Issue link: https://digital.copcomm.com/i/42006
n n n n Motion Capture Given the tight schedule, the chimpanzee star, and the number of apes to animate, the crew at Weta Digital knew they wanted to use performance capture, a decision that worked out especially well once Serkis, who had played Gollum and Kong, agreed to perform Caesar. But, they also knew that although they could draw on some systems used in the past, the facility would need to develop new tech- nology, as well. "We wanted to take perfor- mance capture into the real world," says Dan Lemmon, visual effects supervisor. "There was so much interaction between the apes and the human actors, the idea of doing extensive on- set motion capture was a natural direction to try to go. To do that, we needed to deal with sunlight, hot set lighting, and have a system that was portable and flexible enough to adapt quickly and move with the production." Although Weta had experimented with on-location motion capture for The Lord of the Rings and had pushed the state of the art to capture the actors' performances on set for Avatar, the studio hadn't done on-location performance capture at the level required for this film. No one had. "We based a lot of what we did for this film on what we had done for Avatar," Letteri says. "On Avatar, our facial-capture technol- ogy moved from glued-on markers to the head rig." (The "head rig" is a helmet with a cam- era that records an actor's facial movements. A compact flash drive stores the recorded video.) Capturing facial movement for this film was important, too, but the apes communi- cate primarily through pantomime, so body capture was also critical. Thus, because chimps and humans are close in size—much closer than King Kong or Avatar's 10-foot-tall Na'vi, on-location performance capture made sense. "We knew we had to [create the apes] this way," Letteri says. "Rupert Wyatt knew about it. And, of course, we had done this before with Andrew Lesnie [cinematographer] for The Lord of the Rings. It was a good working team; everyone knew what needed to be done." On set, that meant the production crew worked with the Weta team to be sure they got all the data they needed. For its part, Weta tried to be quick. "We tried hard not to hold things up," Lemmon says. "And, everyone on set was pretty accommodating. The question was always, Do we hold things up for 10 min- utes or move on?" Bright Lights Prior to filming, Weta prepped all the actors who would be on set, fitting them with the head rigs and new capture suits containing active LEDs. "We didn't use optically reflec- tive markers," Letteri says. "We built LED suits. This was new technology for the on-set capture." Although the team had considered having actors wear specially marked suits, capture their performances on set with witness cam- eras, and convert the motion into data later by using optical tracking techniques, they felt that a direct motion-capture system would provide higher-fidelity data. But, the traditional motion-capture systems they had used for previous films were too bulky and cumbersome to have on set for an entire production. "The challenge was to boil motion capture down into a portable, flexible, lightweight sys- tem that we could reconfigure quickly," Lem- mon says. LED suits provided that solution. Moreover, "the LEDs weren't affected by At top, animators used keyframe animation for Caesar's fingers, which weren't motion-captured. At bottom, Weta captured the performances of as many as six actors at a time wearing head rigs and suits with LED markers, on location. 12 August/September 2011 the set lighting, and they worked in all kinds of situations—outside in sunlight, with light reflecting off cars," Letteri says. "We could phase the LEDs so the motion-picture camera couldn't see them and so we didn't have stray light bouncing into the camera." The system, built to Weta's specifications, included a control pack worn by the actor that communicated to a computer via an indus- trial-strength, long-reach Bluetooth transmit- ter. From the control pack, six strands of wires with attached LEDs stretched around the actor's body. Circling each LED was a colored marker. Four of the strands were Velcro'd onto the limbs, with one strand extending down each arm and leg. The other two ran down the front and back, with the head sharing the back strand. "It's an extension of a traditional optical motion-tracking system," Lemmon explains. "We used the cameras and pieces of software that we would use for a permanent capture