Painting in the digital medium of ones and zeroes, today's visual effects artists can conjure almost anything imaginable. For decades, though, one particular creature has remained stubbornly just out of their reach _ and it happens to be the one they see in the mirror every day.
In the visual effects community, creating a completely believable, photorealistic digital human being, capable of holding its own alongside flesh-and-blood actors for an entire film, has long been considered the holy grail. Films like "The Curious Case of Benjamin Button" and "Blade Runner 2049" have moved the industry toward that goal in recent years, with varying degrees of success. Now director Ang Lee is making the boldest _ and riskiest _ effort yet with the sci-fi action film "Gemini Man," which pits the 50-year-old Will Smith, as a government hit man, against a 23-year-old version of himself.
For more than two years, Lee and some 500 visual effects artists have been working virtually nonstop to try to pull off a convincing facsimile of one of the world's biggest movie stars as we haven't seen him since he first burst on the scene more than 25 years ago. And until the film hits theaters on Oct. 11, they won't be sure if they have pulled it off.
"From the start, I said, 'This will be harder than we can imagine,'" Lee says. "Every shot is going to be under scrutiny. That's really scary. I'm still scared."
The idea for "Gemini Man," in which aging assassin Henry is hunted by a younger clone, had been bouncing around Hollywood since the mid-1990s, waiting for technology to catch up with the concept. In early 2017, producer David Ellison, whose Skydance Media had acquired the project from Disney, pitched it to Lee.
Having created the CGI hero of 2003's "Hulk" and a digital tiger for "Life of Pi," the two-time Oscar winner was instantly intrigued by the technological challenge.
"We are creating from whole cloth a fully digital human," says visual effects supervisor Bill Westenhofer, who shared an Oscar for his work on " Life of Pi."
That requires grasping the concept of the "uncanny valley," a phenomenon identified by a Japanese robotics professor in 1970 to explain why a not-quite-perfect imitation of a human is so unnerving.
"There's so much subtlety in expression; you can tell if someone is mad at you or happy with you," says Weta visual effects supervisor Guy Williams. "If you create a digital human and you don't get 100% of that nuance in there, your brain instantly starts to throw red flags."
Before production even began, Williams' team at Weta began the process of building the clone, dubbed Junior, referencing images and footage of Smith's early film and TV work. They also pored over the minutiae of the human face: the various types of melanin in the skin and how they interact with light, different layers of the eyeball, fine details of tooth enamel.
During production, the film was essentially shot twice, once on an actual set with Smith playing Henry opposite a stand-in and then a second time on a performance-capture stage, with Smith, wearing a body suit and facial camera, now playing Junior. Weta's visual effects artists then collected the data and brought it together with the work they'd done digitally modeling the younger Smith to flesh out Junior.
Still, for all the high-tech wizardry brought to bear, the character remains firmly rooted in Smith's performance. "Will had to get all of the nuances in the difference between his 50-year-old self and his 23-year-old self," says Westenhofer.
For everyone involved _ from the executives at Paramount, which is releasing the film, on down _ making "Gemini Man" was a major leap of faith. There was simply no way to know whether this high-wire walk across the uncanny valley would work until it was too late to turn back.
"You could imagine what it may be like, but there was no example [to] visualize it," Lee says. "Your heart is pounding for a year and a half, and then one day you see one of the shots and it's really exciting. Then you still worry about the other 500 ... It just takes one shot to take you out of the movie."
