it is 2016 and Brad Pitt's latest heist film, Ocean's Fifteen, is a roaring box-office success. Moviegoers can't get enough of his wit, charm and ever-youthful good looks - except the man himself never set foot in front of a camera. Instead, Pitt's digital image was recreated on screen by teams of visual effects artists, leaving the actor free to work on other projects.
This scenario is quite plausible. Motion-capture technology has created realistic non-humans, such as Gollum in The Lord of the Rings and the Na'vi in Avatar. Now the time has come for a digital human to be cast in a leading role.
"We're definitely there, it just needs to be exploited," says Stephen Rosenbaum, a visual effects supervisor who won an Oscar in 2010 for his work on Avatar. "You look at the imagery and the performances and it's absolutely believable. It just takes a director that's going to be brave enough to cross that line."
Some directors have already come close. Shortly after winning his Oscar, Rosenbaum joined Digital Domain, the Los Angeles visual effects company behind two of the most believable examples of a digital human. In The Curious Case of Benjamin Button, released in 2008, they transformed Brad Pitt into an old man who then grew younger throughout the film. In 2010 they did the reverse, allowing Jeff Bridges to play a younger version of himself in Tron: Legacy.
Bridges wore a headset attached to four cameras that tracked his facial movements, which were then mapped onto a digital model of his younger self. The model was created by scanning his head and face and altering their appearance based on images and video from his earlier films.
With motion capture it is possible for the head and body to be played by different actors. Pitt and Bridges's characters used older and younger body doubles so that their body movements were right for the character's age.
"Benjamin Button made a huge leap in look, but benefited from the fact they had an older character," says Ben Morris, Oscar-winner and visual effects supervisor at the Framestore studio in London. Button's advanced age meant he didn't always have to be fully expressive. A younger Bridges proved more difficult. Morris says: "I think it was incredibly impressive, but I felt on occasion the character's eyes and facial animation didn't work."
