This article explains the use of platform/browser-specific features to create non-standard VRML performance. Before we go further, let me say Don't Do This!. Since I use these in some of my worlds, that can seem hypocritical, but I want you to understand the tradeoffs.

• These extensions made sense a year ago when experimentation was driving the browser implementors. It was thought that successful extensions adopted by numerous modelers would make it into the next revision of VRML. Instead, a better syntax and more flexible ways of doing the same things were adopted.
• Some modelers such as myself did use the extensions. They allowed us a smidgeon of motion, backgrounds, interframe targeting, etc. and that allowed us to build more compelling worlds.

NOTE: I will show you syntax that makes it possible to add extensions such that a browser that does not implement them can skip them. It doesn't always work.

If you want animation, rich interactivity, internal spatial sound, and all the rest, stop reading this article and move on to VRML 2.0. You'll be glad you did. Enough lecture. We are sinking deep in sin; here is a hand to pull you in. These are Live3D extensions.

Adding A Background
This extension is the most useful. It allows one to put an image in the background similar to a theatre backdrop (rear curtain with scenery painted on it). Here is an example:

DEF BackgroundImage Info{
  string "chrome5.jpg"
}

This extension uses the VRML 1.0 Info node typically used for putting copyright information and other character strings that a browser could notice or ignore optionally. This extension should not cause problems for browsers that don't implement it. There are some tricks that are worth knowing. Live3D, for example, tiles an image to the background similar to a background in an HTML web page. If you want to make it big enough to cover the screen, you must size it appropriately. When doing background scenery, either the tiling must be unobvious as is the case with the ubiquitous star background that I used in the Kate Bush Homeworld, or it must fill the screen, perhaps in conjunction with a ground object such as I used in Homeground Towers. It is hard to get a background to tile. It is equally hard to get it to wrap such that the seam does not show. In the Princess of Talos, combined the chrome image with the star background and copied some stars down into the clouds. Then I cut the left edge, inverted it, and pasted it to the right so mirrored ends would meet. Then I went into the pixel editor and evened out some of the remaining seam by smearing the colors and copying over small regions. All in all, about two days of work went into making the illusion of a space station at the edge of space. The background for HomeGround Towers was stock with Live3D. Using it was simply a matter of making the ground plane big enough to hide the trees and the lake, and setting the cameras.

Adding Sound with WWWAnchor
Sound is not a natural part of VRML 1.0. However, you can use a WWWAnchor to instruct the Netscape framework to play a soundfile. Simply replace the usual target value with a sound file type supported by the browser, (e.g. .wav). It will obligingly do so by popping its sound control up over the frame and starting the sound. This kills the drama, but it works. I use Netscape frames and HTML commands instead. Here is an example of an anchor node for sound.

WWWAnchor {
 name "ruth.wav" 
 description "Running Up That Hill 
	- The Deal With God - Kate Bush."

 DEF InnerKate Separator {
  Cube { 
   height 45
   width 35
   depth 0.001 
  }
 }
}

Inter-frame Targets
With Live3D and Netscape, you can point a WWWAnchor at a framename and the system framework will cause the file named to be loaded into ' the frame specified. This is a handy trick, actually. I use it in the Talosian Spacestation. When you click on a ship, the frame loads a description of the ship, the race that flew it, and a bit of the story of the Princess of Talos. It is one way to tell a story indirectly, or to use a 3D graphic to load a parts description in a technical manual.

Adding Spins
I hesitate to show you this one. It gets me the most hate mail second only to using frames. On the other hand, it is the best deal one gets for some motion in VRML 1.0. There are two spin nodes in Live3D:

1. SpinGroup - acts like a separator and spins the objects beneath the separator.
2. Spin - is a non-local node that uses the DEF name of an object or group of objects to spin them.

DEF KBC3 SpinGroup {
 rotation 0 1 0  -0.04
}

Spin { fields [
 SFString objectname,
 SFFloat yangle,
 SFEnum axes ]
 objectname  "World"  # DEF name of object to spin
 zangle -.01732  # angle of spin, direction, and rate
 axes LOCAL  # spin in local or global coordinates
}

Notice the type designators in the fields declaration, eg, SFString objectname. This enables a conforming VRML browser to ignore this node. It doesn't always work. I made extensive use of these nodes to create the moving objects in Kate Bush HomeWorld scene.

SpinGroup is implemented by other browsers. Spin is not. Spin was an experiment by the Live3D development group that got loose, got used, and couldn't be killed with a ship's phasers after that.

Animated Objects
This trick only works in Live3D. If you take a vertical strip of square images (e.g, 128 x 128), and use them as a texture in an object such as a cube, the strip will play on the object like a flip book animation. It is a limited trick because one cannot control the frame rate except by using multiple images. Also, the size of the file is limited by the resources available on the platform. The Kate and Cathy Worlds on my homepage are animated rotating cubes.

