private void addGhostObject(PhysicsGhostObject node) {
        if(physicsGhostObjects.containsKey(node.getObjectId())){
            logger.log(Level.WARNING, "GhostObject {0} already exists in PhysicsSpace, cannot add.", node);
            return;
        }
        physicsGhostObjects.put(node.getObjectId(), node);
        logger.log(Level.FINE, "Adding ghost object {0} to physics space.", node.getObjectId());
        dynamicsWorld.addCollisionObject(node.getObjectId());
    }
Removes all physics controls and joints in the given spatial from the physics space
(e.g. before saving to disk) - recursive if node
@param spatial the rootnode containing the physics objects
jme3-jbullet/src/main/java/com/jme3/bullet/PhysicsSpace.java