CGSociety :: Artist Profile
by Barbara Robertson
Eight gallery exhibitions in one year would be a remarkable accomplishment for any artist, but for a digital artist, it’s especially impressive. Meet Andy Lomas, an exceptional artist who has done just that.
Lomas’ black and white “Aggregation” stills are on their way home from his latest exhibition during the Media Arts Festival at the Tokyo Metropolitan Museum of Photography. These still images show complex sculptural forms that he generates with his custom simulation and rendering software; his “Aggregation” animations show the forms in process. The forms are as intricate and intriguing as something found in nature even though each was born inside a computer.
First published in Ballistic Publishing’s VESAGE, the “Aggregation” stills and animations have now traveled to the Butler Institute of American Art in Youngstown, Ohio, the Computing Commons Art Gallery at Arizona State University, the Los Angeles Center for Digital Art, and SIGGRAPH.
|Although long interested in art forms created with genetic algorithms, Lomas began working on the software for “Aggregation” some years ago. “I was scuba diving in Hawaii,” he says, “and seeing corals and other beautiful natural things underwater. That was the inspiration. I began thinking about how simple a rule could be to generate a complex form.” The inspiration for the rule came from a base algorithm called “diffusion limited aggregation” invented by physicists T.A. Witten and L.M. Sander in 1981. “It’s essentially a random fractal generator,” says Lomas. “A simple physics environment for a digitally simulated growth process.”|
The process is simple. It starts with an immobile seed particle placed in the center of a circle. Then, a new particle called a walker is launched. The walker moves randomly until it hits the edge of the circle or the seed particle. If the walker hits the edge of the circle, it disappears. If it hits the seed, it’s frozen and becomes part of an “aggregate” seed. One after another, walker particles are launched and deposited into an ever-growing aggregate. As the aggregate grows, it forms into a familiar kind of branching fractal pattern.
|He explains that the environment lends itself to modifying, adjusting and biasing the physics rules to affect the way aggregated shapes grow. “This, and the extreme simplicity of the basic algorithm are two of the main things that appealed to me,” he says. “So, in my spare time, I tried variations of the algorithms. And, I made the forms much more complex by using millions of particles rather than thousands of particles.”|
”Most of his “Aggregations” contain around 50 million particles although some include 96 million. He grows the forms inside virtual cylinders by placing the original seed at the bottom, releasing walker particles at the top, and sculpting the evolving shapes with forces - gravity, vortices, and so forth – that influence the way the walkers move and create asymmetries.
“Small biases produce big changes in the final structure,” he says. “What you get is a system that accumulates growth, but the growth is affected in the same way a tree is impacted by elements over the years.” When the accumulation grows into a shape Lomas likes, he stops the simulation and renders the form using black and white ambient occlusion rendering.
|“For The Matrix Reloaded, Jay Reynolds used a simple 2D version of the diffusion limited algorithm to produce an extra organic level for the black goop that swarmed over peoples’ faces when Agent Smith punched them,” says Lomas. “I created a variant on that aggregation.” Lomas was a CGI supervisor for The Matrix Revolutions and worked on color and lighting for The Matrix Reloaded. After the Matrix films, he became ESC’s studio-wide head of computer graphics charged with revamping the pipeline.|
“It was less insane at ESC once the Matrix films were done,” he says, “and for a while, I had the luxury of having a lot of machines on the render farm. Reynold’s work started me thinking about ways to take the diffusion limited algorithm, move it into 3D, twist it and apply different biases to it.”