My entries: 3 L-systems

[eNZedBlue]

Click on links to enlarge.

"Bric-a-brac":

http://i19.photobucket.com/albums/b199/Stormfronter/Bric-a-brac.jpg

"Eightways":

http://i19.photobucket.com/albums/b199/Stormfronter/Eightways.jpg

"Phi Phractal":

http://i19.photobucket.com/albums/b199/Stormfronter/PhiPhractal.jpg

The first two are plane-filling at infinity.

[Sockratease]

That Third one, "Phi Phractal", is Wonderful!

And you got some great repeating patterns in the other two as well.

Nice Work!

[lycium]

bric-a-brac exhibits startling complexity, i'd be interested to know which l-system features were used in its creation!

as usual, your technical mastery of fractal art shines through

btw, the reason i ask is because my l-system fractals are invariably quite primitive (technically):

http://www.deviantart.com/deviation/14863738/ (it's the hdr rendering that makes this look good)
http://www.mysticgd.com/thomas/slinkyspace/sunlitjunk.png (it's the global illumination lighting that makes this look good)
http://www.mysticgd.com/thomas/slinkyspace/chunkytree.jpg (again with the gi lighting)

the last image is about the best looking result i've managed to coax out of l-systems, the system was made by evolving random l-system strings via batche renders until something vaguely decent came out. i then cheated and made the l-system context sensitive (ie the rotation will try to avoid nearby objects based on 1000 or so proximity ray-cast tests - very slow!). but anyway the point i'm making is that you seem to "get" l-systems, intuitively understand how to make good looking results with them - i have to employ all sorts of lighting tricks to get good results if you've any pointers to share about making good l-systems i'd greatly appreciate it!

btw, some basic executables from my 2nd year uni project used to make those images: http://www.mysticgd.com/thomas/old%20lsys+rtview.zip (and there's more stuff at http://www.mysticgd.com/thomas/slinkyspace/)

[eNZedBlue]

Sockratease & lycium,

Thanks for the feedback. 

bric-a-brac exhibits startling complexity, i'd be interested to know which l-system features were used in its creation!

Basically I use a rule where I take a circle defined by a centre and a radius, then subdivide it into sectors by computing points on the circle at intervals of 360/n degrees (where n is the number of child circles on the circumference, 4 in this case), then draw n "spokes" from the centre to the edge of the circle and create child circles using the points on the circumference and the parent radius multiplied by some scaling factor. I also recurse in the centre, using the parent's centre-point and a new radius calculated using a different scale factor. For added variety I rotate each generation by 360/2 * n, and link up the child centre-points (or mid-points between them) using lines to create a polygon with n sides. I'm going to do a page on these L-system with diagrams etc illustrating the rules graphically and put it on my site sooner or later (it makes much more intuitive sense in graphical form). It's quite fun figuring out which scaling/rotation constants to use to make them plane-fill for any given value of n. So far I can make it work for n = 3,4,6 and 8, and also for 5 and 7 with a bit of chicanery.

http://www.deviantart.com/deviation/14863738/ (it's the hdr rendering that makes this look good)
http://www.mysticgd.com/thomas/slinkyspace/sunlitjunk.png (it's the global illumination lighting that makes this look good)
http://www.mysticgd.com/thomas/slinkyspace/chunkytree.jpg (again with the gi lighting)

Looks good! I'll check out your tools.

if you've any pointers to share about making good l-systems i'd greatly appreciate it!

A couple of tricks I've picked up:

- For any L-system fractal you can do a circle (or sphere) inversion transformation on all the lines to produce arc segments for a related fractal.
- Fade out the brightness of the lines used for each generation
- If animating and L-system then apply a 3*3 box filter over any fractal rendered using vector graphics or else it looks noisy as hell when you scale/rotate it.
- For ideas/inspiration I use esoteric/mystical symbolism, since a lot of it has nice geometrical properties, for example the "seed of life" and "flower of life" sacred geometry patterns, as well as pentagrams, swastikas, merkabas etc etc. Traditional Islamic art and Hindu & Buddhist mandalas are also full of cool patterns that often has a "fractally" look to it.

Here is a simple OGL app I wrote for displaying these (and other) L-systems using an infinite zoom animation using 4 1024*1024 textures:

http://www.enzedblue.com/Fractals/Apps/HypnotronOGL.zip

Press 1,2,3,4,5,6,7,8,9,0,Q,W,E,R,T,Y,U,I,O,P,A,S on the keyboard to display the different fractals. Some time I'm going to get around to adding a text-file with options and stuff.

[lycium]

Looks good! I'll check out your tools.

wow, calling my hardcoded stuff "tools" is far more generous than i could possibly hope for! ;P although the l-system itself isn't hardcoded the rendering options are, and in order to achieve realtime ray tracing with that horribly inefficient "engine" of yore i had to switch off the global illumination. you can still tune the antialiasing settings though - the r key maximises it and +/- adjusts it iirc.

If animating and L-system then apply a 3*3 box filter over any fractal rendered using vector graphics or else it looks noisy as hell when you scale/rotate it.

that implies a lack of antialiasing, which a low quality blur will definitely not fix since you're using opengl, you should be able to go into your driver settings and just flip the antialiasing switch. that's boxfiltered antialiasing unfortunately, but the 16x mode available on my 8800 looks very good already; for best results i recommend rendering at a multiple of the final resolution then doing a hq resize in irfanview using one of the better filters.

Here is a simple OGL app I wrote for displaying these (and other) L-systems using an infinite zoom animation using 4 1024*1024 textures:

man, i'd really love to check that out right now but the sorry state of nvidia's 64 bit drivers for my new gpu prevent me from doing so i don't have a 32bit os installed at the moment, and my laptop is pretty much out of the question graphics-wise... i've downloaded it though and will definitely check it asap. i've detailed these woes in a recent thread here: http://www.fractalforums.com/index.php?topic=386.0