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From: brian@hpfcdj.HP.COM (Brian Rauchfuss)
Newsgroups: comp.graphics
Subject: Re: ERRORS IN ROTATIONS
Message-ID: <17400017@hpfcdj.HP.COM>
Date: 4 Jan 90 04:51:17 GMT
References: <1990Jan2.163405.24094@ibmpcug.co.uk>
Organization: Gremlin Lovers Anonymous
Lines: 18


One method which would eliminate scaling would be to use quaternions.
Quaternions are a compact form of representing rotations, and they combine
easily and faster than matrixes.  They *only* represent rotations, so any math
errors after a few thousand rotations would not create any weird scaling
problems.  You would combine the rotation quaternion with the viewing matrix
before drawing.

"Quaternion Calculus as a Basic Tool in Computer Graphics", Daniel Pletinckx
The Visual Computer 5:2-13, (1989)

"Animating Rotation with Quaternion Curves",  Ken Shoemake
ACM 0-89791-166-0/85/007/0245

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Brian Smokefoot              "... never knowing I could shape my life
brian@hpfcbdr.HP.COM         like the artist paints his dreams
                             on a canvas." - Minor Detail