home - about - advertise     

AutoCAD Tutorial

AutoCAD 3D Modeling: 3D Modifying Commands

August 11, 2003

The following tutorial shows you how to create 3D Arrays, rotate objects about 3D axes, and mirror objects with respect to any plane in 3D space. Although you can use ARRAY, ROTATE, and MIRROR commands in 3D space they are limited to the current XY plane. However there are 3D equivalents of these commands that save your time and extend your abilities.


  • 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 r16_3d_modify.dwg.

Note: If you are using AutoCAD 2002 or an earlier release download r15_3d_modify.dwg

2. Open the drawing in AutoCAD. The drawing consists of 2 solid models and some lines shown in 3 viewports [Figure 1].

Figure 1 - Click on image to enlarge

Note: For more information on viewports read the following tutorial:
AutoCAD 3D Modeling: Tiled Viewports

3. Make sure that the left viewport is enabled.

4. Select the cone and then invoke MIRROR3D (Modify menu > 3D Operation > Mirror 3D).

5. Answer to the prompts:

Specify first point of mirror plane (3 points) or
[Object/Last/Zaxis/View/XY/YZ/ZX/3points] <3points>: xy8
Specify point on XY plane <0,0,0>: 0,0,18
Delete source objects? [Yes/No] <N>: y8

Note: The cone is mirrored with respect to a plane that is parallel to XY plane and passes through 0,0,1 [Figure 2].

Figure 2

6. Rotate the cone about Y axis with ROTATE3D (Modify menu > 3D Operation > Rotate 3D):

Command: rotate3d8
Current positive angle: ANGDIR=counterclockwise ANGBASE=0
Select objects: p8
1 found
Select objects:8
Specify first point on axis or define axis by
[Object/Last/View/Xaxis/Yaxis/Zaxis/2points]: y8
Specify a point on the Y axis <0,0,0>:8
Specify rotation angle or [Reference]: 608

Note: The cone is rotated 60 degrees with respect to the Y axis [Figure 3].

Figure 3 - Click on image to enlarge

7. On the viewport to the left switch to 2D Wireframe shade mode.

8. Move the cone to the midpoint of the lower line on the slope [Figure 4].

Figure 4 - Click on image to enlarge

9. Create a polar array of the cone about the perpendicular line to the slope. Use 3DARRAY (Modify menu > 3D Operation > 3D Array):

Command: _3darray
Initializing... 3DARRAY loaded.
Select objects: p8
1 found
Select objects:8
Enter the type of array [Rectangular/Polar] <R>:p8
Enter the number of items in the array: 48
Specify the angle to fill (+=ccw, -=cw) <360>:8
Rotate arrayed objects? [Yes/No] <Y>:8
Specify center point of array: int of
Specify second point on axis of rotation: end of

10. Switch to Gouraud shade mode in all viewports. Freeze layer 0 [Figure 5].

Figure 5
- Click on image to enlarge

About the Author

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

More CAD Corner tutorials >>

CADdigest Weekly
Email (required) *

A week's worth of articles will be emailed to you. See latest issue .