said by milnoc:
So get four 1080p projectors, and align them just right.
Well, we actually did try to overlay two projectors to double the light output. They both had lens shift, but getting them close enough to look like a single image is a nightmare. Side by side wasn't good enough, so we had to stack them on top of eachother, but then it wasn't quite right even with lens shift so we had to fold up paper and shimmy it between the things in the right places...
Needless to say, we decided not to do this for the convention.
Combining multiple projectors for a bigger (or higher-res) image is a bit easier, but you need a vision mixer that supports it, and you lose a bit of resolution at the blend point. Basically the mixer has each projector fade to black along the joined edge, so you overlap them in that part, and because they fade from one to the other you don't have to be as precise because it's hard to see the seam even if they're not perfectly aligned. That's mainly intended for doing multiple images side-by-side, though, not 2x2.--
Developer: Tomato/MLPPP, Linux/MLPPP, etc »fixppp.org