Hi DesuDeus, I've got the bug fixed for the next release. It was a bug when handling a degenerate totally squashed down edge trying to use it as the boundary of an interior hole of the surface, when the degenerate edge was located right at the outer edge area of the main surface. It crashed when trying to divide the surface to "break" the hole.

Thanks for reporting the crash and for sending the file to test with, that helps a whole lot to have the file to work with.

For the current release if you just delete that little knob at the bottom and import the new version I posted above that should allow you to export out with the current version ok.

Thanks, -Michael