L-System

This page documents the development version of Graphite at dev.graphite.art, which may differ from the current release.

Grows a string by rewriting all of its symbols at once with the rules, once per generation, for drawing with the Turtle Path node.

Since every symbol with a rule is replaced in each generation, patterns repeat inside themselves at ever finer scales, like the branching of plants or the folds of fractal curves.

Interface

Inputs

Parameter	Details	Possible Types
Axiom	The string to start growing from. Primary Input	`String[]` `String`
Rules	One rule per line, like `F = F+F-F-F+F` (or `F -> F+F-F-F+F`), which replaces every `F` with `F+F-F-F+F` in each generation. Symbols without a rule stay as they are. A rule can also check the symbols around one, as in `A < B > C = D`, which rewrites a `B` only between an `A` and a `C`. A rule ending with a chance from 0 to 1, like `F = F[+F]F : 0.6`, applies only that often and otherwise leaves the symbol as it is. The chances of a symbol's rules can add up to 1 at most. Symbols can carry numbers, like `F(10)`. A rule names them to work out new numbers with math, and to apply only when the condition after `:` holds, as in `F(x) : x > 2 = F(x/2)[+F(x/2)]`. A chance can be worked out from them too. A `%` cuts off the rest of its branch, up to the `]` that ends it. Lines starting with `//` are skipped. Default: `F = F+F-F-F+F`	`String[]` `String`
Ignored Symbols	Symbols to look past when a rule checks the symbols around one, usually the turns between them. Listing `[` and `]` reads the string straight through its branches, as if it had no brackets. Default: `+-`	`String[]` `String`
Generations	How many times the rules rewrite the whole string. Each generation can multiply its length. Default: `3`	`Integer[]` `Integer`
Seed	Seed to determine unique variations on where the rules with chances apply. Default: `0`	`Integer[]` `Integer`
Max Symbols	The longest the string may grow, in symbols, and the most generations that run. A generation past either is left out, guarding against a number of generations that would freeze the editor. Default: `1_000_000`	`Integer[]` `Integer`

Outputs

Product Details Possible Types

Result

Product	Details	Possible Types
Result	The value produced by the node operation. Primary Output	`String` `String[]`

The value produced by the node operation.

Primary Output

String
String[]