Controlling step export to avoid degenerate toroids

erik_knudsen

A bit of a longshot: For my downstream use I export parts and assemblies to step-files for further processing. One problem however is that downstream applications have a  problem with degenerate toroidal surfaces. In our field these kind of geometries tend to be "not uncommon". I have found that other CAD-tools (such as FreeCAD) avoid this step-construction and instead generate an equivalent spline generated surface. A spline works fine downstream, whereas the degenerate toroids do not. I've tried the different available versions of the step-format but in this respect onshape step export works the same. Is there a way with which one could exercise control on how geomettr is exported in the onshape step export?

GregBrown

Have you tried some of the “preprocessing” options available with STEP export. I have seen the “basic” and “advanced” options will transfer more cleanly (avoiding the issues with incorrectly trimmed toroids) 

erik_knudsen

Thank you for pointing me in that direction - I'm still experimenting but the initial tests seem to work. Strangely enough, from inspecting the generated step-files in a couple of simple test-examples, it looks like the basic and advanced options create not one, but two degenerate toroidals.