I just want to know how to create a room inside of a building. I don't want to teleport anywhere, just make it so, once I enter through the door, the roof disappears, while you are inside that is. Then when you step out of the door, the roof goes back on, something like that.

I don't want to have to put a teleport like thing in the coding, I just want it simple and on one map.

If I anyone can tell me this, I'll be real grateful to you.