Hi Brian, well 4 of the formats you list there will rely on your target application to convert the NURBS data into a polygon mesh.

This includes your:

#1 .3dm from MoI -> import .3dm into Carrara (meshed on import into Carrara)
#2 .3dm from MoI -> import .3dm into Amapi (is this correct?) -> export .3dm from Amapi -> import .3dm into Carrara (meshed on import into Carrara)
#3 .3dm from MoI -> import .3dm into Amapi -> export .obj from Amapi -> import .3dm into Carrara (meshed on export from Amapi)
#4 .igs form MoI -> import .igs into Carrara (meshed on import into Carrara).

If you're seeing strange polygonization in any of these routes, you should contact the authors of the program that is performing the polygonization to see what might be going wrong. In all of these cases it is not MoI that is generating the polygon information.

The polygon information is what actually gets finally rendered, in all cases.

The route that I have the most control over is when you export a mesh format from MoI.

LWO is generally not the best except for going into Modo, LightWave, or Blender.

Programs other than Modo or the Blender LWO importer will not read vertex normal smoothing information from the LWO file, and instead will calculate smoothing by averaging adjacent faces. This can lead to some shading errors.

If you must use LWO export, it is probably a good idea to switch to Output: Quads & Triangles. If you export n-gons then you are also relying on your target application's ability to convert the n-gon into triangles, and this is another area which can be messed up fairly easily.

Generally the best bet is to use OBJ format, since that can translate vertex normal information over, which really helps to generate a smooth object.

Some programs deal with unwelded information better than welded information in OBJ files, so you might try expanding the meshing options dialog and uncheck "Weld vertices along edges".

OBJ file also have the option of using n-gons or quads & triangles. Again using quads & triangles here can help avoid n-gon triangulation problems in your target application.


So an overview: try OBJ export, switching 2 options - change Output : n-gons into Output: Quads & Triangles, and expand the dialog by the arrow in the lower left corner and un-check "weld vertices along edges".

Does that type of OBJ export work more reliably for you?

- Michael