garry@batcomputer.TN.CORNELL.EDU (Garry Wiegand) (10/30/86)
Yo: another vote for Y positive up! For graphics, that's what seems to be human/natural. A related question: in 3-D, do people like left-handed coordinates, right-handed, or programmer-choosable ? I was raised on left-handed, but just yesterday I had someone being very confused while twirling the camera around -- he was thinking right-handed! So, fine, let it be selectable - but then think of a programmer who picks one way who calls a library routine which was written using the other way. Muchos confusing. Better to make everybody agree ? I heard a rumor once that most solid geometry books are right-handed... garry wiegand (garry%cadif-oak@cu-arpa.cs.cornell.edu) (The opinions expressed above are indeed those of my company.)
jon@oddhack.Caltech.Edu (Jon Leech) (10/31/86)
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 __@/
majka@ubc-vision.UUCP (Marc Majka) (11/03/86)
In article <1338@batcomputer.TN.CORNELL.EDU> garry%cadif-oak@cu-arpa.cs.cornell.edu writes: >[...] So, fine, let it be selectable - but then think of >a programmer who picks one way who calls a library routine which >was written using the other way. Muchos confusing. Better to make >everybody agree ? Better to make the library smarter. --- Marc Majka