AutoCAD 3D Modeling: Trim and Extend
July 31, 2003
The TRIM and EXTEND commands are not only used in 2D drawings
but also applicable to Wireframe models. In this tutorial you
will draw a 3D polyline and use TRIM and EXTEND in 3D space.
If you are not familiar with Wireframe models, read the
following tutorials.
► AutoCAD 3D Modeling:
Wireframe Models, Part 1
► AutoCAD 3D Modeling:
Wireframe Models, Part 2
► AutoCAD 3D Modeling:
Wireframe Models, Part 3
Notes:
- This tutorial is designed for AutoCAD 2004 though might be
applicable for other releases.
- In this tutorial user entries are in boldface.
- The
8
symbol represents pressing Enter.
1. Download the
following files:
►
r16_trim_extend.dwg
► SPIRAL.VLX
Note:
If you are using AutoCAD 2002 or an earlier release download:
►
r15_trim_extend.dwg
► SPIRAL.VLX
2. Open the drawing
in AutoCAD.
3. Load SPIRAL.VLX.
Note:
To learn how to load an application into AutoCAD read the
following article:
► Loading Applications into
AutoCAD 2002
4. Invoke SPIRAL.
5. Set the values
as shown in Figure 1. Make sure to deselect Solid Model option.
Figure 1
6. Click OK. A 3D
polyline will be created [Figure 2].
Figure 2
7. Change the view
to SE Isometric [Figure 3].
Note:
To learn more on 3D views read the following tutorial:
► AutoCAD 3D Modeling: 3D Views
Figure 3
8. Draw a line
along Z axis. The start point of the line is origin and the
length is equal to 30 units [Figure 4].
Figure 4
9. Invoke EXTEND.
10. Select 3D
polyline as the boundary edge, and then press Enter to exit the
boundary edge selection mode.
11. Click the top
end of the line to extend. The line will not be extended as it
really does not intersect with the polyline.
12. Select the Project option and set the projection mode to
View:
Select object to extend or
shift-select to trim or [Project/Edge/Undo]:
p8
Enter a projection option [None/Ucs/View] <None>:
v8
13. Now click the top end of the line to extend it [Figure
5].
Figure 5
14. While pressing Shift key click on the bottom end of the
line to trim it [Figure 6].
Figure 6
15. Press Enter to exit the command.
16. Change the view. As shown in figure 7 the
boundary/cutting edge was only valid in the previous view.
Figure 7
Alireza Parsai is the founder of cadpanel.com. He is a
mechanical engineer with more than 12 years experience with
AutoCAD. Alireza is an Autodesk Authorized Author, the AutoCAD
consultant for Al Khawarizmi Institute, a contributing editor
for Augiworld magazine, a writer for CAD Digest, an instructor
for AUGI Training Program, and an elected speaker for Autodesk
University 2002. He has written 7 books in Farsi, 3 booklets in
English, and more than 30 articles for different magazines and
newsletters. You can reach him at
alireza.parsai@cadpanel.com or visit his website
www.cadpanel.com.
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