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Getting Started with VRML

by Dennis McKenzie

By now, everyone who has access to the Internet has come across some mention of Virtual Reality Modeling Language or VRML. In fact, since the 3.0 beta version of Netscape comes pre-configured with the Live3D VRML plugin, many websurfers have viewed a VRML "world". The initial reactions range from "big deal" to "WOW!!". To many, the real time graphical representations of a three-dimensional space are little more than crude imitations of the spectacular two dimensional computer-generated graphics that we see everywhere in the visual media. Others find that the experience of exploring a VRML world borders on the religious!

Still in its infancy, VRML is just now becoming capable of allowing the objects that comprise its worlds to exhibit rudimentary behaviors. Version 1.0 allowed only the display of static worlds in which objects were incapable of movement or interaction with the user. Recent extensions to version 1.0, such as the Spin node in Netscape's Live3D, allow for some basic movement. Other browsers, like Black Sun's CyberGate allow for multiple participants, represented by a virtual beings called "avatars" to not only be in a world at the same time but also communicate with other people visiting that world.

VR and VRML: A Distinction Becoming Fuzzier

VRML, barely a year old, is the younger sibling of the much hyped Virtual Reality and is intended to make virtual worlds available over a shared computer network, such as the Internet Although VRML is really just a computer language that describes three-dimensional objects, it has come to signify Virtual Reality's arrival on the Internet. The line between VR and VRML is becoming gradually fuzzier. Recent additions to the VRML spec will allow users to interact with objects in the world. Interaction has always been the key ingredient of a "virtual" world.

VRML World Building: A short history

In the beginning, all VRML code needed to be written by hand but very few people were interested in such an undertaking. Initial worlds were composed mainly of the simple geometric shapes that formed the core of the language. Thus, the VRML fare was comprised largely of Spheremen and Cubeworlds.

Shortly after the first VRML browsers were made public, translators for three-dimensional CAD programs were written, allowing VRML code to be generated fr omobjects built in such popular programs as 3D Studio. Soon after followed programs called builders which were written specifically to generate VRML 1.0 worlds.

Such programs have steadily become more functional and as easier to use. Today, A VRML novice with no understanding of the language can build a complex world through a simple, intuitive point and click interface in a short amount of time. At present, however, there are no builders available that meet the VRML 1.0 or VRML 2.0 specification for providing object behaviors. To add action to a VRML world, the creator must be able to edit a VRML file by hand.

Building a World

The VRML world is composed of objects, which are in turn composed of polygons. A polygon is a flat, multisided surface such as a triangle or square. The more polygons that are used to represent an object, the more detailed and realistic it is likely to be.

However, increasing the amount of polygons in a file will not only slow down the rendering speed, causing jerkiness of movement, but also increase the size of the file, slowing transfer speed. The simplest virtual world would be comprised of a camera (user viewpoint), a light, and a single point. Such a world would render quickly and be very small, but wouldn't be of much interest to anyone!.

Texture Adds Realism

The VRML author can add realism to a virtual world through the use of texture mapping. Textures are two-dimensional images painted on the face of polygons and can create the illusion of great detail. (See the article on texture mapping by Cindy Reedy in this issue). They also slow down rendering speed, and must be transferred as separate files.

A world that is bogged down with an extreme amount of polygons and/or textures can be difficult to navigate and, for some slower machines with little memory, impossible to render. Thus, the VRML author must often walk the a line between detail and speed. Since the new VRML spec allows for behaviors, it behooves the VRML creator even more than before to keep both polygon numbers and texture file sizes down to allow more of the processing power of the computer to be devoted to the computation these behaviors.

Once the fledgling author has mastered the techniques of modeling objects and placing them in the virtual worlds, his/her imagination becomes the only limiting factor in what s/he can create. The world-builder is god to the inhabitants of the virtual world; where they live, how they look, and, with the additions of behaviors, how they interact with their environment are all decisions made by the world's creator.

Some World-building Tools

Here are some great builders for a new world-builder to get their feet wet:

The virtual universe is waiting to be filled with new and exciting worlds of the imagination. Happy building!

Relative URLs

Dennis McKenzie is a part-time VRML and VR programmer, and maintains the popular Proteinman's Top Ten for Aereal Inc. He started and headed the award winning Community World Building Project, and has won several individual awards for his virtual worlds.

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