public void clear() {
		for (int i = rigidBodies.size() - 1; i >= 0; i--) {
			RigidBody rigidBody = rigidBodies.get(i);
			physicsController.removeRigidBody(rigidBody);
			graphicsController.removeRigidBody(rigidBody);
			rigidBodies.remove(rigidBody);
		}
		lights.clear();
		lightsBranchGroup.removeAllChildren();
		wireframeRigidBodiesBranchGroup.removeAllChildren();
	}