The spline modeler definatly creates a VERY high poly count when converted. I would sugest following Hoofdcommissaris advise and re-create in the vertex modeler. I don't think it would be that tough, and you would have the added advantage of being able to do your UV mapping with the new UV editor in the vertex room! Maybe convert your model to vertex, (do a save as,) recreate a lower poly-count model right besides it, (saving as frequently!) and then exporting the final object as an OBJ file instead of a DXF file. DXF is a notoriously BAD file to transfer between programs... even though that IS WHAT IT WAS MADE FOR! (The software gods were LOL-ing THAT day!) Good luck!