Movie studios often want computer-generated hair to have a specific effect, whether it’s a seductive toss or a careless flick that knocks something over. But there’s a problem: most rough-cut simulations don’t realistically simulate hair, leading to a lot of guesswork and time-consuming edits. Disney (no stranger to hair-centric movies) has a solution, though. It developed a new system that can produce more authentic-looking simulations without an impractical boost to computation power. The trick, it turns out, was to use just a few cleverly controlled sample hairs. The team first extracted central “guide” hairs to use for complex simulations, with the remaining “detail” hair following suit under one main rule: the centers of mass for each subset of detail hair had to maintain their positions relative to dynamic reference points on the guide hairs. Read more
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