Hi Brian, N-gons can tend to be one of the more difficult areas.

For most systems to display the n-gon will require triangulating it, and it is a pretty difficult task to make a good quality triangulator that will work correctly on complex n-gons.

Furthermore until MoI came along it was not very typical to get a whole lot of n-gons in transferred data, since there are no other CAD programs that will generate them from CAD data - that is a unique feature that has been introduced by MoI. So that means that typically programs have not been tested quite as much during their development with complex n-gons.

That can add a few wrinkles into the mix.

If you run into these problems then you can use the Quads & Triangles option to break N-gons into the more typical quad and triangle type polygon output when exporting from MoI, that is a more "well worn" and well tested type of data.

But the n-gon export is nice when the receiving program can deal with it well, since it keeps your mesh wireframe more orderly and clean.

For 3D coat's particular use though like I mentioned it probably wants to have a certain style of mesh structure with more finely diced polygons instead of big broad polygons of any type, whether n-gons or not.

- Michael