PopSci's Fourth Annual Brilliant 10

Doug James

Carnegie Mellon University

His programming prowess yields the fastest, most accurate collisions ever simulated.

A waterfall of plastic lawn chairs. A stampede of horses and elephants through chess pieces. A hail of fish smacking a bridge. These animations, created in hours instead of months, are the surreal handicraft of Doug James. "Everything I do has to have lots of cheap collisions," he says. James, 33, has created tools that simulate collisions more convincingly and faster than ever before. James hopes to enable programmers to manipulate 1,000 objects in the same amount of time it now takes to handle just one or two. That fluency could usher in novel applications that were formerly impractical, such as real-time virtual surgery; it should also enable more-realistic special effects in films and computer games, such as animated battles that look and sound natural.

When James started working on collisions in 2002, algorithms for simulating flexible objects were painfully intricate. The software divided each object's surface into many little triangles. When two objects touched, the program calculated the effects of the impact by determining the new locations of all the triangles. But James observed that the physics of collisions can be relatively simple. Bend a lawn chair, and only a small part of it moves. It shouldn't be necessary to model the entire object to create a realistic animation, he reasoned: "There should be an easier way to do things."

He capitalized on that hunch, using clever mathematics to describe colliding, flexible objects so that only the parts that touch require detailed calculations. By the old method, making a realistic deluge of 3,600 lawn chairs would take two months. James did it in 10 hours. Pixar, maker of the animated films Toy Story and The Incredibles, has given James some research money.

Moving almost as quickly as his animations, James is working on many new projects. He wants to simulate more-violent collisions and collisions that occur between complex objects such as animals. All of it has to be fast, fast, fast. "Speed up these fundamental things," he says, "and the sky's the limit."

-JR Minkel