In essence, Disney's talented animators are creating a virtual space in front of the movie viewer. Done correctly, the illusion can be totally immersive, with objects placed within the stereoscopic plane at different distances and images seeming to appear across the front of the audience, extending at least halfway from the screen and appearing to travel back several hundred feet.
Neuman explains that instead of creating a right-eye image from the 2D original, which, in turn, becomes the left-eye image, Disney Animation creates unique left- and right-eye elements. "That gives us far cleaner results," the stereoscopic supervisor considers. "Instead of displacing the right-eye image from the left by 10 pixels, for example, we can use a +5 pixel offset for the left eye and +5 for the right, which delivers higher clarity and more realistic results, with less unwanted artifacts. Also, since we might need to fill the occluded space [which remains in the background when an element is moved left or right], these smaller offsets are less noticeable."
"We make sure the convergence and focus will track each object as it moves, and maintain a realistic sense of distance."Motion tearing results when an object moves too quickly across the movie or TV screen, or within the 3D space; when the viewers' eyes can't track the resultant movement, any 3D illusion will be lost.
—Robert Neuman, Walt Disney Animation Studios.
"We make sure the convergence and focus will track each object as it moves, and maintain a realistic sense of distance," Neuman states.
A conventional movie projector running at 24 fps will produce a 40 ms delay between the two stereoscopic images; other systems operating at 60 or higher frame rates will produce shorter delays. While stationary or slowly moving objects won't be affected, for objects traveling quickly, audiences might see the left-eye image at one location and the right-eye image in another location; the 3D stereoscopic effect will be corrupted.
It's also fortunate that Disney Animation embraced digital animation technologies two decades ago. Explains Neuman, "That means that we have access to layered images that can be re-processed to create the 3D versions of The Lion King and Beauty and the Beast, but each pixel still needs to be created in the new versions. It's a long, intricate process."
Disney Animation has been using digital-image technologies, as opposed to traditional painted-cell animation, since 1991, having developed a proprietary computer-based CAPS System at its Burbank animation and postproduction HQ.