How Gemini Man's VFX whiz made two versions of Will Smith

"It was about creating the memories we have of Will," says Weta Digital's Stuart Adcock, who explains Smith's digitally de-aged dual role.

Sean Keane Former Senior Writer
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Sean Keane
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Will Smith faces his younger self in Gemini Man.

Paramount Pictures

The new action movie Gemini Man gives us a Will Smith double-whammy. Smith plays an assassin coming face to face with himself -- a younger version who's out to kill his older self and take his place.

The thriller, directed by Ang Lee, is in theaters now. The younger Smith was created with the VFX -- or visual effects -- wizardry of Weta Digital, a company co-founded by Lord of the Rings director Peter Jackson. Beyond Middle-earth, Weta conjured effects for Avatar, Game of Thrones, Ad Astra, the Planet of the Apes series and the  Marvel Cinematic Universe . With Gemini Man about to land in theaters, I spoke to Stuart Adcock, Weta's head of facial motion, about how the company set up the battle between 51-year-old Smith and his 23-year-old CG self.

Digital de-aging is everywhere thanks to movies like Captain Marvel and The Irishman. How is Gemini Man different?
Adcock: We had Will playing against himself. We leaned on performance capture for that, so we would have Will playing an A-B scenario. We'd have Will playing Henry and wrestling with a stand-in and so forth. There was really nowhere to hide behind smoke-and-mirrors visual effects. 

And then we would flip the equation, and this time, Will played Junior. We put a head-capture rig on him with two small cameras looking at his face to capture his performance. Then in post-production, we used performance capture to really understand the performance he gave. So we could 100% re-create synthetically a fully digital 23-year-old version of Will Smith. 

Did you use any older Will Smith films and TV shows as reference?
The era we were focusing on was around the Bad Boys period [1995, when Smith was 27]. Independence Day was another one that we looked at. One of the challenges is that throughout all of these, Will had a goatee beard, and Ang wanted to make sure Junior was clean shaven to help differentiate the two characters. That meant we had to work harder in all the other aspects of Junior to make sure there was a likeness of Will without the goatee. 

That really became part of the challenge of the whole project. This wasn't about just creating an authentic human, it was about creating the memories we have of Will.


Director Ang Lee and Will Smith on the set of Gemini Man.

Ben Rosenstein

Did you draw on The Fresh Prince of Bel-Air, which aired from 1990 to 1996 and featured a clean-shaven Smith?
We had very little reference from Fresh Prince, actually. But there was a phase in the project where it did prove useful, when we were trying to land on a good base shape for the proportion of Will's face. We looked at a lot of scientific research of how faces age over time, and we got some really young images of Will from when he was 8 years old and some of the really young Fresh Prince to try to model the appearance of his face from that period. 

Did you have to create a proof of concept of the de-aging technology?
We set ourselves a challenge, which was to re-create a couple of shots from Bad Boys to try to create a digital version of Will. We turned that over to Ang quite early on in the production. We had a lot of fun with that; we were hiding some of the subjects within the footage and letting people look at it, not realizing that what they're looking at was completely digital. As soon as we started fooling people internally, we realized this is possible.

How does this movie advance de-aging tech?
I think through this journey, we've learned so much about the human face and how eyes need to be represented. … Often it's the eyes that let a shot down. 

We developed a technology called Deep Shapes which allowed our animators to essentially change the reading of an expression from deep facial layer to the top-level epidermis layer. So they're able to condition the shape through the layers of the skin, which allowed us to get these nonlinear patterns in the eyes and in the lips.

The concept for Gemini Man has been around for more than 20 years, and a whole bunch of actors -- Harrison Ford, Chris O'Donnell, Mel Gibson, Jon Voight, Nicolas Cage, Clint Eastwood and Sean Connery -- have been attached to the role. Why is Will Smith the man to bring it to life?
He gave everything to this role -- he went above and beyond to play both parts. Taking one asset so it plays on a younger or older version is one part of the equation that we do at Weta, but it stems from an actor who's able to give us a convincing, compelling performance to hinge that on. I think that really marks how successful it would be.

I'm sure that's why Ang Lee thought "Will's my man," because he's just a completely professional, dedicated actor who is so charismatic and so dedicated to his craft that just to see his work on this film and the energy he brought to it …  I think that's the real success.

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Originally published Oct. 7.