Hi Friends,
I'm looking for a new Inkscape feature to learn, and the Effect > Modify Path > Fractalize sounds interesting. I've read the Tavmjong Bah guide, which explains the settings in the dialog, but doesn't answer my question.

As I understand fractals, they are inherently symmetrical in certain ways. They aren't 100% symmetrical, or really even close, but it's usually easy to identify symmetrical portions. But after a fairly lot of trial and error with the dialog, I havne't managed to create anything even remotely symmetrical.

Have I got the wrong idea about the Inkscape Fractalize Effect feature? Is it not intended to create fractal drawings from selected paths?

Thanks for your help

I'm also a bit confused by the title of this effect, I think maybe the author ment to say Fragmentize?...

I found Tavs guide quite useful:

This effect turns a straight-line segment into a crooked segment. It works by finding the midpoint of the line segment, adding a node at that point, and then moving the node a random distance perpendicular to the original path direction. This division routine is called recursively ...

I can understand why it's called Fractalize - because the same procedure is being applied over and over again on the resulting segments, but the key why it doesn't look nice and symmetrical as you'd expect is because the amounts of movement are random and not according to a nice symmetrical formula. That's why you get a raggedy edge and it's very useful in many situations.

This effect isn't the tool to draw nice fractals, your best bet is Effects > Render > L-system
http://tavmjong.free.fr/INKSCAPE/MANUAL ... indenmayer
http://www.inkscape.org/screenshots/gal ... nmayer.png

I played with that effect a lot, I spent a long time trying to find the right L-formula for a very specific fern-like leaf structure. What kind of fractals would you like to draw? Just one hint - don't use high number of generations, 3 will give you the basic idea, 5 can take a long time to draw if the formula is long and complex (some of my masochistic creations took 20 minutes to calculate).

Well yes, I read that in Tavmjong's guide, but it didn't answer my question (Why is nothing symmetrical?) Although, to be fair, I don't understand what "This division routine is called recursively..." means.

Since posting this topic, I have found the L-System thing, but one needs to understand some kind of mathematics that is beyond my ability. I did find this:
http://www.inkscape.org/screenshots/gal ... nmayer.png
which gives settings for several fractals. But I was wanting to be able to create my own, new and different drawings, like the Spirograph Effect does. I've tried to play around with the settings, but they are not intuitive. I haven't the slightest idea what an L formula is

What kind of fractals would you like to draw?

I don't have anything particular in mind. I just thought this feature could create symmetrical fractals, and that I could play around with the settings to make all different kinds.

Thanks for your help, prkos

Do you, or does anyone know of a program or tool with which one can create their own fractal drawings, without having to know advanced math?

FYI, my search so far has yielded several, found on this Wikipedia page:
http://en.wikipedia.org/wiki/Fractal_ge ... g_software
as well as:
Chaoscope at http://www.btinternet.com/~ndesprez/index.htm
I haven't looked closely at each one, but can't wait to! Still interested in referrals if anyone has experience with this, though.

All best

[Edit] OMG, I'll never be the same! I've discovered a whole nother world of computer graphics!

[2nd Edit] Another list of fractal software:
http://home.att.net/~Paul.N.Lee/Fractal ... l#FractInt

brynn wrote:Well yes, I read that in Tavmjong's guide, but it didn't answer my question (Why is nothing symmetrical?) Although, to be fair, I don't understand what "This division routine is called recursively..." means.

It's not symmetrical because the formula for node displacement is random, they are not always moved in the same direction and by the same amount. Recursive means that you take a formula and apply it to itself over and over again (or something like that). I'll explain it bellow.

brynn wrote:Since posting this topic, I have found the L-System thing, but one needs to understand some kind of mathematics that is beyond my ability. I did find this:
http://www.inkscape.org/screenshots/gal ... nmayer.png
which gives settings for several fractals. But I was wanting to be able to create my own, new and different drawings, like the Spirograph Effect does. I've tried to play around with the settings, but they are not intuitive. I haven't the slightest idea what an L formula is

It's more of a grammar than maths. It resembles an old computer drawing game Turtles, some kids still learn about it today. You have a turtle that you can order where to move, as she moves she leaves a trail, if you are careful of the moves you can make a meaningful drawing.
L-systems are like controlling the turtle moves, you just have to learn the syntax. If you type a certain letter the turtle will move forward and leave a trail behind (straight line). If you add the same letter after the first one the turtle will make another trail in the same direction. If you use another letter the turtle will move but will not leave a trail (letters are mapped in the Inkscape script, you can see which on the Help tab of the effect dialogue).

If you put a + in front of a letter the turtle will turn right and then make the step, with or without the trail. - is for turning left. You can adjust the turning angle in the dialogue too.

The only thing left to explain are square brackets; lets say you're drawing a tree, you make the trunk steps and then turn to make the first branch, you draw the branch and want to be immediately returned to the trunk so you don't have to trace the same steps back along the branch - put the first bracket before turning to the branch and the second one after you reach the last step of the branch. The second bracket will know where to return and what direction to take.

Here's an example:
F=F+F-F
Set the order to 1 and the angle to 90 and see what you get, it should be easy to understand how that drawing came from F+F-F. Then set the order to 2 you will see the result is bigger.

What happens in the second order is that the formula is applied once more, the expression F+F-F is substituted in place of F everywhere in the formula so you get F=(F)+(F)-(F)=(F+F-F)+(F+F-F)-(F+F-F). The brackets here are just to visually group the elements so you see how generations change (order.)
So the actual formula for the second generation is F=F+F-F+F+F-F-F+F-F
The third order (generation) formula has much more letters in it!

Here is an example of a tree formula:
F=A[+F]A[-F]AF

Use the angle 25 and compare generations 1 and 2.
A is a step that doesn't change through generations, and F does, F gets substituted by the formula it is defined with.

brynn wrote:Do you, or does anyone know of a program or tool with which one can create their own fractal drawings, without having to know advanced math?

I only know of the linux ones, they usually draw the famous fractals (Mandelbrot, Koch flakes), I never figured out how to try out my own formulas there. They let you define color gradients to use to get those nice colorful drawings.

Thanks for all that great info, prkos. I really appreciate it.

Since my last message, I've found several freeware, and even an open source fractal drawing program. I've started to play around with them some, but so far haven't learned enough to be very successful. In none of them does one need to know math. Countless formulas are offered as unique files, and you can play around with the various settings to make nice abstract art. Once I figure out how to get them into a png or gif or jpg, I'll post a sample. I'm looking forwards to using them to create other images. Although they appear to be better suited for raster type graphics programs.

Thanks again prkos

I can't wait to see your fractal art

I can't wait to see your fractal art

I just posted several in the Off Topic forum [link].