOrbit Toolbar.

It can also be found under the View Menu => 3D Orbit or by typing 3DO <Enter> at the Command Line.

I like to use basic toolbar customization to add the 3DOrbit button to my View Toolbar as well.

When the 3DOrbit tool is launched you will see a slight change in the drawing area as well as with the AutoCAD crosshairs.

In the drawing area you will see the ‘Arcball’, which is a circle divided into four quadrants by smaller circles.

Depending on the crosshairs location in reference to that circle the cursor will also change appearance.


36

To use the 3DOrbit you simply press and drag to change your viewing angle of the model.

If you press and drag while the cursor is inside the circle it will perform a free orbit.

Pressing and dragging from outside the circle will rotate the view around an imaginary Z-axis projecting straight out from the screen.

If you place the cursor inside one of the four smaller circles then press and drag the view will rotate around imaginary X and Y-axes respectively.

3DOrbit offers a number of options through the right-click shortcut menu as well.

We can choose some basic options such as Pan and Zoom.

We can access the More option to use Zoom Window, Zoom Extents, or to change Front and Back clipping planes among other tools.

Also in the More menu is one of my favorites, Continuous Orbit.

The Projection option offers Parallel and Perspective views.

A Parallel View is a 3D view where all lines in the respective planes are parallel to each other. The Perspective view creates an invisible vanishing point in the distance giving our models more depth or a more realistic look.

We can also access our Shading Modes and Preset Views (Orthographic and Isometric).

These tools give us the ability to work with our 3D objects or present the 3D model information in a number of different manners.


37

Exercise #13 – Using 3DOrbit 1. Open the ‘GD33-4L-EX13.dwg’ drawing file.

This is a basic arrangement of solid primitives.

2. Start the 3DOrbit command.

This can be found on the 3DOrbit Toolbar.

The 3DOrbit command can also be started from the View Menu => 3DOrbit or by typing 3DO <Enter> at the Command Line.

You will see the green ‘Arcball’ displayed in the center of the drawing area.

Note that the AutoCAD crosshairs change to a different cursor shape.

3. Place the cursor inside the Arcball.

The cursor will look like a small sphere encircled by two ellipses.

4. Press and hold the left mouse button and ‘Drag’ to see the model rotate freely in space.

5. Place the cursor outside of the Arcball.

The cursor will change to a circular arrow.

6. Click and drag with the left mouse button and note that the model objects rotate around an imaginary Z-axis which essentially comes straight out from the center of the screen..

This can also be called a ‘Roll’

7. Place the cursor inside one of the smaller circles on the left or right side of the Arcball.

The cursor will change to a horizontal ellipse.

8. Click and drag to see the model objects rotate around the vertical axis.

9. Place the cursor inside one of the smaller circles at the top or bottom of the Arcball.

10. Click and drag to see the model objects rotate around the horizontal axis.

11. Right-click anywhere in the drawing area.

Note the different options within the shortcut menu.

12. Select the Reset View option.

The view will return to the initial view that we started in.


38

13. Right-click in the drawing area again.

14. Select the Shading Modes => Gouraud Shaded option.

Note the same appearance as the shade modes available from the Shade Toolbar

15. Right-click again in the drawing area and select the Projection => Perspective option.

The display of the objects will change to a Perspective display giving the objects more depth.

Note: You can exit out of the 3DOrbit command at anytime by Pressing ESC or ENTER to exit, or right-clicking to display shortcut-menu (which is shown at the command line while the command is running).

If you exit out of the 3DOrbit while in perspective mode, AutoCAD will not let you execute most normal commands. Instead you will see a message returned at the Command Line that says; You cannot point within a Perspective view. Change the Projection to Parallel from the 3D Orbit right-click menu.

You can also select a View option from the View Toolbar to exit the Perspective View.

16. Right-click again in the drawing area.

17. Select the More => Continuous Orbit option.

18. Click and drag and then let go of the left mouse button.

Note that the model objects now spin in a continuous motion.

You can adjust the continuous orbit by clicking and dragging in different directions at different rates of speed.

This is not very useful…But it is kind of fun ☺

You are still able to right-click to access the 3DOrbit options.

19. Choose Orbit from the shortcut menu to go back to the normal 3DOrbit command.

There are a number of other options in the 3DOrbit shortcut menu that you can experiment with.

Remember to use the AutoCAD Help Menu to find out more specifics about each option.

20. Press Esc or Enter to exit the 3DOrbit command.



39

Named Views We can use the 3DOrbit command to create many unique views of our models.

However we will most likely have to return to our Orthographic views to perform other functions.

The 3DOrbit views are not retained.

We can save our 3DOrbit views using the Named Views dialog.

For instance this will allow you to set up a Perspective view and then save that view. You could then return to a Parallel view (SW Isometric for example) to work on the model. You can then restore the Perspective view when desired.

Named Views can be found on the View Toolbar

Named Views can also be found under the View Menu => Named Views or by typing V <Enter> at the command line.

After setting up your view with 3DOrbit launch the Named Views dialog. Click the New button in the dialog then type in a name for the view in the View Name field and then click OK.

You can then restore the view later by launching the Named View dialog, selecting a saved view and then clicking the Set Current button.

Select the New Button to name and save a view

Select a View in the list and then click Set Current to restore that view


40

Extras AutoCAD System Variables that Affect 3D Operations The following is a short list of some System Variables that have some affect on 3D Operations

The definitions of the variables are taken from the AutoCAD Help Menu

DISPSILH - Controls display of silhouette curves of solid objects in Wireframe mode. Also controls whether mesh is drawn or suppressed when a solid object is hidden.

0 Off

1 On

FACETRATIO - Controls the aspect ratio of faceting for cylindrical and conic ShapeManager solids. A setting of 1 increases the density of the mesh to improve the quality of rendered and shaded models.

FACETRES - Adjusts the smoothness of shaded and rendered objects and objects with hidden lines removed. Valid values are from 0.01 to 10.0.

HIDEPRECISION - Controls the accuracy of hides and shades. Hides can be calculated in double precision or single precision. Setting HIDEPRECISION to 1 produces more accurate hides by using double precision, but this setting also uses more memory and can affect performance, especially when hiding solids.

HLSETTINGS - Sets the display properties of hidden lines. These settings are visible only when the HIDE command or the Hidden option of the SHADEMODE command is used.

HIDETEXT - Specifies whether text objects created by the TEXT, DTEXT, or MTEXT commands are processed during a HIDE command.

Summary This is a basic and, of course, brief look at the beginnings of creating Solids and performing some simple editing on those Solids. There are numerous other tools that one can use to increase their efficiency in creation and editing time.

The Solids Toolbar offers other creation methods such as Slice, Section, and Interfere. It also has the Solview and Soldraw commands for setting up layouts to get the model ready for output.

The Solids Editing Toolbar has numerous editing tools including Extrude, Move, and Offset Faces.

It has tools to Taper and Rotate faces as well as color individual lines or faces in a solid.

The normal AutoCAD Fillet and Chamfer commands can be used to edit solids as well.

There are the Vertical Applications that Autodesk offers, such as Land Desktop and Architectural Desktop that work in 3D environments as a matter of course. Using normal AutoCAD Solids we can model the special items we need that complete the entire project and make the most of the information we have already developed.

3D allows us to visualize and communicate our designs easier and with a greater impact.

We live in a 3D world after all.

Thank you all very much for attending and have a great AU 2005 experience.

Alex Wood WGM Group, Inc. - CAD Training Solutions, LLC [email protected] - [email protected]

it's a 3d world after all · the view toolbar gives us tools to quickly switch to any of our...

Documents