# Peculiar geometry behaviour question (antichamber)

Hello,

It’s really hard trying to put my thoughts into words with this question.
So here’s a description of what I wish to achieve. If there is anyone who can push me in the right direction then I can’t thank you enough. ok, here we go:

Imagine an empty room with a door in the middle, there are no walls surrounding that door, it’s just there all alone. But when you open the door you don’t see the back of the room you’re standing in. no, you see the wall of an entire new room. (This might be the hardest thing for me to explain)

So: You are in room A, you open a door in the middle of the room (with no walls around it) and when you go through it you are in room B (which is impossible in reality)

Does anyone have any idea how I can do that with unity? I don’t need codes worked out for me or anything, a push in the right direction is all I’m asking.

The same phenomenon is seen in Antichamber (the game).

EDIT - BETTER SOLUTION → http://forum.unity3d.com/threads/191890-Unity-4-2-Stencils-for-portal-rendering

This kind of behavior can be achieved using RenderTextures. Unfortunately it’s a Pro only feature, so if you’re working with Unity Free you’ll have to come up with another method.

Basically, you have the door, as you explained it. Immediately behind the door you have a teleport to handle the player from moving to this room. Immediately behind this teleport, you’d have a RenderTexture that just renders what a camera sees. This camera is placed in the other room, to the location of the door. This setup will cause the door image to be static, in the sense that it won’t change if the player looks at it from a different angle.

If you want a better 3D effect for the RenderTexture, you will have to move the camera in the other room based on the movement of the player, so it seems the space behind the door is, in fact, 3D.