Path: utzoo!utgpu!watmath!watcgl!rhbartels
From: rhbartels@watcgl.waterloo.edu (Richard Bartels)
Newsgroups: comp.graphics
Subject: Re: Computational geometry II
Message-ID: <9460@watcgl.waterloo.edu>
Date: 30 Apr 89 13:30:24 GMT
References: <2053@incas.UUCP> <5397@cs.utexas.edu> <9455@watcgl.waterloo.edu> <9458@watcgl.waterloo.edu>
Reply-To: rhbartels@watcgl.waterloo.edu (Richard Bartels)
Organization: U. of Waterloo, Ontario
Lines: 11

In article <9458@watcgl.waterloo.edu> ksbooth@watcgl.waterloo.edu (Kelly Booth) writes:
>
>(And if you only want the orientation, you don't have to compute all three
>coefficients, just c).
>

The context of the midterm question, which Kelly forgot to mention, is
one in which the lines of sight are all parallel to the z axis.  This is
why c alone gives the (back/front facing) orientation.

-Richard