WETA’s VFX Lead Guy Williams on creating digital humans and crossing the Uncanny Valley with Gemini Man
Guy Williams is an Oscar-nominated VFX artist who has worked on The Avengers, Iron Man 3 and Guardians of the Galaxy Vol. 2. I was able to speak with him about his most recent work; Gemini Man, which is now yours to own in 4K Ultra HD, Blu Ray and DVD. In development since 1997, Gemini Man was finally able to come to fruition thanks to advances in digital animation. Gemini Man stars Will Smith as “an elite assassin, who is suddenly targeted and pursued by a mysterious young operative that seemingly can predict his every move.”
This young operative is a 20-year-old version of Smith’s character. Initially, I assumed that to create ‘Junior,’ WETA had used de-aging technology. Hollywood has frequently used de-aging tech recently with constantly improving results.
Take Samuel L. Jackson’s Nick Fury in Captain Marvel for example.
However, Guy Williams was quick to correct me. In Gemini Man, WETA didn’t de-age Will Smith, it built a completely digital version of him. To me, that was mind-blowing for a number of reasons. Firstly, WETA had managed to cross the Uncanny Valley and secondly, it had done so so convincingly that I thought I was looking at a real person.
If you’re unfamiliar with the term, Williams explains the Uncanny Valley.
A good way to give you an understanding is to say that we don’t have Uncanny Valley issues with animals. The human brain has spent millions of years evolving into something that understands other humans. We can see incredibly subtle variations in faces.
The Uncanny Valley is the stuff that we can’t quite put a finger on. Our brain doesn’t have to be able to do that. It doesn’t have to say his corner of the eye is one 10th of a millimetre too high, but it does have to say, ‘this is not a person.’ This is something that looks like a person, but I’m afraid of it.
Essentially, the Uncanny Valley is this nebulous, difficult to define phenomenon that causes humans to become uncomfortable in the presence of something that appears to be human, but isn’t
Williams goes on, “Our brains were attuned to understand expressions on faces and intent. It’s a survival instinct. If somebody is telling me that they’re going to take care of me, but they’ve got this weird look in their eyes, then I actually feel uncomfortable and want to get away from them.
“I don’t trust that they’re going to take care of me. Our brains have evolved to try to keep us alive. So when we start creating digital versions of ourselves, we’ve got millions of years of evolution to combat. We can’t just get it kind of good enough.”
Crossing the Uncanny Valley
One frequent culprit for causing Uncanny Valley issues is the eyes. Human eyes are incredibly difficult to create digitally and Williams says that something he calls “dolls eyes” is very tough to avoid.
“The fact that CG human’s eyes look kind of glassy simple gives us away,” Williams said. In order to get past this, Williams and his team dug into what makes an eye an eye. As he puts it;
Is it the eyeball? Is it the iris? Is the cornea, is it the corners of the eyes? Is it the eyelids? What is it about the eye that makes it look like a glass eye?
The more the team dug into it, the more the discovered, according to Williams. So they were able to gradually work on what was and wasn’t working until finally, they had an eye that looked like a real eye. I mentioned to Williams that there’s a scene in Gemini Man in which Junior is crying and that I specifically looked at the eyes during it to see if I could spot any digital trickery. I told him I couldn’t and that when I found out Junior was entirely digital, I was very impressed.
No More Doll’s Eyes
Williams explained that having gotten the eye ‘right,’ in the scene when he cries, the team “had to take it a step further.” He told me they had to “discover everything it means to become emotional.” By this, Williams wasn’t talking about animating emotions but rather, “just the mechanics of a human face.”
When you start to cry, your blood pressure goes up. It causes you to start to sweat and makes your face flush. You actually start getting redder in the face, which on African-American makes the skin go darker.
Your eyes start to get a little bit redder. The eyelids themselves become a lot redder. It’s not just a matter of squinting the eyes and putting a tear in there.
Fortunately, Williams and his team at WETA had plenty of reference material to work with. Smith performed all of his scenes as Junior while wearing motion and performance capture equipment so his performances were what drove the creation of Junior. In the crying scene, for example, Williams explains that “we could see how over the course of 12 shots in that scene, he went from having relatively dry skin and a certain shade of skin tone to being darker and more bloodshot.
“You could feel the stress. His eyes actually start to swell. We had to account for all of these things to make sure that, that our digital construct looked the same when he started crying.”
Something else WETA did differently when creating Junior was how it created skin. Rather than painting texture, the team created the skin by painting layers of pigment.
Take a Look in the Mirror
Williams told me that his shader team at WETA had discovered a better way to create digital skin. While painting a colour map for the skin and creating layers of pigment may sound similar, Williams said that by doing the latter, he was actually able to properly honour depth.
It also means that you get “view-dependant results.”
Instead of just having his skin be painted with a texture map that looks like Will Smith, we actually made it up out of melanin, pheomelanin, eumelanin, blood flow, all that kind of stuff.
So the result lookss like a texture map but as the head turns around, it changes the colours a little bit.
These are the tiny details that you won’t notice while watching Gemini Man, but your brain will. And by seeing these minute details, your brain can be tricked into believing that this digital human is in fact real.
Knowing that Junior was a digital character, rather than a de-aged version of Will Smith, I asked Williams if every time we see Junior we’re looking at a digital character.
“It’s probably half and half,” he said. While Junior’s face and head are always digital, sometimes his body is Will Smith’s actual body and sometimes it’s a digital construct. The reason being, the mantra was that the performance had to be Will Smith’s.
In scenes that have both young and old versions of the character, when filming, Victor Hugo would stand in for Junior. However, when the animation took place, WETA would erase his performance and replace it with a 100% digital actor.
However, when there’s only Junior on screen, Will Smith’s physical performance would be preserved and his hands and body would be retained. Then, everything from the neck up would be replaced.
I asked what reference material WETA used in order to create a young version of Will Smith and Williams told me he used “anything we could get our hands-on from before he turned 30.”
This meant watching Bad Boys three times, two seasons of The Fresh Prince of Bel-Air, Independence Day and Men In Black. Hearing that WETA watched old footage of Smith in order to create a young version of him in 2019 made me wonder if one day we’ll see digital actors replace humans.
Williams doesn’t think so.
“Junior cost more to put on screen than Will Smith. He’s not the cheapest guy to have in a movie but Junior is more expensive.”
It’s not just the cost either. Smith performed motion capture for the film and WETA “used his motion to drive a puppet.” So without human performance, these digital actors aren’t able to come to life. Finally, rendering characters of this detail takes a long time.
Williams said that rendering Junior took 300-400 hours per frame. Multiply that by the number of frames in the film and you’re looking at some serious time and processing power.
Even though digital actors aren’t likely to take over any time soon, watching Gemini Man gives a great indication of the current tech and the ability for talented VFX artists to create digital humans and cross the Uncanny Valley.
Thanks to Guy Williams for his time.
Gemini Man is now yours to own in 4K Ultra HD, Blu Ray and DVD