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It is likely there are too many vertices in collision geometry

asked 2016-11-03 22:41:26 -0500

clark_txh gravatar image

when I run move_goup , I get a warning message that It is likely there are too many vertices in collision geometry.

what is mean about this?

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answered 2016-11-04 02:56:54 -0500

gvdhoorn gravatar image

This was a warning that was recently added to MoveIt that tells you that the meshes (*.stl, *.dae or something else) that you configured your urdf model to use (in your <geometry><mesh filename="..">...</geometry> tags) are probably (way) to detailed (have too high a face and / or vertex count).

If those are too detailed, collision checking will become slow, but the results will not necessarily be significantly better.

People typically create special collision meshes by creating convex hulls. If that is not possible (because of holes in your geometry that need to be preserved), creating a subsampled version of your meshes is a good way to do this.

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Wouldn't alpha shapes work a lot better?

NEngelhard gravatar image NEngelhard  ( 2016-11-04 04:41:38 -0500 )edit
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There are many more ways to generate proper collision geometry (convex decomposition, bounding meshes, etc). I just wanted to give an example

The important point is that you shouldn't be using detailed meshes for collision checking purposes (or at least: not too detailed meshes).

gvdhoorn gravatar image gvdhoorn  ( 2016-11-04 04:59:50 -0500 )edit
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answered 2022-03-25 03:46:55 -0500

updated 2022-03-25 03:47:06 -0500

The thing which worked for me was using the Decimate Modifier in Blender to reduce vertices.

I personally used the Collapse function to reduce the vertices depending upon a ratio instead of Un-Subdivide as it saturates after subsequent iterations.

References:

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Asked: 2016-11-03 22:41:26 -0500

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Last updated: Mar 25 '22