How To Make This Door Effect?

any tutorials how to make this kind of doors in hammer??

like in portal:

but if u cant understand my picture, its the door like, spiral

You mean an iris style door?

uhm YEA, sorry dont know the name of it…

i just googled it and find a tutorial from interlopers, but tnx!

http://forum.interlopers.net/viewtopic.php?t=2256