Hi Filax, after some more inspecting, I think my problem was not so much the format, but my workflow. I believe now that the thing with my terrain mesh as x, is that the vertices were unwelded (if so, must have happenned at the slicing time). Now, I didn't checked that one before because in blitz everything seemed ok (visually there were no problems). That's just a theory, because I'm using ultimateunwrap to save my geometry, so I don't really now if it's the import module of ultimateunwrap or that my .x model was corrupted to begin with. Just posted in case this helps.