Question - AVS Forums

Nanakiwurkz

16th May 2006 22:54 UTC

Question
Whats the best way to make a c curve fractal, sierpenski curves,sierpenski triangle fractal, mandlebrot fractal,Julia fractal. any suggestions. i'm trying to make a few for my new pack i'm currently working on. any suggestions are open.

PAK-9

17th May 2006 09:52 UTC

1) Add superscope
2) Enter equation
3) ????
4) Profit!

Fractals are pretty simple you just have to sit down and code the iterative loop (I would use evallib to nicen the loop coding). I dont personally think they make very good presets though, since the end result is basically a picture. They are, however, a pretty good way to do something technical that shows you can code... not that I care about that sort of thing or anything.

Nanakiwurkz

17th May 2006 23:55 UTC

thanks
one question pak whats a loop?
and whats evallib?
and i need to know do you have any more avs tuts then the programming guide?

jheriko

18th May 2006 00:39 UTC

Re: thanks

Originally posted by Nanakiwurkz
one question pak whats a loop?
and whats evallib?
and i need to know do you have any more avs tuts then the programming guide?

1) it lets you run the same piece of code over and over:

// a slow way to set a to 1000
a=0;
loop(1000,assign(a,a+1));

2) evallib is the programming language used for avs code

3) http://tutorials.jheriko.kicks-ass.net/ nothing about evallib but some useful stuff for raytracing and 3d cameras

Nanakiwurkz

18th May 2006 00:45 UTC

thanks alot Jheriko.

PAK-9

18th May 2006 08:49 UTC

sorry I meant eeltrans (AVSTrans) not evallib

ASD5A

18th May 2006 15:08 UTC

before you ask: eeltrans also known as avstrans is a .ape that
makes coding much easier, especially if youre messing with (g)megabuf and loops.

Nanakiwurkz

18th May 2006 22:32 UTC

a big question is to Jheriko. is it possible to use your gvm tool to create fractals?

PAK-9

19th May 2006 00:05 UTC

http://img243.imageshack.us/img243/4243/idiot9ui.jpg

jheriko

22nd May 2006 03:10 UTC

Originally posted by Nanakiwurkz
a big question is to Jheriko. is it possible to use your gvm tool to create fractals?

Well, if you want a static fractal you could generate an image and store it in the megabuf then use that to draw it.. it wouldnt be fast though.

You need to approach the problem more logically I think. First find a fractal you wish to render. Secondly, find an algorithm or algorithms for generating it.

Most fractals come in one of three basic types as far as rendering is concerned (excuse my made up terms):

Continuous: e.g. mandelbrot/julia fractals. These are potentially the most expensive to generate since you need to iterate per sample on some 1d/2d/3d line/grid/volume to work out the colour at that point.

Constructive: e.g. dragon curve, pythagoras tree. These are probably the easiest and cheapest to render since they are simply collections of lines/triangles where each iteration adds more lines/triangles to the shape, but doesnt change the existing ones

Subdividing: e.g. Koch snowflake. The Koch snowflake can be constructive if we use triangles, but if we want to find the border curve we must take 3 lines to start with (triangle edges) and replace each line with 4 new lines per iteration. Since we have to throw away the old geometry for each iteration these fractals are slightly more expensive than the simpler, constructive sort.

If your fractal is continuous I would recommend going and finding something else, unless you notice a convienient hack (see the varying DM julia set presets).

The constructive sort are quite easy to render as long as you understand the algorithm involved, you typically just need to create a superscope/triangle renderer which mimicks the algorithm for drawing the fractal.

The subdividing sort are a bit more complicated, and you would invariably need to use megabuf to get a reasonable iteration count.

Ultimately though, you want to learn how to render points, lines and triangles before attempting anything this complicated :P

Hope this helped...