Thanks for the reply. I've tried this a bit on my freedir planes, interpolating to the freedir tunnel. Not really a beauty, to be honest. More ore less, what I'm looking for is the same effect as TBL / Captured Dreams, second freedir tunnel. http://ada.untergrund.net/?p=demo&i=254
The second to last screenie on that one. I have no idea how to deform the tunnel like that. Any clues ?