The Contenders: Visual-effects chief Joe Letteri on creating lifelike chimps

Four-time Oscar winner Joe Letteri is used to transporting viewers into strange new worlds in such films as “Avatar,” “King Kong” and the “Lord of the Rings” trilogy. The task was especially challenging in his latest film, “Rise of the Planet of the Apes,” the reboot of the classic 1968 science-fiction film based on French author Pierre Boulle’s 1963 novel. Letteri, senior visual effects supervisor at New Zealand-based Weta Digital, recently spoke to the Envelope about his work on the film during a break from working on Peter Jackson’s “The Hobbit.”

How did your work on “Rise” compare with “Avatar”?

We took the whole performance-capture technology that we built for “Avatar” and we integrated the characters into a live-action world. The biggest difference with “Avatar” was that the chimps don’t have any dialogue, so we were relying much more on the physical body language of the characters to tell their story in each shot.

PHOTOS: ‘Rise of the Planet of the Apes’ premiere

The apes in this film look extraordinarily real. How were you able to create that effect without using actual primates?

We spent a lot of time looking at and studying chimpanzees at the Wellington Zoo [in New Zealand]. They had a whole troop there, and we photographed them to understand what their skin and fur looks like. We also watched lots of nature videos to study how chimps behave when they walk or how they react when they are happy or sad. We set up a rehearsal space where actors could put on their motion-capture suits so they could watch their performances on a video screen in real time. It was a kind of digital mirror to see themselves as they appeared as chimps. We would play it back and analyze and say, “Let’s try this movement.” We built up a whole repertoire of moves going from a walk to a sit, running and lunging, until we had a library of things we might need.

It must have been a physically challenging task for the actors.

From an actor’s point of view, there are a whole lot of things you have to be aware of physically because of the differences between us and chimps. For one thing, they’re four-legged animals. We put our weight on our back legs. The actors really had to develop their arm muscles to be able to carry their weight on their arms as well as their legs. They had these arm extensions that looked like sawed-off crutches to extend their arms. That means their elbows and hands are in a different position than the chimps’, so we use computer animation to make adjustments and translate the human movement to the chimp’s movement.

What was the toughest scene to shoot?

The Golden Gate Bridge sequence, which we filmed on a 100-meter section of road on a backlot in Vancouver. The whole Bay Area and the entire bridge was digitally created and dropped into the roadbed, which was built to look like the five-lane highway on the Golden Gate Bridge. We used more than 100 motion-caption cameras in these little birdhouses.

How did you create such real-looking eyes for the chimps?

You really have to understand what these chimps were thinking because there was no dialogue, so the eyes were critical to that. We took four to six months to build a digital model of the human eye that was extremely detailed. You could see all the fibers going into the iris, to see how light bleeds into the eye, how veins are layered into the eye, and how the surface changes. We developed hundreds of algorithms to produce all the realistic motions of the eye. The micromovements of the eye can really make or break the realism of the character.

PHOTOS: ‘Rise of the Planet of the Apes’ premiere

richard.verrier@latimes.com