‘Avatar: The Way of Water’ VFX Artists on Creating Realistic Water in a CG World

When Avatar first came out in 2009, it used cutting-edge VFX technology to bring the jungle world of Pandora to life. The alien flora and fauna and the indigenous 10-foot-tall blue-skinned Na’vi looked so real. Even more so when watching it in 3D. More than a decade later, director James Cameron gives audiences a reason to revisit Pandora with the highly anticipated sequel Avatar: The Way of Water. The sequel explores new territories and utilizes newer natural elements like water. The latter of which has never been done before.

(L-R): Lo’ak and a tulkun in 20th Century Studios’ AVATAR: THE WAY OF WATER. Photo courtesy of 20th Century Studios. © 2022 20th Century Studios. All Rights Reserved.

But water and VFX technology has always been a part of Cameron’s visual storytelling. Whether that’s how we made the liquid metal antagonist T-1000 look so terrifying or how he recreated the destruction of the Titanic, the director has always pushed the limits on mixing water with cinematic technology.

“For me, the most exciting part was the It’s a new world, you know, there is the Pandora world that we’re familiar with. But this was so many new places we’re exploring,” said Pavani Boddapati. As one of the VFX supervisors, Boddapati is responsible for bringing the Metkayina Village and reefs to life. And that cinematic exploration through the characters and audiences’ eyes is what excited her the most about making the movie. “I think it’s almost like the world building the excitement that you would have felt watching this movie and seeing all these new places, that was really, really exciting.”

And since Avatar: The Way of Water spends a lot of time, well, in the water, it only makes sense that the cast and crew are tasked with making it look natural by researching the element. “It’s definitely made taking tropical vacations or even just your weekends walking on the beach — you spent a lot of time sitting there staring at the water going, ‘ours’ doesn’t quite look like that,” said Jonathan Nixon.

As FX supervisor, Nixon oversaw how the fire and water visuals interacted with its environment, including the characters that populated the world and how it would relate to its surroundings. So he would look at the different foam patterns or how bubbles grouped together and what that would look like under different lighting. “The thing that’s interesting about water is that I think you can find references to match almost anything because a lot of it has to do with wind patterns and storms.”

“Specifically living in New Zealand, it’s hard not to drive to work and just kind of slowly look and go, ‘Oh, that’s interesting. Let me pull over, take some images, take some footage, and I think our artists did a lot of that,’” Nixon continued. “Our artists did a really good job of understanding if it doesn’t work in reality, it’s not going to work in this film. And so that’s where it needs to start.”

Eventually, the two would have conversations with Cameron about figuring out the landscape and how the real-life tropical topography would influence the look and feel of the Metkayina Village. They learned how the blowhole connected the tide pools and the outside sea. And that when the waves crashed against it, it would force the water to come out of the blowhole.

So the crew flew down to some of the neighboring tropical islands like Bora Bora but also had to use the footage that had already been shot before during the pandemic. “As an effects artist, you’re always looking for new references. Whether you’re just watching a YouTube video, you’re watching something on television, he’s referenced for just everything, just visually, you’re just looking going, ‘oh, that’s interesting,’” Nixon said. “And then you just start to research into that area and see, okay, where, you know, what’s the difference between the Atlantic Ocean and the Pacific Ocean based on currents and heat. All of those things come into play just for the look. And I think that’s what, that’s what we spent a lot of time doing.”

“We also have a research team at WETA effects. And one of the first things we did back five, six years ago, is we have this researcher who was working with a rendering team and our shader team to figure out the water shader,” Boddapati said. “This water shader cannot look like Wellington water and cannot look like New Zealand water. It needs to look like tropical water. And Bora Bora is probably the closest. That’s what we were looking at for color and for depth because it matched sort of the size and scale of the Metkayina.”

“So there was a research component where there were papers that were read. And our water shader is composed of finding the exact composition of water, particularly the sand color from tropical countries,” Boddapati added. “And this is all scientific information. So, the groundwork and the foundation of some of this stuff is not just visual reference. What we shoot is also scientific measured reference that is, you know, open sources, someone’s gone and written a paper. So the research team is a huge component of this.”

(L-R): Ronal (Kate Winslet), Tonowari (Cliff Curtis), and the Metkayina clan in 20th Century Studios’ AVATAR: THE WAY OF WATER. Photo courtesy of 20th Century Studios. © 2022 20th Century Studios. All Rights Reserved.

