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2.5 VRML (Virtual Reality Modeling Language)

VRML, first known as Virtual Reality Mark-up Language, was conceived in the spring of 1994 at the first World Wide Web conference in Geneva as a three-dimensional web standard to parallel HTML. A mailing list, started by Wired magazine, soon became the on-line forum in which the first specification of VRML was developed. The name was swiftly changed to Virtual Reality Modeling Language to emphasise that the language was primarily concerned with three dimensions, not just text.

VRML 1.0 was based on the Inventor file format from Silicon Graphics, and could be used on a wide variety of platforms. Several browsers were created, but interaction and animation were not included in the specification, and work soon began on VRML 1.1, swiftly followed by VRML 2.0. Eventually a working group asked for proposals from individuals and industry to develop the software and language needed and these proposals were debated on the VRML mailing list. Silicon Graphics Incorporated won the battle that commenced (Microsoft's ActiveVRML failed to impress, although it has since been further developed and is part of Microsoft's ActiveX toolkit). Throughout the development of the language, interaction through the mailing list provided suggestions and comments from the on-line community, and, as such, VRML 2.0 evolved from a collaborative effort of individuals and industry. In June 1996, VRML 2.0 was submitted to the International Standards Organisation, and adopted as the web standard for three-dimensional environments (Marrin and Campbell 1997).

A VRML document, identifiable from the suffix '.wrl', is an ASCII text file describing a three-dimensional scene. This text file contains a list of commands that instruct the computer to place objects of given forms in certain places within the 'world'. Basic objects can be constructed from primitives, such as box, sphere, and cone, which are simple, pre-defined, geometrical shapes. The use of primitives generates small, quickly rendered, files. It can take thousands of polygons to create a single building or landscape. Basic animation, lighting, and interactivity are supported, and the world can be linked using hypertext to other Internet worlds and pages. The files can either be scripted by hand, or written with the help of a 'world-builder', a WYSIWYG (What You See Is What You Get) application that facilitates the creation, placement and sizing of objects within the scene. Various conversion packages also exist which can generate VRML files from standard three-dimensional drawing applications.

The resulting file can be parsed by a browser into an intelligible, interactive form. All browsing is done on the client machine, resulting in low bandwidth requirements and hardware independent distribution.


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