Over the last three decades, James Cameron has been obsessed with water, chiefly filming in it. And with the imminent release of Avatar 2: The Way of Water, the Titanic director takes motion capture to a new level, by developing an underwater mocap system, and a 3D-based beam splitter camera rig for creating the iconic CGI Na'vi characters.
Check out this video from Frame Voyager for more.
The Journey Begins
Cameron’s underwater journey began with the 1989 sci-fi drama The Abyss. The director filled an abandoned nuclear plant with millions of gallons of water and used it as the primary set for filming several pivotal underwater scenes. The pool simulated the deep-sea ocean floor, and the entire cast and crew had to become scuba certified to be able to film the movie safely.
The film was forced to begin production even before the construction of the deep water research station set was finished, and the production had to place black beads onto the surface of the underwater tank to break up the surface reflectivity that would cause the filming to be reflected toward the camera.
The six-month, 70-hour-per-week schedule was punishing, and Cameron nearly drowned when his scuba tank ran out of air and he was forced to skyrocket up to the surface because a safety diver wouldn’t reach him in time. Perhaps inspired by this experience, actor Ed Harris accused Cameron of keeping the safety divers just out of reach to give him a realistic sense of terror while swimming across the bottom of the ocean. The actor stated after the experience that he would never work with Cameron again.
But the lessons Cameron learned on The Abyss would continue to serve him well as he moved to film other underwater scenes, including from films such as the original Avatar, Alita: Battle Angel, Sanctum, andnow Avatar: The Way of Water.
And in between, as explorer-in-residence with National Geographic, Cameron made several real-life journeys down to the wreck of the Titanic and the Marianas Trench in the Pacific, developing deep-sea filming lights and cameras for several documentaries.
But for Avatar: The Way of Water, Cameron simply wasn’t happy with how wire work was used to simulate the underwater activity of the Na'vi in the seas of Pandora. The actors and stunt doubles pretending to swim seemed to be more jarring and fake.
So Cameron filled a 900,000-gallon swimming pool and had free drivers train the cast on how to hold their breath for up to nearly eight minutes. The actors were even equipped with underwater jet packs to make their swimming capabilities look more fluid and alien.
Shooting Underwater in 3D
As for the camera technology, Cameron’s crew worked with Sony to invent a motion capture system based on the modular Sony VENICE 2 cinema camera.
“They listen to the filmmaker about what features they want in a camera, and they’ll go way out on a limb,” said Cameron of his career-long collaboration with Sony. “I know that they’re going to deliver the engineering. If they say they can do it, they will do it.”
The system was able to capture the actors' performance underwater by working in concert with motion control cameras, a portion of which was mounted above the surface, while other waterproof motion cameras were mounted underwater.
There were also close-up cameras that were redesigned to be waterproof, to capture the facial reaction data of the actors.
The main camera is based on a pair of Sony VENICE cameras that were reconfigured by Pawel Achtel, ACS, and utilized with a deep 3D underwater beam splitter and Nikkor Nikonos Underwater lenses designed to capture underwater without optical distortion. Cameron opted to use 3D technology simply because we all have two eyes and displaying the video in stereo gives the audience a realistic and immersive sense of actually being there.
Credit: Pawel Achtel ACS
“DeepX 3D is the world’s first, patented camera system designed for uncompromised capture of stereoscopic 3D images underwater when using submersible lenses," Pawel said in a 2015 statement. "Unlike other underwater 3D beamsplitter systems that house a beamsplitter behind a flat port, DeepX 3D is completely submerged in water. Such revolutionary design allows a wide angle of view, no geometric distortions, and no chromatic aberrations that are associated with traditional designs. It provides virtually unlimited sharpness from corner to corner. DeepX 3D is the only underwater 3D system allowing immersive, high-resolution stereoscopic 3D images underwater. It delivers more than an order of a magnitude more detail than it is possible with traditional housed systems”.
Credit: Pawel Achtel ACS
The challenge, though, was that using two cameras required the challenge of syncing the camera lenses and focusing them simultaneously.
Cameron’s Fusion camera design benefited from a pair of smaller VENICE cameras with a separate optical block and the brain attached to a shoulder mount. With a beam splitter to simultaneously film two images at a time and align them, the rig was very light at under 30 pounds.
However, even then, they ran into a problem with bubbles forming on the lenses while shooting underwater. To combat that, the cinematographers used Kodak Photo-Flo, a chemical gel that could be spread onto the lens to break up the tension and prevent bubbles from forming.
Cameron even brought back the surface beads, this time made of white ping pong-like balls, to cover the surface to break up the reflectivity again.
But how did that work with the motion capture systems? Turns out the system used was an optical system that tracked the infrared spectrum, which could be picked up by the cameras because of the opaque nature of the system.
With these tools, Cameron was able to shoot the film in 3D at 8K with incredible detail and resolution. From there, it was up to Weta Digital to create complicated hair physics to create the movement of hair moving around underwater and CGI skin wicking away water as they emerged on the surface.
For shooting pure CGI shots, Cameron used a virtual camera rig to take the motion capture data and overlaid it with a virtual capture environment, tracking the real camera in virtual space.
FilmRiot’s Ryan Connolly shows roughly how this could be done in the video below:
Was it worth it to shoot in 3D, a technique that has always been considered more gimmick than a viable filming technique? Well, Cameron is teaming up with Christie Laser Projectors to develop a 3D laser projector that would project a 3D image without the need for special glasses to enjoy it.
The projector won’t be ready before Avatar: The Way of Water hits theaters on Dec. 16, but if Cameron can pull that off, there are three more sequels on the way. All that remains is if the sequel itself can live up to the hype and expectations of following the record-breaking original 13 years after it became the highest-grossing film of all time.
If it can, then imagine what Cameron will do for the upcoming films. We can't wait.
Source: Frame Voyager