‘The Last of Us’: How the ‘Lord of the Rings’ VFX team (and marshmallows) made the Battle of Jackson

The Last of Us ended its first season on a high note. The finale, written by series cocreators Neil Druckmann and Craig Mazin, had the second-highest ratings among the first batch of episodes and proved that the cast and crew had done what was thought to be impossible.

They had successfully (and faithfully) adapted a video game.

Heading into Season 2, the Emmy-winning team behind the show, including the series' visual effect supervisor, Alex Wang, felt that they had proven their concept and were ready for something bigger. And on a show about surviving in a fungi-infested apocalypse, that means one thing.

More infected.

The VFX team had one big swarm under their belts — the infected's chaotic attack on a neighborhood cul-de-sac in Episode 5, "Endure and Survive." And for Season 2, there was only one direction in which to take things. "In the cul-de-sac, that was kind of the first glimpse of a horde of infected attacking, so we could get a sense of what we were capable of," Wang tells Gold Derby. "And Craig wanted to be bigger, and he wanted to really extend out in terms of scope for Season 2."

What Mazin had in mind was something big and loud for the second episode, "Through the Valley," to counterbalance the gruesomely intimate drama playing out between Pedro Pascal's Joel and Kaitlyn Dever's Abby up at lodge.

The solution Mazin came up with was a battle, embellishing a skirmish present in the game into something epic.

And, to the eyes of Wang, epicly difficult. "When all the department heads read the script for Episode 2, we were gobsmacked," he recalls. "How were we going to pull this off? I mean, we were all like, 'No, this is, this is impossible. Guys, like, what? What are we doing here?'"

But, as anyone who watched "Through the Valley" (and has the trauma to prove it) can attest, The Last of Us did indeed pull it off. And Gold Derby spoke with the team involved to find out just how they managed to do it.

Battles are hard

So why exactly did Wang's eyeballs nearly fall out of his head when he read the script for Episode 2? The goal of most visual effects shots is for the work to disappear and for the image that's being created to come to life. A battle sequence, especially one with hundreds of CGI characters, provides visual effects artists hundreds of opportunities to break the illusion.

"Digital humans in this day and age are still difficult, especially when you're putting up a digital creature right next to a real person, because the question is not just, 'Does it look photoreal?'" Wang says. "Clearly we try to achieve that — and I hope we did — but also their movement. Performance is almost more important than how they look."

The right allies are important

And while the scripts alone were ambitious, Mazin's visual reference for the Battle of Jackson wasn't going to make the sequence any easier. "Craig definitely wanted his Two Towers," Wang says.

If the visual effects team from The Last of Us was going to be able to evoke Helm's Deep for the proposed Battle of Jackson, Wang knew that there was one company better equipped than any other to take on the challenge: Weta FX.

Director Peter Jackson founded the company, alongside Richard Taylor and Jamie Selkirk, and for The Lord of the Rings, the company pioneered technology that brought realistic, massive computer-generated simulated armies to the big screen for the first time, winning multiple Oscars along the way. Weta FX had done some work on Season 1 of The Last of Us, but the Battle of Jackson was going to test even the company's very experienced artists.

An army of infected is more complicated than the forces of Mordor

Weta FX's Dennis Yoo, the animation supervisor on The Last of Us, originally moved to New Zealand, where he now lives, to work on The Return of the King. And he was able to explain how the old elves-versus-orcs tricks weren't going to work on the Battle of Jackson's recently thawed horde.

The crowds running down the Wyoming mountainside couldn't be uniform like an army. They couldn't be all the same age. They couldn't wear the same clothes. And perhaps most importantly, they wouldn't move with military precision. "They're falling over each other," Yoo says. "They're tripping. They're pushing each other, and then there's this grander scale where it's almost like watching a huge mass of people reacting to different things."

Clothes make the horde

But even if the army of infected is moving right, they've got to look right too. Nick Epstein, the visual effects supervisor at Weta FX, and his team created a system to populate the digital throng with unique infected, based on scans of 30 stunt people in full prosthetics.

Off of those bases, the team could add detail through a mix and match system that assigned specific hairstyles, wardrobe, and level of cordycep growth to each individual, resulting in a diverse mass.

'Blazing sunshine was definitely the worst.'

There's a major upside to staging a set piece like the Battle of Winterfell in the blackest of nights: It's harder to see detail. That wouldn't be the case with the Battle of Jackson, which would take place in daylight, albeit with some cover provided by a winter storm.

"One of the only saving graces was that it was in the middle of a storm," Epstein says. "You'd have some visibility fall off at a certain point. But that doesn't help you with everything that's super close to camera. There's nowhere to hide at all. Blazing sunshine was definitely the worst."

Fire makes everything more complicated

One of the first lines of defense for the people of Jackson, led by Gabriel Luna's Tommy Miller, are barrels of gasoline, which are shot and then lit aflame, sending the infected up with them. "Craig wanted performance changes, right?" Wang says. "The infected had to react to the fire, so here's a whole other type of mocap and animation from the animators that they had to consider."

But dying creates even more issues

As the dead became deader and the corpses of the infected piled up outside the gates of Jackson, the visual effects team needs to account for what happens to those mounds, which are more logically complicated than you might imagine, or as Epstein describes them, his "biggest nightmare."

Each pile of bodies wasn't one digital mass, but a collection of models, subject to ragdoll physics, which would fall on top of each other and then require their own simulated cloth to keep their clothing realistically moving. Multiply that 500 corpses, and it becomes easier to understand Epstein's struggle.

Tomatoes are best for bloaters

For Tommy's 1-v-1 showdown with a bloater, Wang led his department on a journey to find the right visual reference for what it looks like when a massive mutated cordycep walks straight into a flamethrower. "We spent months doing research and trying physical burning of different materials, just to see what bubbling characteristics we wanted to include," Wang says.

The team incinerated marshmallows and found macro photography YouTube videos of burning plastic, but ultimately found their favorite material in the produce section. "Tomato is actually one of the best things, because the skin would start to ripple and bubble and break apart," Wang says. "Then inside, there's all this juicy goodness that we wanted to match to. And it's basically what the skin of it represents, the skin of the bloater, because it had a hard shell, almost like armor."

The hardest episodes can be the most rewarding

To a person, every visual effects artist who spoke with Gold Derby about the making of the Battle of Jackson agreed that it was the biggest challenge of their career. And each one of them reflected on the chaos they were able to render with genuine pride.

"It was daunting to read the script," Wang says. "But everyone just wanted to give the script what it was calling for every single step."

"This was just gnarly in terms of asset development, gnarly in terms of weather control, gnarly in terms of integration of our computer graphics with the plate," Epstein says. "It was really hard, really challenging, but also really rewarding, too."