I couldn't find a "help section", so I figured this is the best place to post for help. I've run into various problems with Hammer, specifically: Props, faces, and other things may disappear during compiling. Area portals always appear closed. These are just the major problems I'm having. I'll try to work out the others, but I might be back for help again. I'm using the Ultimate Mapping Resource Pack because I couldn't get Hammer working before I downloaded it, and the maps I've been messing with were downloaded from the Valve Maps(Decompiled) thread. A version of one of my compiled maps can be downloaded here: https://www.dropbox.com/s/m0rohj8mh3sh4wv/cp_dustbowl_red_vs_blu.bsp It has many problems.