• Andy Lomas

    Artist Profile, 26 March, 2006

    Pouring thru the CGSociety Vaults, we revisit research scientist, mathematician and CG Supervisor Andy Lomas. Moving from production to software research, Lomas continues his valuable knowledge to research KATANA at The Foundry.
    CGSociety :: Artist Profile
    Andy Lomas
    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.”
  • “I’ve tried color, but simple black and white diffuse light from all directions is the simplest, least biased way to show the forms,” he says. Also, the black and white forms reflect his respect for artist Ernst Haeckel, a biologist who used black and white woodcuts to render zoological forms that advanced his theories of evolution.

    To render his digital evolutionary forms, Lomas wrote software that can bounce light rays off more than 90 million metaballs in a complicated implicit surface. “I wanted to know how far I could push ray tracing. I’ve tried to make it as efficient as possible for implicit surfaces.”

    That efficiency is even more important now. Lomas was one of the last 12 people to leave ESC. He moved to DreamWorks as character effects head for the CGI feature 'Over the Hedge', then went back to Framestore. Since then he has worked on 'Avatar' as CG Supervisor, also 'The Tale of Despereaux' and joined The Foundry. “This is a bit of a switch from studio work to software, but it's been good so far.”

    “At The Foundry I'm leading the team working on Katana, taking Sony Imageworks' look development and lighting system and turning it into a new product for everyone else to use. Katana is a flexible, scalable framework for doing look dev and lighting using a node based 'recipe' approach. You can sort of think of it as Nuke for look dev and lighting. If you're interested in more details we're just published a white paper that I've written about it on our website.”

    On the art side of things, Andy has been pursuing personal creative ventures further when time and other responsibilities allow him. Following on from the Aggregation series, he's created a related series called 'Flow' based on visualizing the trail patterns formed when creating aggregation forms.
    “They're effectively a natural dual of the Aggregation pieces: the space where the form grows is left as a negative space in a sea of complex trails illustrating the flow patterns of the depositing particles.”

    I also had some work chosen by The Saatchi Gallery from a special exhibition as part of the Zoo Art Fair at the Royal Academy in London. Curators from Saatchi chose their favorite pieces from work submitted to Saatchi Online, with the work of 16 artist selected from the 60,000 submitted to the site. So I think that was quite a coup for digital art! It was also great to see the pieces up in the Royal Academy.”

    Although that scuba dive in Hawaii set his creative juices flowing, Lomas has been working on a rather different and more general system for simulating growth based on cellular structures. “It comes from a very different theoretical basis to the Aggregation and Flow series. Essentially you create forms by having regions of cell growth and death, with rules for things like chemical passing between cells which can determine what regions become new growth centres and the like. As well as the simulation system I'm also working on a new framework called 'Species Explorer' to help explore the complex multi-dimensional parameter space that the forms exist in.”

    “One of my main insights so far is that it's the edge case 'boundary zones' between different types of forms that are where the most interesting things happen, so that's one of the things the Species Explorer is designed to focus on.”

    “People seem to like the art, and I’d be a fool to say that I wouldn’t want to make a living doing this some day,” he says, “but I’ve got a family to support now. And, I like working on my own, but I also like working on teams. Our industry has lots of opportunities to work with good people on interesting projects and I enjoy that. The art is something I do for myself.”
    As a side interest, Andy has created his own art using these genetic algorithms and exhibited them in galleries in the Royal Academy as mentioned, but also in California as well as in Japan. This is not only a personal interest but a creative passion. Bridging the gap between the professional research and creative distraction. Many of Andy Lomas' images are also included in the Ballistic book, VESAGE, which showcase personal work from many of the professional members of the Visual Effects Society.

    Related links:
    Andy Lomas
    KATANA White Paper
    Visual Effects Society

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