I have done some research on possible collision problems related to SketchUp backfaces.
The problem is that every face in a SketchUp model has both front and back sides, but the collision engine will freak out if you export both. So, the solution is to make sure every visible face is facing out and them exporting ONLY front face.
To find backfaces, go to View -> Face Styles and choose "Monochrome". Now, if you are using default settings, backfaces will be blue, while front faces will be white. If you find a backface that should be visible, click on it, go to Edit -> Face and choose "ReserveFace", that should fix it.
There's also a very handy plug-in called Front Face, which will quickly turn a backface into a frontface (again, use Monochrome face style to find them in the first place). |