Fractal Tree Library with Bezier Curves

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# 2D Fractal Tree Library This library generates 2D objects that can be exported as SVG files. It does not produce a valid three-dimensional object that can be printed. ## tl;dr: * `trunk();` * F6 (render) * Export as an SVG in OpenSCAD: `File > Export > Export as SVG` ## Thanks All Bezier Functions based on the excellent work of @caterpillar [Justin SDK](https://www.thingiverse.com/JustinSDK/about) https://openhome.cc/eGossip/OpenSCAD/BezierCurve.html Thanks to SteveWeber314 for his fractal tree tutorials https://www.thingiverse.com/steveweber314/about The latest version of this can be found at github: https://github.com/txoof/fractal_tree ## Licenses Released under GPL v3 - Share Alike Please see the included LICENSE file for the complete license text. ## README This library uses pseudo-random Bezier curves to generate a 2D vector drawing of a tree. There are many parameters that can be adjusted to produce different trees. To use this within another OpenSCAD design, try: use </Path/To/This/File/bezier_tree.scad> trunk(); Here are three examples, all grown from the same "seed" but with tweaks to the parameters to produce three very different trees. To produce a tree similar to a birch tree (thin, tall, quickly diminishing, and straight), try the following settings: trunk(size = 900, bend = 25, seed = 40, depth = 12, widthBottom = 100, widthTop = 90, maxAngle = 45, minAngle = 35, branchProb = [40, 20, 10], maxGrowth = .9, minGrowth = .9, decay = .85); To produce a tree similar to a gnarled old oak (thick, branching horizontally, with a bushy crown), try the following settings: trunk(size = 600, bend = 150, seed = 40, widthBottom = 300, widthTop = 90, maxAngle = 60, minAngle = 30, branchProb = [50, 30], maxGrowth = .8, minGrowth = .5, decay = .9); To produce a tree similar to a palm tree (tall and slender), try the following settings: trunk(size = 1200, bend = 10, seed = 20, depth = 15, widthBottom = 50, widthTop = 30, maxAngle = 90, minAngle = 45, branchProb = [70, 20], maxGrowth = .7, minGrowth = .3, decay = .8); ### Design Considerations To create more bent branches, increase the bend/size ratio. size = 500, bend = 250 will make a VERY twisted tree. Setting depth above 9 can result in very long execution times as the recursion grows exponentially with depth. ### Parameters module trunk() Parameters: Denotes parameter that is used internally by recursion and is not intended to be used from the initial module call (suggested values in parentheses) size [real] size of first segment (linear from origin) seed [real] seed with which to generate a pseudo-random tree depth [integer] recursion level (1 to 8) widthBottom [real] maximum width at base of trunk widthTop [real] maximum width at top of first trunk segment minGrowth [real] minimum amount to grow the new branch (0.1 to 1.2) maxGrowth [real] maximum amount to grow the new branch (0.1 to 1.2) decay [real] base amount to diminish each branch by (0.5 to 1.2) minAngle [real] minimum angle to rotate each branch (0 to 180) maxAngle [real] maximum angle to rotate each branch (0 to 180) branchProb [vector] % chance of one, two or three branches occurring [%one, %two] ([10, 40]) - %three is calculated as the remainder of 100-%one-%two. In this case, %50. step [real] step size to use when generating Bezier curves values approaching 0 are smoother, but take much longer to render (0.05) *depthMax [integer] records maximum depth on first call *distance [integer] records distance from "trunk" - can be used to diminish branches *start [vector] records [x, y, z] vector at which to start *first [boolean] first run sets persistent variables for recursion growing the branch debug [boolean] turn on debugging including control points