From this thread:
I went through a good portion of the map in question in the thread linked above, converting most of the func_walls to func_illusionaries and placing simplified clip brushed over them with the idea that it would decrease clip nodes. Then I compared the compile logs before and after, and as it turns out, my clip nodes had increased. What I initially assumed is (to the best of my knowledge) true: brush entities DO NOT CREATE CLIP NODES. I know that they block player movement, but apparently they do so in a different way than world brushes (one that doesn't add to the clip node count.) Therefore, adding clip brushes over brush entities is pointless and only creates more clip nodes. Proof:Without knowing for sure, my guess would be a func_wall WOULD create clipnodes, because it creates a solid surface the player can touch, jump on top of, etc., where an illusionary obviously forms no barrier, so it creates no clipnodes..Exactly. And thus it's pointless to turn very small brushes or groups of small brushes or brushes that are one unit thick into func_walls. Turn them into illusionaries instead. They're to small to stand on, what's the point of making them func_walls?
