Hi, I apologize in advance if this is not the right place for bug issues.
The b-rep created by BRepBuilderAPI_NurbsConvert for the "linkrods.step" example appears to lose the orientation of reversed input faces, resulting both in visually incorrect surface normals, and a failure in BRepAlgo::IsValid().
To reproduce, use STEPControl_Reader to load the part, BRepBuilderAPI_NurbsConvert(shape) to do the conversion, and BRepAlgo::IsValid() to check the result. Note that the "Copy" parameter to BRepBuildAPI_NurbsConvert does not correct the error.
If someone has experienced this problem and has a workaround (or patch), please let me know.