Hi Steve (STEVE_HOME),

> The problems with smoothing of exported meshes from
> "nurbs surface->mesh" exporters is due to the bad topology,
> mainly around the boundary's of joined curved surfaces.

It's not quite so simple as "bad topology" - doing shading by automatically creating vertex normals is sensitive to many kinds of topologies like just a big polygon next to some small ones.

You get easily get shading glitches with models purely created within the polygon environment with smoothing groups and break angles unless you have very regularly sized and distributed polygons. That's not just "good topology", it's kind of "restricted topology".


> mainly around the boundary's of joined curved surfaces

Yeah, it's also due to issues like a change in shape happening at the boundaries as well.


> If you export a sphere from MOI then render it with
> vertex normal info or with smoothing, then you would
> have to guess which was which, as there is no difference
> due to poly flow

If you had something that was only one portion of it as a sphere and then it transitions to some other shape adjacent to it, like a fillet or something like that, that's when you won't get the same kind of exact normals for each piece automatically cooked up just from facets.

You're right that just within the middle part of a the sphere that automatically generated normals are ok, that happens to be in an area where the polygons are going to be all regularly sized and distributed.

- Michael