Article View: net.graphics
Article #1544Re: Y positive up or down? / Left or right-handed?
From: Jon Leech
Date: Fri, 31 Oct 1986 17:27
Date: Fri, 31 Oct 1986 17:27
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1915 bytes
In article <1338@batcomputer.TN.CORNELL.EDU> garry%cadif-oak@cu-arpa.cs.cornell.edu writes:
>A related question: in 3-D, do people like left-handed coordinates,
>right-handed, or programmer-choosable ?
>...
>I heard a rumor once that most solid geometry books are right-handed...
>
>garry wiegand (garry%cadif-oak@cu-arpa.cs.cornell.edu)
This is another of the innumerable religious debates in computer
graphics. An amusing story along these lines: Jim Blinn has done a great
deal of computer generated material for the PBS series ``The Mechanical
Universe''. His SIGGRAPH film 2 years ago contained portions of this
material with his own narration. At one point, while talking about
tops or some such, he said 'of course, vectors obey the right-hand rule',
which received applause from the knowedgable members of the audience.
Jim's rendering software uses LHS internally, leading to more work than would
otherwise be neeeded. The point is that if you're doing modeling based
on real physics, you work in RHS - and it makes life that much easier
if your other software talks the same coordinate system.
-- Jon Leech (jon@csvax.caltech.edu || ...seismo!cit-vax!jon)
Caltech Computer Science Graphics Group
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Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: arc1-ca.pugleaf.net!utzoo!watmath!clyde!rutgers!seismo!ll-xn!cit-vax!oddhack!jon From: jon@oddhack.Caltech.Edu (Jon Leech) Newsgroups: net.graphics Subject: Re: Y positive up or down? / Left or right-handed? Message-ID: <1102@cit-vax.Caltech.Edu> Date: Fri, 31-Oct-86 12:27:28 EST Article-I.D.: cit-vax.1102 Posted: Fri Oct 31 12:27:28 1986 Date-Received: Sat, 1-Nov-86 04:30:24 EST References: <1338@batcomputer.TN.CORNELL.EDU> Sender: news@cit-vax.Caltech.Edu Reply-To: jon@csvax.caltech.edu (Jon Leech) Organization: California Institute of Technology Lines: 22 Keywords: Handedness, Physics, Religion