So I've got some tunnels and cliffsides, and they all work OK for the purposes of checking paths and map effects... but but now I want to add displacement goodness, but it turns my "tunnels" and "walls" into the VIS-equivalent of swiss-cheese. So here's my question to the forums: Any tips for this? And if I made a program that would auto-magically "back" a displacement brush with another nodraw brush, would it be useful? I've already got a small Python script that parses the VMF. I figure it might be an interesting project to have a script that goes and... Identify all displacement brushes. Identify the non-displacement faces of those brushes (let's call them "emtpy sides" for lack of a better term.) Find empty sides which are not entirely flush with a VIS-blocking brush. Add a nodraw "cap" in a custom visgroup. Or am I trying to go after a mostly-solved/unimportant problem?