Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site lanl.ARPA Path: utzoo!watmath!clyde!cbosgd!ihnp4!mhuxn!mhuxr!mhuxt!houxm!mtuxo!mtunh!mtung!mtunf!ariel!vax135!timeinc!phri!pesnta!amd!vecpyr!lll-crg!gymble!umcp-cs!seismo!cmcl2!lanl!rmc From: rmc@lanl.ARPA Newsgroups: net.graphics Subject: Re: fractals Message-ID: <27736@lanl.ARPA> Date: Sat, 29-Jun-85 12:16:55 EDT Article-I.D.: lanl.27736 Posted: Sat Jun 29 12:16:55 1985 Date-Received: Tue, 2-Jul-85 05:38:27 EDT References: <1909@ukma.UUCP> <243@kovacs.UUCP> Organization: Los Alamos National Laboratory Lines: 33 > In article <1909@ukma.UUCP> sean@ukma.UUCP (Sean Casey) writes: > >I'd give my right arm for some good 3-D fractal generators. Like Mountains, > >or those swirly 3D things I saw in a magazine once. > > Last year, I wrote a fairly complete package for generating analytic 3-D fractals ("those swirly things"). The code (a) calculates boundary representations of fractal surfaces generated by iterating polynomials over the quaternions and (b) casts the model into a z-buffer, with interpolated shading. (Fractal surfaces are infinitely discontinuous, so where's the normal?) I wrote the course as a term project in CS175, Harvard's lab course in computer graphics. The code is thus available to anyone who wants it. (It runs on 4.x and it's all written in C; the output files are fairly standard pixel maps.) The code was written as a real fire drill; I won't maintain it now, but it did work quite well in the not-too-distant past. A high-resolution run takes hours on a 780 with FPA (all the calculations are integral, so there!), but the resulting pictures can be quite dramatic. Please let me know if you're interested. R. Martin Chavez (rmc@lanl.ARPA) Q-4 Nuclear Safeguards Mail Stop E541 Los Alamos National Laboratory Los Alamos, NM 87545