Hi 4rw1n, there are 1 or 2 degenerate faces in the model with all their surface area completely trimmed away and the UV coordinate bug (division by zero) happens when processing those particular faces. I've got it fixed for the next v4 beta release. Thanks for reporting the problem and for sending the model so I could find the bug.

For the moment, turning off UV coordinate export as described above should avoid the bug.

- Michael