How to get solid model from IGES/Step trimmed face import

Some CAD system exports a solid model with trimmed faces in IGES/STEP format. In IGES it's entity 402 with format 7. Thus a TopoDS_Compound is created in OCC. Since this TopoDS_Compound is a collection of different types of TopoDS_Shape, so the trimmed faces are actually transfered into TopoDS_Faces and no solid model is created.

In a previous topic (around two years ago) Rob Bachrach wrote that " I use the OneShape function to get it as a single shape. This usually gives me a single solid or a compound of solids". It's good idea. However it seems it doesn't work in current 6.2 version.

Does anyone have any clue or experience on how to get solid model from this iges/step faces import?



Rob Bachrach's picture

In that previous topic, I was referring to the STEP import. Most CAD systems are much more likely to write full solid model geometry in STEP files than in IGES.

If you look in the OCC IGES User's Guide, you will see that the only way to get a TopoDS_Solid is in response to an entity 186 (ManifoldSolid) in the IGES file. If you are looking to join faces together to form solids, you may need to do some sewing.