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Tesselate and/or split 3D drawing into (solid primitive) prisms


New member
I have .step 3D drawings made in Catia that I need to pass to an analysis program. The original drawing in CAD has complex ("shape") parts and curves that need to be simplified for analysis. If necessary, the original drawing can also be saved in other formats such as .stl and .igs.

The analysis program only works with 3D drawings composed of solid primitives: cubes, planes, cylinders, cakes, cones, spheres, prisms, torii, elliptic cylinders and trapezoids. It can read only the following file formats: step, iges,
gdml, sysbas, geant4, and its own format, fastrad.

I need a way to "model" complex CAD drawings out of the above solid primitives only, and I think tesselation is a sensible option (giving, if necessary, the tesselation triangles some thickness to make them into prisms). However, tesselation usually results in a single CAD object, whereas I would need to properly split the tesselated object into individual prisms for my analysis program to understand.

Are there methods/3rd party programs that can achieve what I need? Tesselation seems like a brute-force method if there exists a better way to approximate a model into solid primitives, but is a fine solution as long as I can end up with a drawing made of prisms.

The key point is that I need the constituent solids that make up the 3D drawing to each be unique elements, so that my analysis software can read the file.


Super Moderator
What you are describing, Alexlj, is called "FEM" (Finite Element Modeling). CATIA has a FEM workbench that will quickly and easily create a "mesh" (sub-divide your model into a network of 3D triangles and/or cubes). You can use the CATIA FEA analysis workbench, or output the mesh file in a neutral format to use with another solver.
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New member
Thanks for your reply. I am playing around with CATIA's FEA but I can't figure out how to export the mesh, unless the case is that I can only export as .CATAnalysis or .cgr. Is it possible to export as a more amenable format or should I try another FEM tool?


New member
Actually since Fastrad cannot do tetrahedrons I need to use something else, as I don't think I can do prisms (triangles with a thickness) in CATIA. Something as crude as regular cubes instead of tetrahedrons would be good enough.