Hi Steve,

> Carrara (and some other apps) will give option on import for smoothing

Yeah, but in that case the smooth vertex normal will be created by averaging polygons that surround a vertex. This will only be an approximation of the true normal from the original NURBS object, and there are frequently problems with this kind of approximation in areas where there are polygons of different sizes adjacent to one another. Things like a small sized polygon will tend to have an undue weight applied to the averaging and have a visible shading effect on the larger polygon.

These problems are eliminated when you can carry the original vertex normals from the precise NURBS model to be used for the final shading.

OBJ is able to contain these normals, so that's why you can avoid many potential shading difficulties if you use OBJ format instead of 3DS, since 3DS has no facility within it to store the vertex normal information.

This all depends on your program reading the normals in from the OBJ file of course, there are some programs like Max which skip them. But I believe that Poser will use them if present.

Some programs will only use them if you turn MoI's welding option off, since some programs expect to have one normal per vertex, instead of being able to have faces that share one 3d point but have unique normals per face which is what happens if you have welding turned on. So that's why for maximum compatibility it is not bad to turn welding off for this, I probably should switch that to be off by default instead of on by default.

- Michael