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Subtracting two 3D objects

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Hi

I am working on a geometry that consists of an impeller in a cylindrical tank. The impeller is imported as an stl. Then, in Comsol, I build a cylinder surrounding the impeller. I then want to subtract the impeller from the cylinder, but when I try to do this, both objects dissappear.

I am using version 4.1.0.185, CFD module.

Thank you!
Sylvana

3 Replies Last Post Mar 26, 2011, 7:49 p.m. EDT
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago Mar 24, 2011, 4:34 p.m. EDT
Hi

that is probably because the stl geometry has not been convertd correctly to a comsol "object", there are a few settings available, either to transform an imported geometry to a COMSOL "object" (somewhere there in the right click options), or to force COMSOL to use a given external geometrial solver (i.e. Parasolid if you have the option)

--
Good luck
Ivar
Hi that is probably because the stl geometry has not been convertd correctly to a comsol "object", there are a few settings available, either to transform an imported geometry to a COMSOL "object" (somewhere there in the right click options), or to force COMSOL to use a given external geometrial solver (i.e. Parasolid if you have the option) -- Good luck Ivar

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Posted: 1 decade ago Mar 25, 2011, 10:43 a.m. EDT
Hi, Ivar

Thank you very much for your response. I tried "convert to solid" in the Geometry right-click options, but the same happens. I honestly don't know where to indicate the Parasolid option. I don't have the CAD Import Module, I don't know if the Parasolid option only works with this module. Anything else I can do? I tried to subtract the impeller from a square and I get a message saying "internal geometry error".


Thank you

Sylvana
Hi, Ivar Thank you very much for your response. I tried "convert to solid" in the Geometry right-click options, but the same happens. I honestly don't know where to indicate the Parasolid option. I don't have the CAD Import Module, I don't know if the Parasolid option only works with this module. Anything else I can do? I tried to subtract the impeller from a square and I get a message saying "internal geometry error". Thank you Sylvana

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Posted: 1 decade ago Mar 26, 2011, 7:49 p.m. EDT
Hi

I just created the geometry from scratch in Comsol, which was very easy. However, this was a simple geometry. It would still be nice to know what went on in my import process for future more complex geometries.

Any ideas are welcome!
Thanks!

Sylvana
Hi I just created the geometry from scratch in Comsol, which was very easy. However, this was a simple geometry. It would still be nice to know what went on in my import process for future more complex geometries. Any ideas are welcome! Thanks! Sylvana

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