Here's the deal. I want a room in the map to be completely invisible, even from people with noclip.
My first thought was to make the outside of the textures completely black so they'd blend with the void. However, since source doesn't render the first texture between void and inside the map when you're in the void, that didn't work as you'd see X-ray right into the room.
My next thought was to construct a pure black box around the room so that Source would not render that, yet still render the room inside. However, that doesn't work because you can see fog inside the box.
Does anyone know how I can go about making a room completely invisible? Thanks.
Uhh... black won't work. It will show up as a solid black area within the hall of mirrors. Basically the only way to do it is to put your map at one end of the grid and the room at the other, and use simple distance to make it hard to locate.
Since it looks like it's impossible to make the room truly invisible (unless you did what Boojum said and use trigger_teleport), why not make it visible but unreachable? And if people use noclip, just line the walls with trigger_hurt so that when they try going into it, it'll just kill them?