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I know there exists a lot of material on the procedural generation of plants and the like, especially using L-systems etc.

But after a quick research, I haven't been able to find any good / in-depth material on the structure of leaves. Specifically, though I've found a few articles on the shapes of leaves, but nothing on variegation.

Are there any good / in-depth resources on the realistic generation of leaf variegation?

I'm looking to be able to generate leaves such as in this image:

enter image description here

(I know this question might be pushing the boundaries of a good Stackoverflow question, but it is specific in the sense that a specific type of resource is asked for (variegation in leaves).)

Christophe Roussy
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Kelley van Evert
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For something emerging or constructural I would recommend cellular automata of many kinds. After a given amount of steps + some rules (constraints ...), interesting patterns that resemble natural ones can emerge.

https://pdfs.semanticscholar.org/c82a/8dd17ea8d6a0c35a82f573da51869cfb4bc4.pdf

Also see shells: https://tickblog.files.wordpress.com/2008/12/shell-automata.png?w=485&h=186

For leafs I think you could have a central symmetry + some rules concerning water propagation from the central stem with branching rules ... so maybe something between a cellular automata and graphs/l-systems ?

Christophe Roussy
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  • That's a clever idea. Probably has some correspondence to some of the actual properties that result in variegation. Repeat applications of the CA [b678/s345678 (aka the 4-5 rule)](http://www.roguebasin.com/index.php?title=Cellular_Automata_Method_for_Generating_Random_Cave-Like_Levels) might give a nice inner edge. Would probably need a different CA for the interior though. – Pikalek Mar 08 '18 at 18:53
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One way is to generate a mask & combine it with some noise. Here's a simple example that uses a distance from center mask:

enter image description here + enter image description here = enter image description here

Experimenting with these techniques, I was able to generate this leaf half:

enter image description here

This general technique is an easy & popular way make procedurally generated islands & searching for that term will bring up a number of tutorials. It may take a bit of tweaking to get the specific results you're after. For instance, my proof of concept doesn't account for interior leaf veins & my colors don't match the target. I made my mask by repeatedly blurring a black & white image of the leaf silhouette - I suspect a more sophisticated mask generation technique would give better results.

Pikalek
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