How Big is too Big for a Map?

[MrBehemoth]

HPL2 uses occlusion culling (objects aren't rendered if they are entirely hidden behind other objects) , as has been said, but from what I can tell it's not too precise.

I'm not 100% sure that hat Mudbill said about having gaps stopping occlusion culling from running is right. I think this would be more relevant to BSP based engines (eg Source) where the culling is pre-processed.

My 'educated' guess is that HPL2 aproximates this effect simply by culling what you can't see based on AABBs (axis aligned bounding boxes), although I could be wrong...

In practise then, this means it helps to space things out. A map laid out like a house, where the walls are 6 inches - 1 foot thick is likely to cause a slowdown. A map with big gaps, as if the walls were 2-4 metres thick or more, should help the process of occlusion culling. This is something I realised since make The Trapdoor, which has some dense corridors which drag the framerate down in places.