- Brownian tree
A Brownian tree, whose name is derived from Robert Brown via
Brownian motion , is a form of computer art that was briefly popular in the 1990s, when home computers started to have sufficient power to simulateBrownian motion . Brownian trees are mathematical models of dendritic structures associated with the physical process known as diffusion-limited aggregation.A Brownian tree is built with these steps: first, a "seed" is placed somewhere on the screen. Then, a particle is placed in a random position of the screen, and moved randomly until it bumps against the seed. The particle is left there, and another particle is placed in a random position and moved, and so on.
The resulting tree can have many different shapes, depending on principally three factors:
* the seed position
* the initial particle position (anywhere on the screen, from a circle surrounding the seed, from the top of the screen, etc.)
* the moving algorithm (usually random, but for example a particle can be deleted if it goes too far from the seed, etc.)Particle color can change between iterations, giving interesting effects.
At the time of their popularity (helped by a
Scientific American article in the Amateur Scientist section), a common computer took hours, and even days, to generate a small tree. Today's (2003) computers can generate trees with tens of thousands of particles in a few minutes.These trees can also be grown easily in an electrodeposition cell, and are the direct result of
diffusion-limited aggregation .
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