We've known for a long time that the sequel to Avatar was supposed to deal with the oceans on the planet Pandora. However, it turns out that not only will the film take place near the water, but actually in it as well. Rather than simulating scenes that are supposed to take place in the water, Director James Cameron says that he's actually shooting motion capture scenes underwater with his actors. According to Cameron...
We've already been doing underwater capture. We did a scene last week with six teenagers, well, actually five teenagers and one 7-year-old underwater holding their breath for a couple minutes and acting, actually doing a dialogue scene under water because they speak kind of a sign language.
While it's been years since we first learned details of the forthcoming Avatar sequels, one of the things that has remained constant is the idea that the next movie would focus on the reef people of Pandora, the tribes of Na'vi that live around the planet's oceans. We knew that at least some of the movie would take place underwater, but that doesn't make this any less of a surprise. Considering how everything in Avatar was being handled using motion capture and CGI, one was certainly led to believe that the same would be done using any underwater scenes in Avatar 2. However, James Cameron tells Vanity Fair, that, in fact, the underwater sequences are apparently being handled practically, with the actors going underwater and actually performing while submerged, including dialogue scenes.
As one might expect, there are a series of complications that arise when one wants to film movie scenes underwater. The primary one dealing with one's ability to breathe. James Cameron says that Kate Winslet had to be taught to free dive as the actress insisted on doing all of her own underwater work. Meanwhile, the rest of the cast has learned to hold their breath for several minutes at a time.
[Kate Winslet] plays a character who's part of the Sea People, the reef people. The one thing she did do is demand that she do all her own water work. I said, 'All right, that's fine, we'll have to teach you how to free dive.' The other actors are up to three- and four-minute breath holds.
Three and four minutes, while not exactly world record territory, is still a significant amount of time to hold your breath, especially while doing something else, like communicating with other people via sign language. The most difficult thing is probably looking like it's no big deal that you're underwater, even while your body is trying to get air.
Avatar 2 is being filmed concurrently with Avatar 3 and is set for a 2020 release. Once those films are completed production is set to begin on Avatar 4 and 5.