I got rid of scaling the scene manually using the utiltiy method posted before. Scaling some Node has the effect that all subnodes and their spatials will be scaled during rendering as expected.
But one has to take care of creating a new instance of CompoundCollisionShape using a subnode because the CompoundCollisionShape does not take care of the scale factor of parent nodes. So in order to make scaling work on the CompoundCollisionShape you need to pass a scaled copy of the appropriate subnode to the constructor:
Node level = (Node) scene.getChild(“level”);
Node levelClone = level.clone(false);
CompoundCollisionShape complexShape =