I've got a very simple 3d model in AutoCAD 2007. Just a closed polyline extruded straight up. I've tried several times to upload it, and keep getting the same error message: Here's the error message; it may help you determine what went wrong: The fileformat of your object cannot be processed by our software. Please investigate the problem and try again. I've gotten one file to be accepted by your system (3rd attempt), but it was too large and out of my budget to print. I scaled it down to a more affordable size, but have been unable to get your system to accept it in its scaled down form. I've tried simply scaling down the model that I was able to successfully upload, I've tried scaling down the original polyline and re-extruding, and I've tried re-drawing the entire thing at the smaller scale and extruding that, all with the same error message. I know you're willing to convert for me, but I'd really like to master doing it myself so I don't have to bother you with it. Has anybody else experienced problems exporting .stl files from AutoCAD 2007? Any help would be greatly appreciated. edit: I think I may have discovered the problem...I've got filleted corners on my object, and I think AutoCAD is screwing up the exact location of the intersection between the arc and the line. If I explode my 3d solid into lines and try to re-covert to a polyline, it breaks at the transition from stright line to arc in the filleted corners. I'll keep playing with it and see if I can figure out how to make it stop doing that.