Yeah, I noticed the other traptown thread was closed so this is probably a mistake posting this but I do have an answer for his question. The reason they're not attached is for playability issues. They do this all the time in current maps in HL1. Apparently not connecting pillars to the top of a roof will improve the r_speeds a little bit. If you're a mapper you would know this. It wouldn't surprise me if they did it in HL2 also, a lot more so because it's already gonna be a hard enough game to play at fast speeds as it is.