Filmmaker James Cameron has been teasing over the years that at least part of the “Avatar” sequels will take place underwater, allowing him to create an elaborate undersea ecosystem for the planet of Pandora.
Despite the change of environment, Cameron is still getting motion capture elements of the actors, and the director has revealed to Collider that the process of shooting underwater motion-capture is very hard:
“Well, we’re doing it. It’s never been done before and it’s very tricky because our motion capture system, like most motion capture systems, is what they call optical base, meaning that it uses markers that are photographed with hundreds of cameras.
The problem with water is not the underwater part, but the interface between the air and the water, which forms a moving mirror. That moving mirror reflects all the dots and markers, and it creates a bunch of false markers. It’s a little bit like a fighter plane dumping a bunch of chaff to confuse the radar system of a missile. It creates thousands of false targets, so we’ve had to figure out how to get around that problem, which we did.
Basically, whenever you add water to any problem, it just gets ten times harder. So, we’ve thrown a lot of horsepower, innovation, imagination and new technology at the problem, and it’s taken us about a year and a half now to work out how we’re going to do it.
We’ve done a tremendous amount of testing, and we did it successfully, for the first time, just last Tuesday [November 14th]. We actually played an entire scene underwater with our young cast. We’ve got six teenagers and one seven-year-old, and they’re all playing a scene underwater.
We’ve been training them for six months now, with how to hold their breath, and they’re all up in the two to four minute range. They’re all perfectly capable of acting underwater, very calmly while holding their breath. We’re not doing any of this on scuba. And we’re getting really good data, beautiful character motion and great facial performance capture. We’ve basically cracked the code. Now, we’re still working in our small test tank. We graduate to our big tank in January.”
Cameron also confirmed that most of the water work for the series will take place across the second and third films of the series. There will be some water elements in the fourth and fifth films, but not as extensive.
This partly explains why the second and third film will be done simultaneously before taking a break and then filming the fourth and fifth films. The first “Avatar” sequel arrives December 18th 2020.