Portals: Difference between revisions

Within certain levels there are World Portals (Brush entity, <code>$TODO</code>).  These are invisible portals that can be used to create the illusion of a larger area - for example, {{Spoiler text|As a player enters [[Chapter 6]] of ''[[Portal 2]]'', they fall down a long tube. The length of this tube is exaggerated via the use of World Portals.}}