If incorrectly dealt with, the eyes of the character would appear to be printed on the glasses, not behind the glasses. While the glasses have a depth from the camera, the eyes behind them are further away. One of the trickiest problems can be, say, glasses on a live-action character. In mono, although this shot may be extremely creatively valid, it is only when the shot is converted does it seem empty or oddly distributed. For example, most staging of a stereo scene would have a distribution of the objects over the immediate foreground, avoiding the clumping that may seem odd when all the props are at the back of a room. A mono film may be poorly composed from a stereo point of view. Most stereo films are shot with an understanding and consideration of the stereo nature of the experience. The technique works well for building, hallways and other regular and mostly rigid body solutions but most films are about people – normally with soft edges such as hair, etc. While some shots respond well to re-projecting or ‘camera mapping’, the mono footage over 3D models and then filming the stereo by rendering the 3D scene from two virtual cameras, this rarely works well for people in movement as the difficulty of generating accurate 3D models to map onto renders the approach extremely expensive. A character could easily have 7 rotos in addition to their outline for features such as nose, eyes, etc and all of these must be conceptually and logically correctly placed based on z depth. Not only is a roto required for the outline of any character in shot, if they are closer than say a wide shot, internal mattes are also required to generate different depths for different parts of their bodies. Cardboard cutouts and the need for roto.While amazing work has been done with programs such as Ocula by the Foundry, and Mistika by SGO (see below), the process is far from automated. A depth map is needed of the scene to determine the correct distribution of the objects for the second eye.That means a second eye will see around things the original eye won’t and thus there is missing background information to be replaced. The problems with generating a second view or second ‘eye’ for stereo conversion are: Yet another significant company is Cinesite in London who not only delivered stunning visuals for John Carter but also had to deal with converting the film from anamorphic 35mm to digital stereo. Stereo D, another leading company, converted Titanic, while Legend3D worked on Transformers: Dark of the Moon. There are several leading companies in this area today such as Prime Focus, who after a battering of critical opinion on the conversion of Clash of the Titans, recently converted Star Wars Episode 1 and the new Wrath of the Titans. For example, the opening macro eyeball shot was far too close for a stereo camera rig to film, and this first shot of the film was converted stereo from 2D. Even Avatar required tiny amounts of stereo conversion. For everything else live-action, normal stereo production is hard. Image from Tangled.ģD animated films, such as Toy Story 3, Up, Brave, Tangled and others find it easy to correctly generate stereo imagery from either stereo renders such as RenderMan or just rendering the entire scene from two similar but offset virtual cameras. Below his comments are included as part of our special case studies on major feature films. John Knoll (ILM) oversaw the stereo conversion of the Star Wars films for director George Lucas starting with Star Wars – Episode One: The Phantom Menace and you can watch our detailed chat with John on that process here. Stereo conversion is also needed for converting older films – such as Top Gun or the Star Wars franchise. Thus, even on films shot in stereo, there may well be a need to convert some footage and that high-quality conversion is an important tool in the box of any effects house. Even on a stereo film, lenses and situations oftentimes render a single camera the only viable solution. Yet many filmmakers do not want the physical size of an onset stereo rig, or they prefer to shoot film (ruling out stereo in-camera, effectively) or want to use anamorphic lenses which are extremely difficult for stereo native capture. Many people argue that if you want a film in stereo you should shoot it in stereo.
#W1070 2d to 3d conversion update plus
We originally published an Art of Stereo conversion two years ago, and this is a new updated version of that story covering The Avengers, Titanic, John Carter, Star Wars: Episode I, plus the newest techniques and approaches. Stereo conversion, or dimensionalization as it is sometimes called, is the process of making stereo images from non-stereo traditional 2D images.
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