Hi Mark,

> It could of course be bad modeling on my part.

Doesn't look like it to me - it looks like a problem with Kerkythea's triangulation mechanism.

But yes, exporting triangulated from MoI (or probably Quads & Triangles should be fine) should avoid this problem.

It's pretty difficult to make a triangulator that handles all kinds of complex concave n-gons properly, if the algorithm gets confused, it is easy for it to try and connect up a triangle between 2 points where it shouldn't because it will cause a "leak" outside of the boundary.

- Michael