AutoCAD 3D Modeling: Managing Regions
August 13, 2003
Although regions are similar to flat surfaces
you can use some of 3D solids commands to modify them. The
following tutorial shows you how to use Boolean commands to
create a complex region. You will also use the MASSPROP command
to extract some useful data from the region.
If you are using AutoCAD 2002 or an earlier release download
2. Open the drawing
in AutoCAD. The drawing consists of some regions [Figure 1].
3. Invoke INTERSECT
(Modify menu > Solids Editing > Intersect). This Boolean
operation creates a region based on the common/overlapping area
of selected regions. The command erases the original regions.
4. Select the two
top segments. A new region is created [Figure 2].
5. Invoke UNION
(Modify menu > Solids Editing > Union). The UNION command
creates a region by joining selected ones. The original regions
will be removed.
6. Select the top
region and the big one. The regions will union [Figure 3].
7. Invoke SUBTRACT
(Modify menu > Solids Editing > Subtract). Here you will select
two groups of regions. The second group will be subtracted from
the first one to create a new region. This Boolean command will
also delete the original regions.
8. Select the big
region as the first group and then press Enter.
9. Select the
circular regions as the second group and then press Enter to
create the final region.
10. Alter the shade
mode to Gouraud shaded [Figure 4].
11. Invoke MASSPROP
(Tools menu > Inquiry > Region/Mass Properties).
12. Select the
region. Some useful information appears on Text window [Figure
5]. Press Enter to exit the command.
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
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