Moved from the VP discussion in the Invisible Brush of Death thread:     Interesting links as always nb. I’d not heard of antiportals before and I’ve only been studying the code since Monday but here’s my twopenceworth anyway.   I think you’d need to keep track of a separate system of occluded frustums to go with the current system of view frustums. You can’t just slice parts out of the current frustums without ending up with complicated concave 3d shapes. Right now a view frustum is good for on