How it works: XNUMXD movies

From the XNUMXD revolution: A look inside the show-stealing technology used to create James Cameron's Avatar

An article from Popular Science

James Cameron is stubborn. Almost a decade ago, he decided to shoot his sci-fi adventure film, Man-versus-Alien - Avatar in 1000D; But he refused to start production until the technology reached a point where it could convince viewers that they could penetrate the screen and wield a bow and arrow alongside the Na'bi, the film's three-foot-tall cat-faced blue aliens. To give the scenes realistic depth, his son Cameron, who resurrected the computer-animated liquid metal T-2 in Terminator XNUMX, and camera geniuses Vince Pace and Patrick Campbell, the Pace/Cameron Fusion Camera System capable Capture the images in the same way that the human eye does. Next, Cameron used a virtual camera to walk – or fly – around the virtual world to capture all the angles of the Na'bi he wanted and combine the resulting footage with real-life footage. Here's a guide to creating the most compelling XNUMXD movie to date. – John Scott Lewinsky

How James Cameron made a truly realistic XNUMXD movie

1. Build the stage

Array of 72 to 96 cameras, depending on the size of the set, hang around the perimeter of the sound stage and are connected to the net. At a later stage, the computer replaces the studio walls, floor and ceiling with the environment and XNUMXD rounded digital structures. The grid is also marked on the floor to give reference points within this virtual world.

2. Catch movement

Actors, weapons, and props are marked with ray-reflecting dots while the camera network follows only the movement of the dots. A computer records the movement of the points, locates their location through triangulation, and combines these data points into wire skeletons that will be "worn" in an avatar with Na'bi's computerized body.

3. Photograph in XNUMXD

In the next step, Cameron photographs the living characters in XNUMXD so that they look at home alongside the Na'bi in the virtual XNUMXD world. Older XNUMXD technology used two cameras mounted side by side to create a right eye/left eye effect. Because of their volume, these cameras were placed at a great distance from each other and could only photograph what was in front of them. The combined system consists of two cameras, but by using high-definition digital image sensors, the lenses can be placed closer to each other than the distance between your pupils. The line of sight of the lenses is adjustable, so when shooting, you can change their angle closer so that they focus on closer objects, or farther to focus on figures standing in the distance, just like your eyes do. The system combines the photographs into one image that has realistic depth.

4. Climb into the film

After the computer integrates the recorded movements into the digital environment, Cameron carries on the set stage a virtual camera with an LCD screen with buttons and grips similar to a video game remote. As it moves, radio and optical detectors track the camera's position and transmit it to computers, which Rendering the virtual world As it looks from this point of view and send it to the tablet. The action allows Cameron to walk through the virtual action zone to record the scene he wants. It can even position the vantage point to capture shots that would have required a drone or helicopter camera. Later, the XNUMXD shots of the humans can be added to these scenes.

5. Watch it

In true 144D performances, the projector alternately displays the right eye and left eye images, each in reverse polarized circular orientation, XNUMX times per second. Polarized glasses (XNUMXD glasses) ensure that each eye sees only the image intended for it.

Popular Science interview

James Cameron

Behind the XNUMXD magic is a director who won't let even the laws of physics get in the way of heroic stories.

The science advisors are annoying:

I have just enough of a science background to get me into trouble. When I wrote I thought - what can make a mountain float? If it was made of an almost pure, superconducting material at room temperature, and it was in a strong magnetic field, it would float on its own. This fact was actually demonstrated in practice on a very small scale with very strong magnetic fields. But my scientists argued that: "You will need magnetic fields so strong that they will separate the hemoglobin from your blood cells." So I said, "Well, we're not going to show that, so we're probably going to have to deviate a little from what's possible in the physical universe to tell our story."

But sometimes the scientists are useful:

I wanted to put Pandora in the Alpha Centauri star system, but we didn't find any large planets there. One of my astrophysicists said, “Well, if the Milky Way plane of the planet were tilted 60 degrees to our line of sight, the Doppler method wouldn't work because the planet would interfere with [star] Alpha Centauri A or B which is on a different axis, and then no We could see him. You would not have been able to see him even using the method of the fluctuations of the stars." So maybe there are planets there. But there can only be stable satellite orbits up to 370 million km from Alpha Centauri A, so your planets have to be close to the center, blah blah blah. So we went through the process of creating two possible solar systems there, since it's a binary star, and fleshed it out with technical research.

The audience will love the film anyway

My goal is to tell an epic story with visual power and impress the audience like crazy, and that's my goal every time I make a film. When it comes to the science behind the camera, and what it took to create the shots - I think viewers like the idea of ​​being shown something new, but I don't think they really care how I did it. I mean, I'm happy to talk about it, but I don't think it sells a single ticket.