by Mike Hendry
Senior Technical Writer
Interdigital Communications
Originally published in News & Views November, 1997 issue.
Copyright 1997 STC-Philadelphia Metro Chapter. For permission to reprint
this article, contact the Managing Editor.
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Now that you’ve become familiar with browsing Virtual Reality Modeling Language (VRML) worlds, it’s time to create some of your own. All of the companies that sell VRML World Builders offer free trial downloads. I’ve tried a couple, but more are surfacing every day, so check out the VRML Repository for complete listings and links.
I’ve tried three World Builder demos. Sony’s Community Place Conductor and Ligos’ V-Realm Builder both had unintuitive interfaces and inadequate help files. (Note: this may change with later versions.) ParaGraph Corp.
(www.paragraph.com) offers a very generous trial version of Internet 3D Space Builder (ISB), with a good interface and extensive help. I haven’t had a chance to try Virtus 3-D Website Builder (www.virtus.com), but I’ve heard good things about it. I’ll use ParaGraph’s ISB as an example for this article.
Creating a World
The easiest way to build a world is to use the set of predefined shapes. These come in several flavors: cube, cone, pyramid, sphere, etc. Add shapes together to create complex objects. Apply colors or textures, using external texture files, and position your objects in the world. Then set up cameras where to guide your audience through your world, bringing them to the information they need. If you purchase the software, you’ll get large libraries of pre-built objects, textures, pictures, movies, and sample scenes. The drawbacks to ISB are that it doesn’t support lighting, animation, or some of the other, more complex features of VRML.
Problems with World Builders
World Builders are like the HTML editors of a couple of years ago. They can generate the code, but are not very efficient. VRML has predefined shapes that browsers can render quickly, but, as far as I know, the World Builders don’t use them. For every shape they use the IndexedFaceSet, which describes the shape point by point. This results in large files.
If you are just experimenting, or creating simple worlds, the World Builders will probably do what you need. But if you are doing serious work with VRML, you will still need a working knowledge of the language. Just like the old HTML editors, to get VRML to do what you want most efficiently, you’ll need to go in and tweak the code.
Making Efficient Worlds
Describing 3D worlds can result in large text files, and truly high speed Internet access is not available to most people. Some ways to make your world more accessible are:
- Compress your files. Most VRML browsers support gzip, a type of file compression. There is a version available for DOS (I don’t know about Macintosh), and newer World Builders are starting to support gzip compression
- Minimize your use of textures. Color your objects instead of mapping a texture wherever possible. Each texture file must download separately. Also, use the minimum resolution in your texture that you can.
- Try to replace the IndexedFaceSets of common shapes with the VRML predefined shapes, where possible (This can be tricky, you’ll have to know VRML pretty well).
The best way to get started is to jump in and start modeling. ISB will make it
fairly easy to make some worlds, then open them up and study the VRML code.
If you plan to tweak the code, you will definitely need a good book on the
subject, or visit some of the online tutorials available. Be sure to visit
my Web site, at http://ourworld.compuserve.com/homepages/mhendry, for more
information and links to sites discussed here.
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