broken smoothing groups. follow this tutorial http://www.beamng.com/threads/how-to-correctly-import-export-official-vehicles-via-blender.14793/
dat smoothing group speaking of long distance cannons now thats long distance 4.1 km in beam ng thats intercontinental even massive compensation cant make you bigger / i think i found a sinkhole / looks its a ato... oh its only a rc car wtf i didnt spawn this / eah / who left this oversized toy her.... oh wait its a real balez weee
if you use blender, edge split is the answer. use this modifier on all parts that are "puffy" set to about 40°, not the default 30°. That's at least how i'm doing it. on phone again , so no screen.