Potentially seeing through walls: a performance issue

[Phoroneus]

Unorthodox architecture tends to cause problems, like if you have too many indirect routes open to an out-of-view area, it will be rendered anyway. In a recent map experiment, I made the internal walls of a dungeon about a meter shorter than the ceiling, giving a clear space overhead. The result was a huge drop in performance, which was instanly resolved when I lowered the ceiling to be level with the tops of the walls.

Without knowing how the engine calculates what to render, I'm not sure anyone can help further beyond personal experience. I remember some games I used to map for had clip brushes that would act as solid objects (even though they were non-solid and invisible) in order to split large planes and block areas from being rendered before the player actually got to them (like areas beyond fog, around yet-unreachable corners, et cetera). I don't think HPL has anything equivalent, unfortunately.