Three-Dimensional Display

In the 1930s, radiologists tried to create three-dimensional images by hold­ing up two slightly offset X-rays of the same object and crossing their eyes. Now the same effects can be achieved by computers. With 3-D technology, flat, cartoon-like images give way to rounded objects with shadows and tex­tures. Artists can even add "radiosity," so that a dog standing next to a red car, for instance, will pick up a red glow.

During the past several years, many people have come to experience 3-D images not only through random-dot stereograms like the Magic Eye Three-Dimensional Display books but also through videogames using virtual-reality head-mounted displays. Now companies are moving beyond VR goggles to design 3-D displays that produce two different eye views without glasses. In one design, for instance, the display remotely senses the viewer's head movements and moves lenses to change the scene presented to each eye.

In early 1994 the Japanese manufacturer Sanyo demonstrated two types of 3-D systems on television screens. One was an experimental 3-D HDTV sys­tem that projected a 120-inch picture on a theater-type screen and required the use of special glasses with polarized lenses. The other, which Three-Dimensional Display involved neither HDTV nor special glasses, used what appeared to be a normal 40-inch TV set, with a screen that employed hundreds of tiny prisms/lenses. "The 3-D effect was stunning," wrote one reporter who saw it. "In one scene, water was sprayed from a hose directly at the camera. When watching the replay, I had to control the urge to jump aside."

Virtual Worlds: 3-D in Cyberspace

Virtual reality, as we explained, involves head-mounted displays and data gloves. By contrast, a virtual world requires only a microcomputer, mouse, and special software to display and navigate three-dimensional Three-Dimensional Display scenes. The 3-D scenes are presented via interlinked, or networked, computers on the World Wide Web part of the Internet. For example, users can meet in three-dimensional fantasy landscapes (using on-screen stand-ins for themselves called avatars] and move around while "talking" through the keyboard with others.

Virtual worlds are a feat mostly of software rather than output hardware, although the subject deserves discussion here because of the possible trans­formations for output this kind of three-dimensionality promises. Internet sites are rendered in 3-D thanks to software known as VRML, for virtual real­ity markup language Three-Dimensional Display (discussed in Chapter 11). To view a site in 3-D, you need to download a piece of software called a VRML browser, such as WebFX or WebSpacc. This enables you to get into 3-D environments such as "Habi­tat/' "AlphaWorld," and "WorldsAway." In WorldsAway, for example, instead of having a text-based "chat room" or discussion group, you appear "live" as your cartoon character avatar in the three-dimensional space. "When you talk, a little balloon appears over your head on the computer screen, containing your words," explains one report. "When you wave, your image waves. . . . Maybe you will go Three-Dimensional Display for a walk in the community's virtual woods, with whomever you've befriended online."


The advances in digitization and refinements in output devices are produc­ing more and more materials in polymedia form. That is, someone's intel­lectual or creative work, whether words, pictures, or animation, may appear in more than one form or medium. For instance, you could be reading this chapter printed in a traditional bound book. Or you might be reading it in a "course pack," printed on paper through some sort of electronic delivery sys­tem. Or it might appear on a computer display Three-Dimensional Display screen. Or it could be in mul­timedia form, adding sounds, pictures, and video to text. Thus, information technology changes the nature of how ideas are communicated.

If materials can be input and output in new ways, where will they be stored? That is the subject of the next chapter.

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