The Special Effects of Benjamin Button

At the Academy Awards last week, the Oscar for visual effects went to the team behind The Curious Case of Benjamin Button. The movie was a special-effects success thanks, in part, to a company called MOVA and its novel motion-capture system.

Motion-capture systems track actors’ movements and allow those movements to be animated using computer-generated characters. The technology has come a long way in the past decade, but many of the systems used for movie making require a human actor to wear hundreds of reflectors, so they are limited to sensing large movements of the body, not subtle details in a facial expression.

However, MOVA’s technology, employed in Benjamin Button along with other technologies, uses a glow-in-the-dark powder that can reveal tiny details like laugh lines or a furrowed brow. In a studio, MOVA’s system uses an array of cameras to film an actor’s facial expressions while the lighting alternates between light and dark at a rate of 100 times per second. The video is then sent to a computer where the glow-in-the-dark tracking points on the actor’s face are used to create a three-dimensional digital version of her face. Because the powder can’t be used in the eyes and mouth, digital engineers add them afterward.