Digital fantasy brought to life
Hollywood magic isn’t just about eye-popping special effects. Paul Debevec knows a thing or two about those: He earned a Scientific and Engineering Academy Award for his digital animation work on Avatar and more recently contributed to The Avengers, which is nominated for an Oscar in visual effects this year.
But for a presentation on his work at “GLIMPSE: A Digital Technology Showcase,” an exhibition of USC’s digital media prowess, Debevec showed off a lower-key demonstration that was just as impressive. He played video of an actress displaying a range of different facial expressions and moods. No explosions, no fantasy creatures — just video of an entirely digital creation, indistinguishable from the real thing.
Debevec, associate director of graphics research at the USC Institute for Creative Technologies, has been making his mark in the field of digital animation since the 1990s. And chances are you’ve seen some of his work.
In 1997, the computer scientist directed a short film allowing viewers to fly over a photo-realistic version of the Campanile at the University of California, Berkeley. This virtual cinematography caught the eye of John Gaeta, visual effects supervisor for The Matrix and ultimately helped develop the movie’s iconic “bullet-time” sequences.
What he’s best known for, however, is his work with digital capture technology systems known as Light Stages. Appropriately, these stages look the part for a technology that helps Hollywood create blockbuster moments.
Picture a geodesic sphere filled with lighted bulbs. Actors climb inside and are photographed from 360 degrees, capturing a wide range of expressions and movements. The vast array of data these stages can capture provides “an alphabet of anything [the actor’s] face can do,” Debevec said.
They can capture and modify different layers as well — including the specular reflection created from light bouncing off the sheen of oils on an actor’s face. Controlling these reflections are a crucial part of making digital animation convincing, and the Light Stage animations have the distinction of crossing the uncanny valley, the point at which the human eye can tell a recreated human being from the real thing. Debevec said when he first showed the actress in the demonstration her digital self, it was convincing enough to fool her.
As digital effects have become more widely used in film, this kind of technology has found new applications. There are obvious ways to use it, such as in The Curious Case of Benjamin Button, where Brad Pitt’s face is artificially aged using effects that earned the film an Academy Award. But there are more subtle ways as well.
The blue-faced Na’vi are the standout animations in Avatar. But considering that many of the environments are digitally rendered, Debevec said, it makes more sense for many scenes to use digital recreations of the human actors rather than filming and inserting them separately. Few, if any, viewers could tell if lead actor Sam Worthington is real or not when he’s lying on the jungle floor or when Stephen Lang’s villainous character is encased in a robotic mech.
Even less fanciful Hollywood fare has made use of this technique. In The Social Network, the Winklevoss twins were played by actor Armie Hammer and a stand-in, Josh Pence. Hammer’s face was digitally inserted over Pence’s — though watching a scene where “the twins” speak to each other in close-up while rowing a boat, you certainly wouldn’t know it.
These may be the most obvious uses of Light Stage technology, but Debevec has just started to scratch the surface. Partnering with the USC Shoah Foundation: The Institute for Visual History and Education, Debevec and his colleagues are capturing full-body data of Holocaust survivors. These time-intensive shoots are conducted as lengthy interviews — survivors are asked about their experiences, their thoughts on the existence of God and other questions in several different ways. The idea is that schoolchildren will be able to view and even interact with holographic versions of the survivors, preserving their memories and experiences for future generations.
“We want to give as much as we possibly can to give these kids a sense of who these people were,” Debevec said.
Holograms are another research interest for Debevec. Along with virtual reality expert Mark Bolas, associate director of the Institute for Creative Technologies, he’s experimenting with holographic teleconferencing. During the GLIMPSE presentation, he played a video showing researchers speaking to a lifelike head and face created by dozens of handheld pico projectors. Walk around the hologram and you can see the person’s head from 180 degrees.
Debevec has spent much of his career making digital fantasy come to life on movie screens. But with the trajectory of his latest work, it seems yesterday’s blockbuster technology is set to become an everyday feature of tomorrow.