## Calculating projection

I’m going to use an InFocus IN3916 short throw projector to project the live-edited video for Body Island. The video is 1280 x 720, and I’m looking to make it a really immersive experience, like sitting close to the screen at the movies. The screen will be suspended over the sloping hill, roughly parallel to the slopes of the quarter pyramid (17˚ angle on the central ridge, but the screen could be as much as 30˚, or more). This handy site, pointed to me by Andrew Lazarow, helps calculate throw-to-distance ratios for specific models, as well as differences when changing lenses, ambient light levels and gain on the projector.

I’ll have to figure out a way to suspend it from the ceiling to get a good distance from the viewers on the slope. At a throw distance of 12’6″ the screen becomes 13’10″ x 24’8″ with a diagonal of 28’3″. At that size, 12′ is too close for people to watch– the pixels will be enormous and the image tile-ish. That could be interesting, and might go well with all the tile imagery I’m working with, but I think I’d rather have the image clean. We’ll see. The theater has a fly rig system so I can just pull a few ropes and adjust the height and pitch at will! Mounting the projector to a fly pipe might be a difficult task. Having the projector sit on a column in the center of the ridge is an option, but I think people walking around on the slopes would cause jiggles and vibration in the image.

The calculation website recommends a minimum viewing distance of 32′ at that throw distance, which is possible, but I’d have to suspend the projector fairly low to account for the pitch of the screen (17˚-30˚). Tomorrow is the production meeting, so I’ll probably be able to figure it out by then. Now to put my drawings into the diagrams of the space, using Illustrator. (and I can take the opportunity to fix some miscalculations!)

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