Ive been working on a map which involves a lot of tunnels and vents. The vents are fine its just when I put in my tunnels and compile, ALL the entities including lighting and such are removed from the compiled map as if because of these tunnels they fail to compile with the rest of it. To make the matter worse the tunnels arent even present on the compiled map either. Only the brushes remain. Im using 1 sided displacments for the tunnels which im not even sure how to make since I "borrowed" them from another map. The tunnels worked fine before when they where flat but when i displaced them it all went to hell. I need help.