Really sketchup models are horrible to even attempt to use, most of them are poor at credits, so we really frown upon them, sketchup conversions are generally not allowed unless made by YOU using sketchup.  Sketchup doesnt make a model very cleanly so it makes junk models compared to other apps out there.  For the purposes of just showing off the models sketchup is fine, but not application in a game.   More of an issue you need to ride em about tbh, they credit you but not the other people you