Hi Iwan, I missed this part of your message:

> Also, the mesh export is always more or less.. bad ! I thought it was
> 3dsmax import but I tried in deep exploration, meshlab... and it always
> went with mesh discontinuities, cracks and smoothing problems.

Hmmm, can you post a small example .3dm file of something that is causing you problems?

If you have separate surfaces in your model, make sure to join them together so they are one connected object before you export to a mesh.

When you have joined pieces, MoI does extra work to make sure the created meshes have a common vertex structure along the shared edges. If you have just individual surfaces, that extra work won't be done and each object gets meshed slightly differently which can result in cracks.

Possibly PowerNurbs is doing an automatic join step for you or something...

If you have things joined together and you are still getting cracks, then that would be a bug, please send me any examples you have of this so I can fix them up.

Also, which file format are you using? If you are using OBJ format, it is possible that 3dsmax is not doing a good job of processing n-gons (more than 4 sided polygons). If that is the case you may be able to get a better result by switching the Output: option to "Quads & Triangles". It is not too unusual for programs to have difficulty in processing complex polygons with a lot of sides, I'm pretty sure that PowerNurbs does not export n-gons so that may be another difference that explains what you are seeing.

- Michael