Hi Michael T - even with the best hardware available, that process of converting every single polygon in a dense mesh into a trimmed plane in a NURBS solid is going to very easily have problems.

It's a fundamental mis-match between how things are designed. With polygons, it is intended that curved surfaces are approximated with a whole lot of little facets. With NURBS it is intended that curved surfaces are represented by large smooth spline surfaces.

You shouldn't try to make a polygon mesh model using only 1 polygon for what is supposed to be a curved surface, and you shouldn't try to make a NURBS model using a zillion little facets for what is supposed to be 1 curved surface.

In some simple cases you may be able to force the issue, but you should not expect for it to work well in general, it's not using the different structures in the way that they are intended to be used.

- Michael