I'm currently preparing to do a projection mapping / interactive installation in Kyoto, Japan with friend Eddie Lee of Funktronic Labs. From the brainstorming process the idea of a shoji (traditional japanese door) floating around in the forest sparked our imaginations.
As the shoji is pushed back and forth by a guest, the world seen through the paper moves and reacts to it's own position as well as the viewers. The end result is a window into another world.
This design would use a single rear projector. To track the position of the door and match the projection to it, we'll use four infrared LED's and an infrared camera. Software tool of choice remains undecided, perhaps Touch Designer or the legendary Funk Engine (Eddie's handcrafted engine).
p.s. the art inside the shoji is temporary and meant only as an example, but if your into it I don't mind