}
throw new RuntimeException("addSceneGraphObject invalid argument ="+obj.getClass());
}
public void addRef(SceneGraphObject o) {
Animator a=(Animator)getGraphObject();
boolean forced=forceCapability(Group.ALLOW_CHILDREN_EXTEND);
SceneGraphObjectHolder res=Universe.findHolder(this, o);
a.addGraphObject(o, res.getSceneGraphNode() , _ad);
if(forced) restoreCapability(Group.ALLOW_CHILDREN_EXTEND);
}