Kate Winslet broke Tom Cruise's underwater filming record from Mission: Impossible - Rogue Nation (2015) of six minutes with a record of seven minutes and 15 seconds.
According to James Cameron, the Avatar sequels were such a massive undertaking that he divided the four scripts between the writing team of Rick Jaffa, Amanda Silver, Josh Friedman, and Shane Salerno. Cameron delves further explaining the story process: "I think we met for seven months and we whiteboarded out every scene in every film together, and I didn't assign each writer which film they were going to work on until the last day. I knew if I assigned them their scripts ahead of time, they'd tune out every time we were talking about the other movie."
Sigourney Weaver trained in breath-holding to shoot the film's aquatic motion-capture sequences. She also joined her younger co-stars in learning underwater sign language and parkour, for scenes of Na'vi teens running along tree boughs or racing to the tops of floating mountains. "I was determined to be able to do everything they did. I didn't want anyone to say, 'She's kind of an old lady,'" Weaver says. "We all had to be really fit, and parkour is a very good way of getting there." Other cast members participated in knife-fighting and archery lessons, but "Kiri is not a fighter," Weaver adds. "She's a very gentle person. She can be filled with rage, and she's very sensitive to injustice and cruelty, but she doesn't use weapons. She has other powers."
In 2013, Cameron, armed with thousands of pages of notes expanding the world of Pandora, decided on the aquatic setting and set a team of writers to pen the sequels. But Jon Landau, who has produced all of Cameron's films since Titanic (1997), immediately foresaw a problem: The technological processes used to capture actors playing Na'vi on dry sets did not yet exist for capturing them wet. "Right away we started doing R&D," he said, "because no one had ever done performance capture underwater." all of which the cast and stunt teams performed, outfitted with special wet suits and facial capture camera rigs, while free diving in the water.
James Cameron: voice on the ship when Quaritch first wakes up. ''Stand by. Two minutes to Pandora insertion. Secure for Delta V.''