I'm working on a map with an inside, and outside map. connected by info_playerteleport entities. The outside part is in space, with low gravity[used a func_water]. inside the ship is normal gravity. I'm trying to make windows to see whats going on outside when your inside, and vice-versa. I'm planning on having it a multiplayer map too. maybe even have onboard weapons to shoot other players. dunno yet.
I'm not sure which gui to use, or how to link them to get it to work. every time I try, nothing shows up.

Well, I used another method. Used a common 'Portal_sky" scene for both map parts. So the planets and such in the background are the same. gonna have to make a info_teleport entity to put the player inside the ship, but in the outer space part of the map, for the onboard weapon idea to work right.