From: utzoo!decvax!harpo!floyd!vax135!ariel!hou5f!hou5b!hou5c!hou5e!jjm Newsgroups: net.movies Title: Re: How does 3-D Work? - (nf) Article-I.D.: hou5e.273 Posted: Thu Mar 10 11:11:12 1983 Received: Fri Mar 11 05:19:13 1983 References: pur-ee.833 houxh.141 3D movies attempt to recreate the method by which you normally see things. That is, each eye gets a slightly different image, because it is looking at the object from a different position. This difference in viewing angle is referred to as inter-ocular parallax. 3D movies attempt to provide each eye with a different image, filmed from a pair of cameras (or other arrangement). The brain combines these two images, and voila! 3D. Two ways of doing this are A) color code two images and view through tinted lenses and B) polarize the two images and view through polarizing filters. Method A can be projected using a standard projector. Method B requires a special projector (or pair of projectors) projecting through polarizers. Most available 3D films are trashy because of three problems: A) poor filming equipment lets the images get out of alignment B) poor projection equipment makes it worse C) most directors (and cameramen) have not taken the time to perfect the art of direction and filming in 3D. American Cinematographer magazine had a special issue recently about state-of-the-art 3D filming. Special 70mm film is used, allowing the split images (each 35mm) to be recorded on the same frame. Special digitally controlled projectors are used to reduce "jitter" (a framing problem) when projected. A special screen is used that does not de-polarize the light it reflects. Disney World's new attraction "EPCOT Center" includes a special 3D theatre, showing a specially produced film. Rumor has it that the effect is marvelous, using multi-speaker digital audio to enhance the effect. Jim McParland American Bell - Holmdel hou5e!jjm