The Essence of Html

Ever since the publication of Vernor Vinge's ground-breaking science fiction novelette True Names in 1978, many computer programmers and users have been fascinated by the ideas of "virtual reality" and "cyberspace"--computer interfaces using 3D surround graphics with which a user could interact in something like the way our physical bodies interact with the real world.

In 1994, two Silicon Valley programmers with backgrounds in computer graphics went public with the provocative idea that the distributed-hypertext model of HTML might be used as a foundation for building cyberspace. A working group began adapting and enhancing a graphics-description language previously developed at Silicon Graphics Inc. to be used with HTML and Web software.

The result was Virtual Reality Markup Language (VRML). VRML follows the HTML model in several important respects. Like HTML, VRML is a content-based, plain-ASCII markup language that describes its universe at a high level, and leaves it up to the browser or client program to make detailed presentation decisions. VRML technology has since evolved even more rapidly than the Web itself. As of April 1997, Microsoft was in the process of extending the VRML standard, and support for an earlier version of VRML was available as an add-on for the popular Netscape browser for PCs.

VRML documents describe worlds populated with 3D shapes. Developers build objects from basic shapes, such as cubes, cones, and spheres, with a variety of surface effects, including texture maps and lighting, available for composing realistic objects. It's possible to associate URLs with objects in a VRML world in such a way that when a user touches the object, they are transported to another VRML world, an HTML document, or a CGI (Common Gateway Interface) script (which itself may generate a VRML world).

Some intriguing demonstration interfaces to large databases have already been built and suggest the beginnings of true cyberspace architecture. So far, however, these demonstrations fall short of the strong virtual-reality experience depicted in science-fiction books and movies. Three related problems bar the way. The design problem is that VRML currently has no capacity to do animation. VRML worlds are static. While it's easy to move the user's viewpoint in a VRML world, the only way to actually move or alter a VRML object is to generate an