Three-dimensional user interfaces

For typical computer displays, three-dimensional is a misnomer�their displays are two-dimensional. Semantically, however, most graphical user interfaces use dimensions - in addition to height and width, they offer a third dimension of layering or stacking screen elements over another. This may be represented visually on screen through an illusionary transparent effect, which offers the advantage that information in background windows may still be read, if not interacted with. Or the environment may basically hide the background information, possibly making the distinction apparent by drawing a drop shadow effect over it.

Some environments use the methods of 3D graphics to project virtual dimensional user interface objects onto the screen. These are often shown in use in sci-fi films (see below for examples). As the processing power of computer graphics hardware increases, this becomes less of an hindrance to a smooth user experience.

Three-dimensional graphics are currently mostly used in computer games, art and computer-aided design (CAD). A three-dimensional computing surroundings could even be useful in other scenarios, like molecular graphics and aircraft design.

Several attempts have been made to generate a multi-user three-dimensional surroundings, including the Croquet Project and Sun's Project Looking Glass.