The other possibility to generate a regular grid would be to do it directly from the NURBS surface.

This would mean instead of reading the .obj file, you would use the OpenNURBS toolkit to read the NURBS surface data from the .3dm file directly, and then evaluate uv points on the NURBS surface.

The procedure I describe above is basically an approximation of evaluating the NURBS surface, using the triangulated data instead of using the surface directly.

- Michael