sowth's Journal: Swept volume display?

I saw this post by russotto on the 3D TV article:

Well, there's the old rotating disc displays, with a disc which sweeps out a volume; the image is projected onto the disc. The disc is still 2D, but the light from the image to your eye is actually coming from a space, not a plane. Apparently similar things are actually used; the generic name is swept-volume volumetric display.

Sounds like something one could do with a projector display, electric motor, white flat piece of cardboard, and microcontroller. Would make a nice garage project sometime...