Antiportals

Quick definition: An antiportal brush acts like both a hint brush and an areaportal brush mashed into one single entity. Unlike areaportals, antiportals are not restricted to the inside of door brushes. Unlike hint brushes, antiportals do not create VIS splits and add to the visdata size.

Antiportal restrictions:

• Antiportals cannot be lined up with structural brushes or the default 1024X1024 engine splits or they will cause a leak in your level. This is because they are like a void to existing portals and will devour them causing a tear in the level's hull. They can be lined up with detail brushes.
• Antiportals cannot be visible in playable space or they will give you the nasty HOM effect. You must bury the antiportal faces of the brush inside of detail and/or structural brushes.

Uses and other information:

• You always use the skip texture in conjunction with the antiportal texture. Only one face of a brush needs to have the antiportal texture. The rest should have the skip texture.
• Antiportals are easiest explained by trying to think of an Areaportal and a Hint brush all in one without a great deal of the downfalls.
• Antiportals are best used in terrain maps, where a designer is trying to find ways to have VIS blockage in between terrain sections.
  
  • A structural brush (caulk or sky) that is jammed into the terrain and lifted to just under the top of the terrain or to the ceiling in the case of a skybox brush adds to the visdata size. This in turn can result in adding bulk to the .bsp file.
  • A well placed antiportal brush can be used to create the same VIS blocking wall in a specific terrain piece. The benefit over structural brushes comes in the form of no extraneous VIS splits. Using structural brushes and/or hint brushes to block VIS creates VIS splits and increases the .bsp file size. Antiportals do not cause VIS splits, yet they give you the same VIS blocking effect that hint and/or structural brushes give you.