Center of Mass

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mc_axe
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Joined: 12 Mar 2013, 18:44

Center of Mass

Post by mc_axe » 01 Dec 2018, 19:39

Hello evryone, anyone knows if we already have a tool to calculate center of mass for a closed mesh for example a rock ( assuming uniform density - same material everywhere) ?

Transform > 'Move center to vertices' preety much averages the possitions of vertices, so it depends on the topology,
A ball that has its top part subdivided a few times will have a center close to the top, while real center of mass should remain pretty mcuh in the same place.

I tried also rigid bodies where there is inertal properties > center of mass, but is litterally the same algorithm.

Here is a response that i found on google groups:
To find the center of gravity (or "centroid") of a polygonal mesh:
convert all of its faces to triangles, and average the centroids of
all of the triangles, weighted by the doubled area of each face.
Wikipedia calls it <a href="http://en.wikipedia.org/wiki/
Centroid#Centroid_by_geometric_decomposition">Centroid by Geometric
Decomposition</a>.

C = Centroid <vector>, A = (area of a face * 2)
R = face centroid = average of vertices making the face <vector>
C = [sum of all (A*R)] / [sum of all R]
Thx