But the research and referencing for Avatar: The Way of Water didn’t stop at water. Fire also has a dual purpose in this film. Whether that’s in heating or lighting or in massive destruction. And Nixon’s process to capture the different sizes and scales of fire started very small. “So it’s always about scale. We’ve got the big large, sort of explosions and big destruction fires at the end of the film. But we also have things like you said, very simple of cooking, or torch or something very small, and being able to sort of hit those different scales,” he said.

And the fire research started very small. “So we actually did a very first test of like a candle, and what happens with the candle and how fast is the candle moves, and what’s the oscillation speed and how many beats is it. Based on the air and things that are around it. And then we took one candle and combined two more candles to it, and you start with three candles, and what happens is the flame grows a bit more,” Nixon added. “So we started really basic and then moved into flame bars and things that you would see on set.”

“Our goal is always just to match that reference. If we can match the very simple reference from a simulation standpoint, it translates very well to then scaling things up to adding more forces and more fields and things into that to make the big explosions to make the big, you know, sea dragon, you know, explosions and sea dragon fire at the end that’s burning,” Nixon continued. “I think from the math on that standpoint, it really is just trying to get the oscillation and specifically sort of what happens when something combusts. What is that process? A lot of that has to do with starving oxygen and what happens when you starve oxygen Things start to grow. And so it’s that type of process that I think allows for us to make it look as real. We start with reality and then build off of that reality to see where that creative process takes us.”

“We tended to get really good capture on the water and really good capture above water. The interface between water and air is both a tricky thing to capture accurately and a tricky thing to animate,” said senior animation supervisor Dan Barret. “In terms of Kiri underwater, so much of that was was performance captured, done in the tank. We just couldn’t have done this film. Without that, you know, that those performances taking place underwater.”

The tank itself was so huge that it could create different types of currents, whether it’s giant waves or something similar to a lazy river, depending on what the scene calls for.

And shooting above and below water also presented challenges for the other animators who worked in the lighting department. “What it turned out to be is relatively simple, which is two discrete volumes that sit one above the water below one that eliminates the light spectrum from one bleeding into the other. And we shoot one in IR and one in UV. And I put them directly on top of each other temporally and geographically aligned output to a tertiary system,” said Richie Baneham, visual effects supervisor at Lightstorm. “That’s, that’s what gives us our visual and in real-time, and we have to make it as safe as possible for our actors, obviously. So egress is a big thing in water.”

(L-R, Front to Back): Zoe Saldana, Sam Worthington, Kate Winslet, and Cliff Curtis on the set of 20th Century Studios’ AVATAR: THE WAY OF WATER. Photo by Mark Fellman. © 2022 20th Century Studios. All Rights Reserved.

And one of the main challenges of the water was interfacing above and below the surfaces. So Baneham collaborated with Cameron on a solution. “The little polymer balls that we have floating on the surface served a dual purpose for us,” he said. “It removed reflection and reflective refraction and underneath reflection above so that you don’t get light bouncing back into the cameras on either side, and you don’t get bleed or contamination from one than the other. And then, it allows your subject or your actor to sit in the medium in between the two. We’ll call the interface and just reassemble the body in real time. So it’s perfectly safe.”

“When you’re doing these water effects, you need now the motion, you know, the physical simulations. And that was, you know, taking clues from what the water was doing in the tank,” said VFX supervisor Joe Letteri. “But also adjusting for what was captured, especially camera framing. When you’re doing shots on or in the water, your camera tends to be moving with the water. And that changes your shot composition. When you do a simulation, simulation by its very nature is okay. You start a process and hope you get something that you like at the end. And in this case, that also had to serve the purpose of it couldn’t affect the shot composition.”

So when it came to realizing those emotional performances, it required new ways to capture them in ways that you can feel like you are a part of the story. “Tsireya, when she’s diving down, and she rolls over on her back to tell the other kids to come down again, that’s just pure performance,” Letteri said. “And that’s performance in water; you would not get that any other way.”

“These characters are more aquatic. They’ve got those big, broad tails for swimming that get worked into the animation. In addition to what the actors could do to help with that fluidity, that sense that they’re at home in the water,” Letteri added about the performance capture technology.

Avatar: The Way of Water is out in theaters now.