Hi Radiance,

> the issue is that people are giving me models from moi3d that do
> not, as you say you do, multiple references to the same vertices
> with diffferent vertex normals.

That will depend on whether the "weld" option was used when exporting from MoI or not.

I would actually suggest to focus on the unwelded case first since that is more simple, that's when there is the same number of 3d, uv, and normal vertices and the faces reference the same index in each.

The cylinder case I posted above is unwelded, but it still does not render properly (in Octane that is, it renders properly in all other renderers), it shows seams between faces but if the vertex normals from the file were used to do the shading there should not be any seams present.

Maybe look for a bug where in some cases you're using the face normal instead of the vertex normals from the file.


I think your problem is that you are only accustomed to working with polygon mesh modeling program output, and in poly modelers it is more common to recalculate or modify the normals a lot (with smoothing groups, etc...) but you should not try to do such things with the output from a CAD program where the normals are actually coming from a more accurate NURBS model so if you manipulate them you are actually messing things up instead of fixing things.

- Michael