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From: robert@texas.asd.sgi.com (Robert Skinner)
Newsgroups: comp.graphics
Subject: Re: rotoscoping
Message-ID: <1990Oct23.204359.18883@odin.corp.sgi.com>
Date: 23 Oct 90 20:43:59 GMT
References: <13485@sdcc6.ucsd.edu>
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Reply-To: robert@sgi.com
Organization: Silicon Graphics Inc., Entry Systems Division
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In article <13485@sdcc6.ucsd.edu>, cs161fhn@sdcc10.ucsd.edu (Dennis Lou)
writes:
|> 
|> What is rotoscoping?  Where can I learn about it?
|> 
|> I have Foley and Van Dam's
|> _Fundamentals_of_Interactive_Computer_Graphics_ but it doesn't say
|> anything about rotoscoping.  I have also searched the past 250
|> articles and sent a request to the graphics bibliography archive
|> server.
|> 
|> Thanks

There is another form of rotoscoping that is sometimes used in computer
graphics to capture motion for animation or motion studies.  If video
tape an actor from two angles, you can use triangulation to determine
the 3D coordinates of key points on the body, usually joints.  You now
have what you need to animate a synthetic actor going through the same
motion.

Rotoscoping was used to generate the motions of Abel's "Sexy Robot"
commercial (~ 1986?), and for the tiger in Bio-Sensor (1984).  I'm
sure there are others, although good animators and faster dynamics
simulators are catching up on rotoscopings inherent limitations

	* motion for which there are no actors (dinosaurs)
	* motion that is hard or impossible to record (free fall from 
	  a plane, or something in outer space)
	* motion that is dangerous to the actor (being thrown from a
	  rolling automobile)

Robert Skinner
robert@sgi.com

	When two people are under the influence of the most violent,
	most insane, most delusive, and most transient passions, they
	are required to swear that they will remain in that excited,
	abnormal, and exhausting condition unconditionally until death
	do them part.
			-- George Bernard Shaw