I am making this plugin that makes a volume out of a MeshInstance and then adds the resulting nose to the mesh as child. It worked out in the end, except for one problem.
The generated volume node doesn't show up in the scene tree. How are users going to edit it if they can't select it from the scene tree? How do you get it to appear?
you need to set owner to the new node, something like this.
new_node.owner = get_editor_interface().get_edited_scene_root()
Thanks man! :-)