for the original “Avatar” Writer-director James Cameron made extensive use of cutting-edge performance capture technology. That allowed his human cast to portray ten-foot-tall, pointy-eared, blue-skinned aliens called Na’vi, inhabitants of a jungle moon called Pandora.
These are milestones in a filmmaking career, from the shimmering water tentacles of “Abyss” to the shape-shifting liquid metal assassins of “Terminator 2: Judgment Day” to the largely computer-generated ships. It was a visual effect. In “Titanic”, computer-generated passengers live.
With the long-awaited ‘Avatar’ sequel, Cameron sets out to explore Pandora further. The script he wrote with Rick Jaffa and Amanda Silver depicted many scenes in and out of water with a semi-aquatic Na’vi clan called Metkaina.
There is no usual Hollywood “dry for wet” performance capture technique when it comes to achieving these watery scenes. The actor hangs from a wire, feigns weightlessness, and performs a vague swimming motion in the air. According to Cameron’s crew, the director insisted on “wet for wet.”
Richie Baneham, visual effects supervisor at Cameron’s production company, Lightstorm Entertainment, said, “It comes down to the credibility of an actor’s performance.” It informs the choice of actors, that’s what we’re after, and that’s why it feels real.”
Released Friday, Avatar: The Way of Water is underwater performance capture, another milestone in the evolution of visual effects technology.
The first experiment took place in Avatar producer John Landau’s backyard swimming pool. The performance his capture tank was built at Lightstorm his entertainment facility in Manhattan Beach, California. The tank was 32 feet deep and had a capacity of approximately 90,000 gallons. (By contrast, the seawater tank he built for “Titanic” held 17 million gallons.) In addition to the observation deck on the deck, there are windows in the walls of the pool for photographers to shoot. Yes, giving the place a laboratory look and feel. aquarium.
At Cameron’s request, the tank also simulated waves and currents. “Oh my god,” Baneham remembers telling his colleague.
One of the main issues the crew faced was keeping overhead studio lights from interfering with the performance capture data. For this, Cameron suggested spreading a layer of small polymer balls across the waterline. This diffuses the light inside the tank while allowing the actor to safely surface. He used basic techniques to simulate the depths of a dark ocean in “The Abyss.”
Something else that would have inconveniently disrupted performance capture: actors with awkward breathing needs. The cast members gasped, not only during the take, but the moments leading up to it. Not only did they get their scuba certifications, but they also received training from freediving instructor Kirk Clack. Kate Winslet proudly holds his freediving record with a cast of 7 minutes and 14 seconds.
For occasional propulsion in the water, performers wore jetpack-like devices. There was a safety diver on hand and a hot tub for the actors between takes.The main cast shares scenes with professional underwater dancers and gymnasts.
A large amount of performance capture data was collected this way. As a next step in the process, that data was shared with Weta FX artists. Weta FX is a visual effects company co-founded by Peter Jackson in Wellington, New Zealand.
Weta artists transformed wetsuit-clad performers into Na’vi. They also created highly detailed digital environments, shifting the action from chlorinated tanks to enchanting underwater realms rich in flora and fauna. According to Weta, he created 57 new species of marine life for the film. Weta artists also consulted researchers at Victoria University of Wellington on coral reef biology. “There are no free trips to the Bahamas,” joked Weta’s supervisor, Joe Letteri.
Avatar: Path of Water is the company’s largest visual effects project to date. He’s the only two shots in the entire film that don’t include visual effects.
Despite the lengthy skin-pruning sessions in the tank and the vast amount of water in the sequel, nearly all the water in the film is computer-generated. Water was involved.
To bring Pandora to life, Weta’s team had to become experts in photorealistic representations of complex physics, not just fluid dynamics. Splash, splash, splash, splash – in industry parlance – had to be “solved.”
Eric Saindon, another effects supervisor at Weta, said: “Proper wave flow in the ocean, waves interacting with the character, waves interacting with the environment, thin films of water running on the skin, hair movement when wet, light refraction in water. Everything is physics. I wanted it to be accurate.”
As part of their research, the team captured hundreds of hours of reference footage. The way the wind ripples on the surface of the water, the waves crashing against the rocks, the movement of seaweed, and so on. Saindon asked his friend to submerge himself in the water with his camera so the team could study the effects of water on curly hair. “Our pool wasn’t the warmest in the world. I don’t think she would do it again for us,” he said. Did.
Weta is a pioneer in how to make things look wet, and recently filed a patent for “Method for generating visual representations of collisions between objects and fluids”.
This innovation was particularly useful in one sequence in which a human character named Spider was spawned by Na’vi’s group on top of some rocks, dripping with water. The shot blends live-action footage of actor Jack Champion shot in a wave pool with CG Na’vi of him.
As Saindon pointed out, Na’vi’s simulated water had to look as convincing as the human characters’ real water. And we don’t want you to think about it. ”
It also requires a lot of horsepower. That scene alone took him two weeks for Weta’s system to simulate just the movement of the water. This predates the millions of processor hours required to render graphics. (The total amount of data stored in this movie was 18.5 petabytes for him, but for “Avatar” he needed 1 petabyte.)
Another sequence has a boat crashing through a fully simulated wave. “People would think we were out on the open sea,” said Sainn.
The results are spectacular in a way, but the point of this kind of painstaking work isn’t to draw attention to itself. It’s just the effects that make the movie work,” he said. “We just want people to watch the movie and forget that we did something.”