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From: jk87377@cc.tut.fi (Juhana Kouhia)
Newsgroups: comp.graphics,comp.graphics.visualization
Subject: Re: how to view f(x,y,z) = constant surfaces ?
Message-ID: <1991Mar15.233844.20616@cc.tut.fi>
Date: 15 Mar 91 23:38:44 GMT
References: <1991Mar14.234739.15281@athena.mit.edu>
Organization: Tampere University of Technology
Lines: 28


In article <1991Mar14.234739.15281@athena.mit.edu>
chasman@athena.mit.edu (David Chasman) writes:
>
>My current technique is to evaluate f(x,y,z) for all discretized
>(x,y,z) inside of a cube - and to light up a point 
>if :
>	 | f(x,y,z) - constant | < Epsilon

Try use a ray tracing (hopefully you know that method):

1. ray from eye through a pixel to the world
   Ray = Eye+t*normalize(Pixel-Eye)  ; t is distance from eye
2. calculate an intersection points of cube and ray --> t1, t2
3. for (t = t1; t < t2; t = t + small_step) {
     Ray = Eye+t*Direction;
     F = f(Ray);
     if (abs(F-constant) < Epsilon) return Ray;  /* point is found */
   }
   /* point is not found */

Rest of this home exam is your job.
I use something similar to calculate 4D Mandelbrot.
Similarly you can make this algorithm much faster, because you have a
mathematical function.

Juhana Kouhia
jk87377@cs.tut.fi
        ^^^