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