How to make an object of infinite height.

I’m building an arena for an FPS, set atop an incomprehensibly tall building.

  • I don’t want to have the buildings appear floating.
  • I don’t want to simply extend the base of the building a massive distance.
  • I don’t want to try concealing the bottom of the building in clouds à la Unreal Tournament’s Two Towers:

How can I create the illusion of the building going down into infinity, without a physical object or hitting the max camera distance? The same problem could apply to an energy weapon being shot into space, or an infinite wall, train, etc.

Any ideas on how to approach this problem would be really appreciated.

Model your building as if it reached a banishing point in perspective; the parallel lines, make them converge at one point.