With regard to ISceneNode::remove()

[CuteAlien]

No - adding a drop() call to remove() when the parent is 0 would be wrong. Because the scenegraph wouldn't have added a reference - so dropping it would be bad. For example you can set a parent to 0 for a sceneobject which had a parent before. This will cause a drop. Adding a second drop() on remove() would crash it then. Also then it would start to be complicated to explain when to use/not use drop. So far it's simple - when you created an object with new (your case) or a function starting with the word create then you have to call drop() in Irrlicht. Or when you called grab() yourself.