PAL-System

Lindenmayer Systems allow one to specify a series of replacement rules for transforming strings.

If the text is used as a series of drawing commands, including saving and restoring the cursor’s position, the technique can generate fairly interesting foliage.

A scene graph offers the ability to save/restore by chaining segments together. I used Unity3D’s ScriptableObject to create “Languages” with replacement rules. I also created “Dictionaries” mapping symbols to segments made from GameObject prefabs. Finally, I explicitly marked a node in the segment as being the Leaf to which any successive stuff should be attached.

By allowing multiple overlapping rules, I let the system show a lot of variances. I added “Soar” mutilators to tweak the spawned things and show some more variance. By tweaking the “seed” value with the world position, I ended up with something that could use the same prefab to produce a whole forest of trees.

Overall I’m happy to move forward with this as a tool for filling in my own virtual forests. I think that it needs some work on the “usability” and could stand to take some lessons from Unity3D’s built-in tree system. Seems pretty good for a Saturday afternoon bit of messing about

Peter LaValle avatar
About Peter LaValle
honks at geese. speaks the byzantine languages that make the magic boxes do the things. Someday maybe I'll retire and be a graphics programmer or demoscene coder.
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