Questions on Intersecting

[Josellis]

I am designing a map, and I have found a few times that intersections can be very hard to remove in a way you want, especially when the intersection involves several brushes at odd angles.

1. What happens if structural brushes intersecting?

2. What happens if detail brushes intersecting?

3. What happens if detail brushes intersect with structural brushes?

4. What happens if trigger brushes intersect?

5. What happens if trigger brushes and other brushes intersect?


When answering, please don't just say "it's ok" or "don't do it", explain what happens (major slow downs while playing and/or compiling, bad collision detection (leading to getting stuck or falling through the map), or any other errors/inconveniences that might occur)

[Taiyo.uk]

Remember that the compiler splits the volume defined by the structural brushes into convex portal volumes. Therefore intersecting structural brushes should not be a problem per se, but it should be avoided. It creates a messy .map for starters. Detail brushes are not considered by the compiler in the vis stage but do affect the collision detection. Again, intersections should be avoided, for a neat map and neat clipping. Trigger brushes define a volume that will activate the trigger when a player touches it, if two such volumes overlap then both can be touched and activated at once.

Intersection removal is best done by the clipper - vertex manipulation can lead to odd results because other vertecies will be moved automatically to keep the brush convex, whereas it's not possible to use the clipper to make a concave volume. Be sure to caulk the hidden surfaces you create by clipping the intersections.