Go back into object maker, and click on the object in the list, click on the "mesh" tab, and click on the button for "own collision". Now, go back to the original tab "object", and click test. Now, run up against it! It should be hard now. Press esc, and click quit. Now, click save!:) Do that with every object!!! And then when your done with every object, click the "export" button, in the "object" tab. xD