Again, a rotating mirror at 6000 RPM is something I wouldn't like to have close to me. Also, you are limited to a plane from which you observer the illusion, what we do is fully 3D.

But not immersive, I wouldn't want to be nearby that 6000 RPM rotating mirror :-).

Thanks for your comments. What you mention is indeed a problem, and that is the non-uniform scattering of light in a droplet of water. Well, it turns out that this problem can indeed be turned to an advantage. You can use this to produce walls that are only visible from one direction but not the other, and this is indeed a good way for producing "opaque" objects, not "translucent" objects as you see in our demo. If you are interested, I'd be glad to have a discussion with you about these matters, mressl@gmail.com.

But it's not immersive, you can't go in there. And you can't project colored objects.

You are right on track. 100 projectors is the minimum number of projectors that make individual rays so dim as to make them invisible, so you only see the projected volume. You'd need 500 projectors, to get good rotational resolution.