Centroid same as Center of Gravity?
Centroid same as Center of Gravity?
(OP)
I have a 3D model in Autocad Mechanical 6.0 and I need to find the center of gravity. It is an assembly drawing, meaning different solids used in one drawing that I created. If I unioned all the parts to make one solid, could I find by using the mass properties? Is the centroid the same as the center of gravity? I have other seats in CAD software, if someone knows a to figure it. The seats include: Mechanical Desktop 5.0, Autocad 2002, Solid Works 2001+, Solid Edge, TurboCad 9.0 Pro and CoCreate's One Space Designer 11.0 and 11.6
Any help would be nice. Thanks.
Any help would be nice. Thanks.





RE: Centroid same as Center of Gravity?
Using ACAD, you can create a composite solid and determine its mass properties which will include the x,y,z coordinates of its center of mass.
You can also determine the center of mass of an assembly in Solid Edge. I'd have to think SW and MDT permit it as well.
Have you tried it an are viewing the answers as suspect?
RE: Centroid same as Center of Gravity?
RE: Centroid same as Center of Gravity?
Is your composite assy something whose centroid you could numerically estimate, at least in one plane?
Another thing: In "vanilla" ACAD, all bodies have the same density so different materials all get treated the same. The could give seriously erroneous results.
I just used ACAD 2k2 and it correctly determined the centroid of 2 cubes spread 4" apart and also when I added a 3rd cube stacked on top of one of the originals. I did not need to "union" them into a single solid.
Be sure to realize that the centroid coordinates will be with respect to whereever the origin happens to be set.
RE: Centroid same as Center of Gravity?
RE: Centroid same as Center of Gravity?
RE: Centroid same as Center of Gravity?
1. Where your CG is referenced to, i.e. coordinate system reference. I place the UCS somewhere that is a good reference and then make sure you reference the UCS instead of the WCS.
2. Make sure all of your parts have the material properties specified. I can't remember what MD does, but it assigns some default material properties if you don't.
3. Make sure you select all parts that make up the assembly when you start the mass properties.
I just did a quick and dirty assembly of 3 parts and did the mass properties to find the CG and it worked perfectly.
RE: Centroid same as Center of Gravity?
RE: Centroid same as Center of Gravity?
Pick your assembly(ies),
Use the dialogue box to set your units, set your co-ordinate system to either UCS or WCS, and set all your component materials and properties.
Go to the results tab and press Calculate.
This should give you everything you need to know. Also you can switch back to the setup tab and change materials etc and re-calculate straightaway.
Hope this helps...
RE: Centroid same as Center of Gravity?
In any case, for an assy of components of the same density, the centroid given by Acad is the same as the CoG.
RE: Centroid same as Center of Gravity?