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Difference operation: All objects vanish

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Hi, I have a problem. When I try to use difference on two groups of spheres all involved spheres vanish. I used union on both groups before the difference operation is applied to them and the result stayed the same. When I use the difference on only few of the spheres, especially if it is never the case that two spheres touch the same sphere that should be subtracted, everything works well.

I attached the file to this posting.


1 Reply Last Post Jan 9, 2012, 7:12 a.m. EST
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago Jan 9, 2012, 7:12 a.m. EST
Hi

Indeed COMSOL seems to have problems with boolean differences of several intersecting spheres. I would suggest that you send this example to support I do not believe we users can propose anything much better.

I mostly use an external CAD programme for my geometry, particularly for complex ones, and spheres, like torus are "complex" topologies, COMSOL is first of all a FEM tool, not really a CAD tool ;)

By the way, you have also the Transformation Array operation (or copy with a set {} of coordinates) for your sphere generation

--
Good luck
Ivar
Hi Indeed COMSOL seems to have problems with boolean differences of several intersecting spheres. I would suggest that you send this example to support I do not believe we users can propose anything much better. I mostly use an external CAD programme for my geometry, particularly for complex ones, and spheres, like torus are "complex" topologies, COMSOL is first of all a FEM tool, not really a CAD tool ;) By the way, you have also the Transformation Array operation (or copy with a set {} of coordinates) for your sphere generation -- Good luck Ivar

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