James Cameron Talks About Using Underwater Motion Capture for the AVATAR Sequels

One of the very first things we learned about The Avatar Sequels was that writer/director James Cameron would be taking the characters underwater on Pandora. Cameron has been hyping that the follow-up films will offer brand new visuals and a good chunk of these will happen underwater. But shooting motion capture underwater is something that has pretty much never been done before. It turns out that developing this process is part of the reason it has taken so long for The Avatar Sequels to happen.

Recently Cameron sat down with Collider and talked about the process of shooting underwater motion-capture for Avatar 2 and 3 which is currently in production and as Cameron explains, it sounds incredibly 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.”

Even though it has been tough, Cameron said he is happy with the how things have turned out so far:

“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.”

Cameron also explained that most of the underwater stuff in The Avatar Sequels will happen in the second and third installments, but the final two movies will only have some:

“Now, we’re still working in our small test tank. We graduate to our big tank in January. There’s a tremendous amount of water work across Avatar 2and 3. It’s ongoing into 4and 5, but the emphasis is on 2 and 3.”

Cameron is shooting a lot of these movies at the same time, for example Avatar 2 and 3 are filming simultaneously, then Cameron will take a break to finish post-production on those two sequels only to go back in and shoot Avatar 4 and 5 at the same time to wrap things up. 

Avatar 2 is set to hit theaters on December 18, 2020.