Hi Val, yeah that definitely sounds like normals not coming through - when normals do come through even pretty rough meshes get shaded nicely with the shading actually matching the shape of the original NURBS surface, since the vertex normals are actually the normals from the original generating NURBS surface.

If you see some of the polygon structure revealed in the shading then yup that's usually a sign that the normals are not coming through.

Getting the proper vertex normals over does usually make a very significant difference in shading quality.

When the normals do not come over in the import they will instead be created by the renderer by just averaging the face normals of all the faces that surround each vertex. That can work ok if all the faces are of relatively uniform size and distribution, but often times that kind of polygon distribution goes with sub-d meshes and not CAD generated meshes which tend to have things like big flat areas next to curved filleted areas.

If you use "Divide larger than" to dice up your output polygons to try to get them into that kind of even distribution and same size that can help to make "cooked up by face averaging" normals to look better, but even then it's still just so much better to have the proper normals.

- Michael