Full 2d and 3d L-Systems Node

[zeffii]

In the past i've implemented this in Javascript in d3.js (live demo here) but it's only 2d. There are various ways to implement L-systems and i've wanted to do a 3d L-system for some time now.

http://algorithmicbotany.org/papers/abop/abop.pdf second time reading this now. this time slower :)

[enzyme69]

L-Tree, something that I never got to master. Even there is this node in Houdini, this single node is so complex and required a class of itself.

Would like to see what you come up with.

The recursive and fractal business is often a headache for me.

[nortikin]

coool

[zeffii]

read all the code comments...and the only place you have to modify code is those two lines..

[nortikin]

a!!!

[nortikin]

i changed many parameters. never read instructions ))

[nortikin]

// variables
var bend = 2*(-35.5),                    // angle to twist (degrees)
    i_max = 8,                              // limit, warning 10 is probably an upperlimit
    i_user = Math.abs(Math.floor(7)),       // scrub between 1 and upperlimit for recursion levels
    iterations = Math.min(i_max, i_user),   // number of rewrites (recursion levels in grammar)
    F = 5890/(Math.pow(2.4,iterations)),    // arm distance
    angle_offset = to_rad(bend),            // angle as radian
    angle_rad = 0,                          // the current angle for drawing
    x_start = 351,                          // drawing start x
    y_start = 398,                          // drawing start y
    x_current = x_start,                    // current cursor position x
    y_current = y_start,                    // current cursor position y
    rules = {},                             // a map of the rules
    commands = {};                          // a map of the commands

[zeffii]

[zeffii]

already quite powerful, almost a direct port from the 2d .js code written by Jeff Steward and myself. ( https://groups.google.com/d/msg/tributary/9kI-CGVVQb4/J6joc8q6VhwJ ) https://github.com/nortikin/sverchok/blob/master/node_scripts/templates/zeffii/L-system_initial.py

[zeffii]

Next is pen up / pen down / store location / restore last stored location

[zeffii]

updated the SN script to have more meaningful inputs. https://www.dropbox.com/s/qiydtv162aoz6ny/fast_rerwier_lsystem2bender.blend modify the bend factor, you'll see some interesting shapes.

[zeffii]

Plans for the 3d implementation

It helps to think of the L-system as being 3d pen drawing with something akin to a 3d cursor to determine the point in 3d space.

• In down-mode the pen connects any new vertices added to the last added vertex.
• In up-mode the pen breaks the current 'polyline' to allow us to move to a new (or stored) location and then start drawing a new polyline.
• implement some default character grammar
  • [ is store current 3d pen position
  • ] return pen to stored 3d position
  • ( pen down
  • ) pen up
  • .. more to come.

because simple - and + are only good for 2d drawing, a different single character convention will have to work to place the pen at a new 3d vector, rotated relative to the last vector. Thinking in sparse

• Vector terms might help
  • X (x ,0, 0)
  • Y (0, y, 0)
  • Z (0, 0, z)

..still not fully settled on this

[ly29]

I'm looking forward to playing with this a lot.

[zeffii]

close for now. It's not super important anyway.

[zeffii]

https://cis700-procedural-graphics.github.io/files/lsystems_1_31_17.pdf

[enzyme69]

@zeffii Animation Nodes is having L-System node, I have not tested your node either. But awesome implementation from artistic and design perspective.

[nortikin]

@elfnor lsystem is GA_node.py That is it. use it, please

[nortikin]

pushing example json to master in shapes. Slao there is Elfnor's Generative art node, that represent kind of L-systems as i understand.