How 'Furious 7' brought the late Paul Walker back to life

A version of this story first appeared in the Dec. 18 issue of The Hollywood Reporter magazine. To receive the magazine, click here to subscribe.

In the pre-digital era, Paul Walker's death on Nov. 30, 2013, would have made finishing a movie like Furious 7 a daunting task. Since several of his key scenes had not yet been filmed, recasting and reshoots would have been necessary. But digital filmmaking techniques have changed all that. While Universal was mum about exactly how Walker's scenes were finished when the movie, which went on to gross $1.7 billion worldwide, was released in April, now that it is a serious candidate for visual effects awards consideration, VFX supervisor Joe Letteri, from Peter Jackson's Weta Digital, is explaining exactly how they did it.

Because "we didn't have everything you would have wanted from a reference and research perspective, when Universal and the filmmakers regrouped and decided they did want to finish the film and the Paul Walker story, we thought at most we could get one scene of a digital Paul that maybe had some dialogue in it, and we'd have to find other ways to finish the story," says Letteri.

The general process: 1. Caleb Walker performs the scene. 2. Unused footage of Paul Walker in a similar shot, filmed at night. 3. Weta adjusts the lighting. 4. Caleb's head is replaced with Paul's in the final shot; Courtesy of NBC Universal

But then Walker's two brothers, Caleb and Cody, stepped forward, and, says Letteri, "allowed us to scan them and work with them in the scenes, it really gave us something as close to Paul as we could hope for. That got us a long way toward being able to create a realistic character and performance. Then we started to work on: What does the story really want to be, and can we do it? The scope of the work bloomed so we could tell the story and finish the character arc."

In the end, roughly 260 shots -; like shots following the car jump between Abu Dhabi's Etihad Towers -; involved performances by one of the two brothers, whose own faces were replaced by CG versions of Paul's. "We didn't do CG costumes and bodies because the brothers were close enough," Letteri says. In other scenes, a third actor, John Brotherton, also stood in for Paul.

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An additional 90 or so shots were completed with outtakes or older footage of Walker that had already been shot and which were then relit and repurposed -; such as the shots of Walker driving in a car alongside Vin Diesel in the film's closing moments.

To create the CG head replacement for Walker, Weta started by scanning the brothers as the closest reference. "Then we used Paul's footage for the final touch up to his model" to capture details like skin textures," Letteri explains. To animate the simulated performance, the VFX vet says "we used a lot of Paul's footage as reference, because as close as the brothers were in style and mannerisms, they just weren't Paul when Paul played his character. We really tried to limit our interpretation of the character to things that we had seen Paul do as the character. We found performances that matched the situation that we needed to put him in, and we used that to guide us."

The final element that had to be added was dialogue. "Most of the CG shots had some kind of dialogue," Letteri says. "The sound editors had to craft the vocal performance out of [existing] dialog from Paul, and we had to animate to that."

With any CG human, the key challenge is sidestepping a perceptual zone known as the "uncanny valley"-; when a virtual character is close to looking believably human, but still isn't quite right, the results can look creepy. Letteri says avoiding that was all in the details: "You'd see small changes in the corners of his mouth that would telegraph what he was thinking, or in the corners of the eyes. These are really small details, but if you get them wrong, you feel that there something fake about the performance. Other details involved placing the stubble on his beard correctly -; the length and placement of every individual hair -; because when that was off, it didn't feel like Paul."

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Hollywood has used various VFX techniques in similar situations before -; in Gladiator, when Oliver Reed suffered a fatal heart attack during filming, and on HBO's The Sopranos, to complete scenes of the late Nancy Marchand, who played Tony Soprano's mother. But the work on Furious 7, which convincingly returned Walker to the screen, showsjust how sophisticated Hollywood can get with enough time, money, and, critically, talented VFX artists.

Sums up Letteri: "There really wasn't room to let anything slip. It was too important to complete the story in respect to Paul's memory -; to make sure that when you watched it, you didn't think about any of the work that we did. If you were a fan, you were watching Paul's performance and saying goodbye."

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