Hi Everyone,If you're getting this error when exporting (I've had a few times in the past and can't remember if anyone showed me how to fix it), then read on to find out what I did to fix it.I had made some window polygons from a holes in door, detached them as window objects and then exported the model. The program complained about "Assertion Failed" in a .cpp file and then would close itself. Restarting the program and trying many different things like "remove isolated vertices", "reset scale" and the good old "weld selected vertices", I finally identified the offending part - one of the window objects. I deleted it recreated it exactly the same way and it exported fine (weird!!!).If anyone knows a much more easier way to fix this exporting error, please post it!Rotorhead.

Rotorhead,Thanks for your help.Thanks to you I still have some hair left !!Regards/Matts