The latest Homing Beacon has arrived, and today we get to talk CG hair. It wasn't entirely by accident that most of the computer-generated characters from Episode I had smooth amphibious skin or hard metal finishes. When it comes to unmanageable hair, the digital variety has the most kinks to work out. The workload of Episode I favored hairless subjects, as did Episode II, though the digital creations in Attack of the Clones did feature a few exceptions: Yoda had a hazy crown of wispy white hair, and the digital doubles of the main characters had to be as stylishly coiffed as the actors who played them.

"With the digital doubles, you have less hair than you would a furry creature, but it has to be specific hair," says Steve Sullivan, Research and Development Director from ILM. "You're actually trying to match a given actor, so the artist needs to be very precise in the parameters."

Some of the Industrial Light & Magic's early experimentations with digital hair were with creatures in Jumanji and The Flintstones. Just getting a computer to recreate the thousands of individual strands was a milestone, but teaching it how to move was a different challenge altogether.

"For the lion in Jumanji, it was very complicated to have something as dense as a mane. There is no way an individual artist could control all the hairs directly, so they went with an approach with 'hero hairs' or 'guide hairs.' An artist would animate those and place them carefully, and then the computer would generate all the stuff in between. So, the hair colors, densities, lengths and so on were generated by the computer, but very much controlled by the person. These hairs didn't react at all to the environment or the motion of the lion, so somebody had to animate them by hand," says Sullivan.

The proper interaction of the hair with the underlying digital model is now handled by dynamic physics simulation, the same complex computations used to properly recreate the folds and drape of digital clothing and the hundreds of fragments of crashing Podracers. Now, the digital hair reacts as it would to real wind, gravity, and motion, without having to be continually managed by an animator. Still, the task is not that easy.

"The current approach is like this: say you wanted to comb your hair," explains Sullivan. "You'd look in the mirror, turn off the light, try and comb it, wait a few hours, turn on the light again, and see how it looks. It's very indirect and very painful, and that's what the artists who do this kind of work have to deal with. We have a long way to go still, and our mission is to try and make it as simple as possible. You can imagine what a hair system should be like. It should be easy. Your mom should be able to use one of these systems, but it's going to be years till we get to that stage."