This ARKit+SceneKit project shows how to “track” vertical planes (relative to horizontal planes anyway), and how to occlude objects with real world geometry. There is no cheating or magic in this app, this stuff is not really possible with (the current version of) ARKit out of the box – basically you need to tell the app about where the walls/real world geometry is. THEN the app sets up the appropriate masking planes and physics bodies. This is then used to bounce balls of the walls as well as occluding the