rich@sdcc13.UUCP (rich) (05/01/85)
Dear newsgroup,
I am interested in building some fractal mountains.
Is there a place that I can look for some good algorithms, that
create mountains without big holes in the center? I all ready have
Mandelbrot's book.
Thanks,
richwfi@unc.UUCP (William F. Ingogly) (05/04/85)
> I am interested in building some fractal mountains. > Is there a place that I can look for some good algorithms, that > create mountains without big holes in the center? I all ready have > Mandelbrot's book. You should read "Computer Rendering of Stochastic Models," by Alain Fournier, Don Fussel, and Loren Carpenter (CACM, June 1982). This article should get you started on modelling landscapes. By the way, Mandelbrot objects STRONGLY to these models being called fractals. Other modelling techniques for natural objects that may interest you or someone else in the newsgroup: Particle systems - used for modelling the wall of fire in the Genesis effect sequence in the Star Trek movie (Star Trek II?). The reference is "Particle Systems - A Technique for Modelling a Class of Fuzzy Objects," by Bill Reeves (ACM Transactions on Graphics, April 1983). Also used by Lucasfilms and others for modelling plants. L grammars - a class of bracketed grammars that's useful for modelling branching structures like plants. The reference is "Plants, Fractals, and Formal Languages," by Alvy Ray Smith (SIGGRAPH Conference Proceedings, July 1984). You may also want to look into texture mapping, depending on the nature of your application. Simple polygonal structures can be given a highly realistic look by mapping a complex "mountain" texture onto them when they are rendered. -- Cheers, Bill Ingogly
sean@ukma.UUCP (Sean Casey) (06/25/85)
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.
--
- Sean Casey UUCP: sean@ukma or
- Department of Mathematics {cbosgd,anlams,hasmed}!ukma!sean
- University of Kentucky ARPA: ukma!sean@ANL-MCS.ARPA rivero@kovacs.UUCP (Michael Foster Rivero) (06/27/85)
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. > Sean (And all other fractal people) Most people working with fractals work for companies who view unrestricted distribution of code as punishable by hanging (slowly). However, net.graphics is an ideal forum for trading tips and tricks on Mountains and those swirly 3D things (which are two completly different functions, incidentally). Maybe it's time to establish net.graphics.fractals ? Any comments or suggestions from the net? Michael Rivero
turner@saber.UUCP (Jim Turner) (06/27/85)
> 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. *** REPLACE THIS LINE WITH YOUR MESSAGE *** wouldn't we all !! perhaps some kind soul in netland could post some public domain s/w in this area, in need not be a complete package, i'm sure there are lots of us who would benefit from this never re-invent the wheel -- god bless Lily St. Cyr -Rocky Horror Picture Show Name: James Turner Mail: Saber Technology, 2381 Bering Drive, San Jose, California 95131 AT&T: (408) 945-9600 x75 UUCP: ...{decvax,ucbvax}!decwrl!saber!turner ...{amd,ihnp4,ittvax}!saber!turner
rmc@lanl.ARPA (06/29/85)
> 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
hmm@unido.UUCP (06/29/85)
And what do I do with your right arm ? :-) Hans-Martin Mosner Universitaet Dortmund (Germany) ihnp4!hpfcla!hpbbn!unido!hmm seismo!mcvax!unido!hmm
haddock@waltz (07/05/85)
I was fingering the latest mag's the other day (in a bookstore,
where else?) and one of the latest rags had some sources for
fractal generation. Although I believe it was in BASIC (wretch)
I'm sure someone out there could convert it to some more reasonable
language (e.g. Scheme, C, 8086 assembly :-)). Come to think of it
the mag may have been "PC Tech Journal" but... Maybe I'll drop
$3 or $4 for the stupid thing.
================================================================
_____
-Rusty- |\/ o \ o
| ( -< O o Where's the fish?
|/\__V__/
ARPA: Haddock%TI-CSL.csnet@CSNet-Relay.arpa or Rusty@Maryland
CSNet: Haddock@TI-CSL
USENET: {ut-sally, convex!smu, texsun, rice} ! waltz ! haddockrfb@cmu-cs-h.ARPA (Rick Busdiecker) (07/09/85)
In reply to Rusty Haddock, I've got a program in C which does linear fractals. There are things which will definitely have to be changed for whatever your output device is, but if people are interested I could either post it or net-mail it to those who want it. Rick Busdiecker rfb@cmu-cs-h
rns@aicchi.UUCP (Schreiner) (07/23/85)
SCIENTIFIC AMERICAN August 1985 Has some very interesting full color pictures of fractal dragons.
brooke@wolf.UUCP (Brooke Jarrett) (09/28/86)
Is there a Line Eater?
Is there anybody out there in net-land doing anything with Fractals?
I think they are just great to look at, ArtMatrix sells some nice postcards.
Let's have some response to this.
#include <std.disclaimer.h>
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Brooke L. Jarrett CliniComp Intl. (619)-588-4114
UUCP: ...!{sdcsvax,ihnp4}!jack!man!wolf!brooke 11022 Dutton Dr.
When asked if the game of Go was like life. He replied, La Mesa, Ca.
"No. Life is like Go." --- Japanese 9-dan 92041-7261
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