Hi Okapi,

> Would it be as difficult to convert a model made up of quad and
> triangles into a set of nurbs, so that each face is a nurbs surface
> (tri or quad) ?
> So all polygonal curved models would be translated as a serie of
> nurbs quads or triangle surfaces.

It's not too difficult to implement as far as writing the code, but unfortunately it does not tend to produce very good results except for in the special case of a model that is supposed to be faceted like a diamond for instance.

NURBS models are generally intended to have curved surfaces made up of larger smooth single surface sheets and it does not fit very well into the overall NURBS structure to have geometry that should be smooth instead be diced up into a lot of little tiny planes.

I actually added a command for that in Rhino, called MeshToNurb as described above.

However, check out this post from someone who currently works on Rhino support - he wishes that it would have never been added because it causes a lot of problems and tends to lead people down a path giving bad results...

So I'm not exactly too excited to go down that path... But if you really do need to do that now, Rhino's MeshToNurb (or I think Sycode.com has a mesh to solids program also) can do exactly that kind of a process.


Eventually maybe I'll be able to figure out some better way to handle polygonal data imports. Maybe if I had a special command that was for importing "reference geometry" or something like that rather than having it in the regular Open file list.

- Michael