Thanks a lot. I have another pointer pointing back to a host class, which makes things complicated… My final solution was to give up deepcopy and implemented a self.copy() function. But why deepcopy does not work for the nodepath added to the CollisionTraverser?
CollisionTraverser does not implement a __deepcopy__ method. Even if it did, it’s not obvious that a deepcopy would require it to copy the entire scene graph attached to the collider.