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AutoCAD Tutorial

AutoCAD 3D Modeling: Mass Properties

September 23, 2003

Solid models consist of some valuable information. To extract such information we use MASSPROP. The command is one of inquiry tools. It is also applicable for regions. You can invoke this command by clicking its button on Inquiry toolbar [Figure 1]. The following tutorial shows you what would be the result of MASSPROP for a typical region and solid model.


Figure 1

Notes:

  • This tutorial is designed for AutoCAD 2004 though might be applicable to other releases.
  • In this tutorial user entries are in boldface.
  • The 8 symbol represents pressing Enter.

1. Download and then open r16_mass_properties.dwg. The file consists of a solid model and a region [Figure 2].

Note: If you are using AutoCAD 2002 or an earlier release download r15_mass_properties.dwg.


Figure 2

2. To generate a better view alter the FACETRES system variable to 10:

Command: facetres 8
Enter new value for FACETRES <0.5000>: 10 8

Note: FACETRES accepts values from 0.01 to 10. The bigger values generate better views. The value assigned to this system variable has no effect on the result of MASSPROP.

3. Regenerate the drawing [Figure 3].


Figure 3

4. Invoke MASSPROP (Tools menu > Inquiry > Region/Mass Properties).

5. Click the region. Some information appears in Text window [Figure 4].


Figure 4

6. As you see the area, perimeter, bounding box, and centroid of the region are reported. Type N and then press Enter to avoid writing the results to a file.

7. Invoke MASSPROP, select the solid and then press Enter to view the complete report in Text window [Figure 5].


Figure 5 - Click on image to enlarge

8. Mass, volume, bounding box, centroid, moments of inertia, products of inertia, radii of gyration, and principal moments of the solid are reported. Type N and then press Enter to save the report. A dialog box appears [Figure 6].


Figure 6 - Click on image to enlarge

9. Save the report as "sample mass prop report". The file name extension would be MPR. You can open this file with Notepad or any other text editor [Figure 7].


Figure 7 - 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, and an instructor for AUGI Training Program. He has written 8 books in Farsi, 3 booklets in English, and more than 100 articles for different magazines and newsletters. You can reach Alireza at alireza.parsai@cadpanel.com or visit his website www.cadpanel.com .  

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