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Wētā FX Helps Bring the Infected to Life - and Death - in ‘The Last of Us’ Season 2

VFX Supervisor Nick Epstein and Animation Supervisor Dennis Yoo talk previs, massive hordes of real and CG infected, an ‘ant hive’ of frozen infected, digital dogs, and an even bigger bloater they helped produce for HBO’s critically acclaimed and wildly popular series.

When it came time to return to the fungal-infected wastelands of HBO’s Emmy Award-winning The Last of Us for its highly anticipated second season, Wētā FX found itself facing a host of new challenges. The bar had already been set with the studio’s horde scenes and creature animation on Season 1. But with an epic battle in Episode 2, including a full-scale siege of town of Jackson, swarms of infected, and the introduction of a new bloater, the visual effects demands expanded significantly.

Visual Effects Supervisor Nick Epstein and Animation Supervisor Dennis Yoo led Wētā’s contributions to the show, joining the production early to help shape the massive action sequences that anchor the season. “We started with previs,” Epstein explains. “We had some script pages from Craig [Mazin], and the battle was absolutely epic. There was a need to visualize that early on.” With Michael Cozens serving as the previs supervisor, the team worked closely with the show’s filmmakers to block action across a fully built, four-block set representing the town of Jackson.

“You’ve heard about the set they build for Jackson,” he continues. “A fully realized town with all these buildings that were fully functional inside. Our job was to figure out, ‘Where’s the action taking place? Where are the best camera placements?”

As Epstein describes it, the process was highly iterative. “They’d have a new edit that would be viewed on set with the director Mark Mylod, Craig, and the DOP. We’d take their notes, turn around another edit, and eventually we arrived at something they were happy to shoot with.” The previs served not only to help plan the shoot but later became part of the editorial cut, creating a strange moment of realization for Yoo. “Sometimes we’d see our previs back in the edit,” he says. “It’s actually more scary to see it come back. You’re like, okay, we have to do it for real now.”

The centerpiece of Season 2’s visual effects is a chaotic siege on Jackson that unfolds across a sprawling set under volatile weather conditions. “The weather changed every day,” Epstein recalls. “You’d arrive, it’d be blazing sunshine, suddenly it’d pour with rain. A storm blows through the middle of Episode 2, so we had to conform everything to that weather pattern.”

The scene required an immense infected horde, with some shots needing up to 300 infected on screen. While the production had 30–40 stunt performers in prosthetics, Wētā was responsible for expanding that number significantly using CG. Epstein emphasizes the importance of always grounding the visual effects in some form of reality, noting, “I loved the way the filmmakers approached the show. Even if a shot was going to end up being full CG, they would shoot something. There’d be a plate for it. It gives you a level of realism that sets the bar, both for CG infected moving like the stunt actors, and the environments. Sometimes though, they required some inhuman movement that humans can’t quite perform. Dangerous things, like slamming into a wall, or a dog biting someone’s throat. So, we obviously had to create that.”

Yoo adds that Season 2’s animation complexity increased substantially. “In Season 1, we had shots where nine infected ran into the dark. That was fairly easy. In Season 2, the horde needed to be organic. You had hundreds of people pushing into each other and interacting.” One of the key challenges was making the movement feel natural — something Yoo notes Mazin was particularly attuned to. “He was like, that looks like a bunch of people running a marathon, not wanting to touch each other.”

To achieve the right look, Wētā used a layered approach to animation. “Each shot was a layering process,” Yoo explains. “There’s motion capture, keyframe animation, and simulation. The simulation grounds everything in physics, but there’s no artistry in that. So, you have to animate what you have. Re-simulating just causes other problems.”

“You can’t have stunt people or motion capture people jump on each other and hurt each other,” he continues. “You’re laying motion on top of plates, then going into lighting, into FX. It’s a huge layering process.”

According to Epstein, “The infected are running through the snow. Great. That means we have to simulate the snow. They’re bumping into each other and falling on the ground. The ones that have fallen have to influence the ones running behind them. You can’t just steamroll past. So, the bodies eventually pile up, which you have to take into account with the CG simulations. How are those bodies going to influence the rest of the horde?”

That complexity extended to crowd variation. “We’d scan the stunt actors and end up with perfect duplicates,” Epstein says. “It’s not interesting. So, we went through a process to figure out how to vary them, how far to push the level of infection.” This meant matchmoving heads, adding digital cordyceps infections, retouching skin textures, and peppering in more advanced infection stages. “The prosthetics team did a fantastic job, but we had to push it further,” he adds.

Season 1’s prosthetic-heavy approach — over 100 infected stunt performers — proved difficult to augment in post, leading to changes this year. “They learned from Season 1,” says Yoo. “They did more prosthetics in Season 1, but if it doesn’t look right, it’s hard to remove. This time they went with level-zero infected so we could add more in CG.”

Being present on set helped the Wētā team understand the constraints. “The stunt horde and makeup teams would start at 2:30 in the morning,” Epstein recalls. “Putting prosthetics on 100 people daily is a huge job.”

Wētā's digital characters needed to stand up next to the prosthetic performers. “It makes almost every shot like a Pepsi challenge,” says Epstein. “You’re seeing a full-screen stunt actor right next to a CG infected. They have to match.” According to Yoo, “Every one of our infected could hold up really close to the camera.” Epstein adds, “We had a crowd of hero characters. Everyone was fully cloth and hair simulated.”

Among the most difficult sequences was a pivotal moment where the infected burst from beneath the snow. “The way Craig described it, it was like an ant hive,” Epstein says. “You’ve got this mesh of frozen bodies descending and frenzied live ones crawling out over them. That shot went right to the end. We used up all the time we could get, right up to the last day.” “We were dropping bodies in a pit that wasn’t even fully realized, then animating motion through those bodies, climbing on top of them, with snow and storm simulations on top,” Yoo elaborates.

Another challenge was animating dogs. “Everyone knows what a dog moves like,” Yoo says. “Everyone knows what the fur looks like. If you get it wrong, people know. Especially when you’re keyframing the whole thing — jumping, attacking. It’s difficult. We were watching a lot of real dog attacks to get it right.”

One of the biggest set pieces involved the return of the bloater, the towering, fungus-covered infected seen in Season 1. “The idea was, what else can we throw at Jackson?” Epstein says. “You hear the bloater’s roar through the storm, and Tommy knows what that is. It’s gone from bad to worse.”

This season’s bloater was redesigned to be more threatening and to reflect its appearance in broad daylight. “He was about 10% bigger,” Epstein notes. “We had no place to hide. The lighting was not forgiving.” Motion-wise, they brought back Ike, the same performer from Season 1. “Craig immediately recognized his performance,” Yoo says. “There were little nuances he brought. It helped to ground the animation.”

One shot — a slow camera pullback as the bloater charges — required a full-CG build. “We had a plate, but we just had to redesign the shot,” Epstein says. “It needed to be his big entrance.”

Looking back, both supervisors are proud of their work and grateful for the opportunity to be part of the adaptation. “I was a big fan of the second game,” Epstein says. “To be part of that — it’s been really cool.” Yoo agrees, sharing, “Huge fan of the games, both of them. Super appreciative to be part of both seasons.”

With HBO already planning a third season and more game content to adapt, it’s likely Wētā FX will once again return to the infected world of The Last of Us. And judging by their work so far, they’ll be ready.

Dan Sarto's picture

Dan Sarto is Publisher and Editor-in-Chief of Animation World Network.