AutoCAD 2007/2008/2009

AutoCAD 2007/2008/2009

Distinguished Contributor
Posts: 205
Registered: ‎02-24-2009
Message 1 of 5 (14,314 Views)

Moment of inertia?

14314 Views, 4 Replies
07-30-2010 06:31 AM


I would like to find a way in AutoCAD to calculate the (momet of inertia). In the (help) of AutoCAD exists (moment of inertia) but when I opened it, I foud nothing about (moment of inertia) but only about calculation of the area.

Is there anybody can help me to find a way to do that? Specially, that can be useful in the irregular shapes.



Valued Mentor
Posts: 1,257
Registered: ‎08-17-2007
Message 2 of 5 (14,309 Views)

Re: Moment of inertia?

07-30-2010 08:04 AM in reply to: jz4all
Posts: 16
Registered: ‎03-25-2009
Message 3 of 5 (14,287 Views)

Re: Moment of inertia?

08-01-2010 02:03 AM in reply to: jz4all



once you have created your shape from lines and arcs you will need to create a region from the shape by using the "region" command and selecting all the lines and or arcs after I usually move the bottom left corner of the shape to 0,0. Once you have done this, run the "massprop" command and click the region you created, you will then have a text box that pops up showing the moment of inertia results.


See attached image example.


Hope this helps :smileyhappy:
Distinguished Contributor
Posts: 205
Registered: ‎02-24-2009
Message 4 of 5 (14,274 Views)

Re: Moment of inertia?

08-02-2010 12:07 AM in reply to: jz4all

Thankyou for help.It works fantastic.

New Member
Posts: 1
Registered: ‎02-15-2013
Message 5 of 5 (10,385 Views)

Re: Moment of inertia?

02-15-2013 10:04 PM in reply to: jz4all

What is I & J in below result




rea:                    1437.9615
Perimeter:               491.3206
Bounding box:         X: -96.7383  --  -31.7383
                      Y: 438.3598  --  583.3598
Centroid:             X: -62.7098
                      Y: 517.4386
Moments of inertia:   X: 387984772.1991
                      Y: 5941776.0140
Product of inertia:  XY: -46145896.8066
Radii of gyration:    X: 519.4380
                      Y: 64.2813
Principal moments and X-Y directions about centroid:
                      I: 192305.5258 along [0.1812 0.9834]
                      J: 3075742.0965 along [-0.9834 0.1812]




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