When Tom Hanks approached director Robert Zemeckis about turning Chris Van Allsburg’s 29-page book “The Polar Express” into an animated children’s feature, he couldn’t have known what he was letting himself in for. Not only was Hanks enlisted to play six different characters — including the young boy hero, the train conductor and Santa Claus — he had every inch of his face and his body motion-captured as he performed in a room no larger than 10 feet by 10 feet.
The ImageMotion process, designed by Sony Pictures Imageworks and Vicon, required Hanks to wear 200-plus markers that fed data into a computer via an array of motion capture cameras as he acted out his parts. Over the course of three years, visual effects supervisors Ken Ralston and Jerome Chen perfected the performance capture procedure that allowed Hanks’ acting to drive digital characters.
“Performance capture, for us, was putting a name on a highly refined version of what’s been done in the past,” says Ralston, referring to the now standard practice of motion capture that allows body movements to be convincingly recreated with ones and zeroes. “It was new in how much we were able to capture, especially the facial movements.”
Credit sophisticated digital camerawork, all done entirely within computer, for the movie’s live-action feel. “We created a system with no physical cameras at all,” explains Chen. “As he sees the digital characters (cinematographer) Robert Presley pans and tilts and follows their movement. He’s composing in real time as if it were real cameras and real actors.”
Another hurdle was making notoriously difficult textures such as hair and cloth look realistic and move convincingly.
“The breakthroughs were more in the amount of detail and minutiae that we had to do,” Ralston says. “The film is one giant morass of minutiae that had to be scrutinized and created as best as we could.”
It wasn’t so much about inventing things but harnessing the power of the computer to handle more data faster, and in a less roundabout way, he says. “What our guys were doing in software was trying to streamline it so we could get this monster through.”