ToNURBS of toroidal RevSurface creates invalid brep

_ToNURBS on the brep in ToNURBS_creates_InvalidBrep.3dm (36.3 KB) will create an invalid brep.

I guess this may be related to RhinoCommon’s Surface.ToNurbsSurface returning 2 for the accuracy parameter when the underlying RevSurface is passed to it.

https://developer.rhino3d.com/api/RhinoCommon/html/M_Rhino_Geometry_Surface_ToNurbsSurface_1.htm

Hi @spb,

Thanks for reporting. I’ve logged the issue:

https://mcneel.myjetbrains.com/youtrack/issue/RH-57922

Did you make this model in Rhino? Why the tight tolerance?

Thanks,

– Dale

It was imported from a STEP file. The units are inches, so the 0.0004 tolerance is about 0.01 mm.