These are very tedious to build by hand. If you don't get each photo in the strip perfectly aligned without overlapping pixels, you get little jaggy white lines at the borders of the cube.

Test the World
Before you put the world on the Web, check that all of the hyperlinks work in a local directory. Make sure all of the textures are present. In other words, exercise the beasties and look very carefully. After you publish it, look at it on the service provider's site to make sure it all got there. Sometimes, if the service provider has not configured the server, you will select it an get text back. The correct configuration on the server requires that they add VRML as a MIME type. See vrml.sgi.com for instructions.

Publish the World
Typically, I make a publish directory and put everything I need in it before transferring it to my service provider's machine. This helps when doing final testing, and when using WSFTP or some other utility to transfer the file, emptying the source directory is sufficient to make sure it all gets to the server.

Go to all of the lists you can think of, particularly the VRML list, and tell everyone you have a new world to visit. That's it. You're a WorldBuilder. Kiss On All Cheeks.

Hints
Here are some ideas to consider as you begin to create VRML worlds. Most of this is opinion and subject to argument. So take these with a grain of salt and healthy skepticism.

Reading and Sharing Code
While it ain't kosher to steal, it is common practice to read other people's code to learn the techniques they used to get a certain effect. Many of us post code to the VRML mailing list (Have You Joined? You Should!) to show off or, really to share what we have learned. Sometimes, when we initially release a world, we don't compress it for a while so it is easier for others to read the code. This act of sharing is fundamentally what has driven VRML from it's inception, was openly practiced by it's creators, and is still encouraged. As Mark Pesce, OberLord of VRML said, "A resource shared is a resource squared." It's true.

When someone posts that they have a new world or tutorial for the community, go get it and study it. When you have made something you think is cool, post to the list and share it. The other modelers out there are the best resource there is. We have been helping each other since the beginning of VRML, and that has put VRML into the mainstream of the WWW quicker than any other notation.

Acquire Techniques
There are lots of techniques for creating worlds. For example, a Russian Doll is composed of several smaller dolls, each inside another. The technique of creating objects inside objects and using cameras to guide the user into them, or letting them discover them while exploring is an old technique and cool. I learned it from Rob Geiger who used it in his BYTET world and I applied to the Kate Worlds main scene.

Everyone uses camera tours. This is setting up cameras in an order so that the NEXT key sequence animates naturally through the scene. Most of my 1.0 worlds apply this technique. Since I build slowLoaders for low frame-per-second rendering, I consider this polite.

Backlighting a semi-transparent object is another technique I acquired from theatre where we backlit scrims made of muslin to get firewall effects. I use this in the Princess of Talos to create a red glow behind the dome. In 2.0, I plan to experiment with surface animation and lighting to see if the rippling effect of striking the muslin can be reproduced.

Another very useful technique is abstraction. This is looking at real world objects and abstracting them into primitive shapes, then using those shapes in a virtual object. A lot of times, when virtualized, the shape becomes something completely different. For example, the Jeenix birds in the Isle of Jeenix are modeled on a wooden armadillo at my studio. The power spheres in the Princess of Talos are based on a parking lot sidewalk light. The landscape of the islands in the Isle are just left-overs from experiments with deforming spheres and toruses.

There is no end to this kind of synthesis and that's a joy of the virtual modeler. Joy is the reward.

"Feel It, My Love"
That title is a line from a Kate Bush song, "Feel It". I like Kate a lot. (Really?!?) Why? In the music business, she is an absolute master of making a recording that expresses emotions. This is very hard to do. I have made two albums and I can assure you, ninety percent of the effort is getting a track to "feel" right, that is, to express the emotions of the song. With it, a simple world is compelling; without it, a complex world is wasted bandwidth. EtherNoise. VRML is a craft and an art, and those that do it best create emotions in the visitor. That is the hallmark of compelling worlds.

How one achieves "feel" is very individual. The best I can say is that the world conveys a mood that comes to life as feelings as the visitor explores your world and interacts with the characters you place there and the situations you put them in. It is a difficult thing to describe, but the doing is very simple. If the world is compelling you as you make it, it will compel a visitor.

I study Kate's techniques to learn how to do this better, but the personna of the voice allows no duplicity. To get the feeling, you have to experience it. Simple technique won't do. You come off sounding like one of those noveau soul singers trilling and thrilling, but basically, walking all over the melody. Every country songwriter can get more emotion into a simple I-IV-V progression than most Juliard graduates if they have an emotion, something to say. It is inside you, and if you don't want it to come out, don't do music. If you do, prepare to work harder and take more risks. For me, VRML is the same challenge and risk, and I work hard to meet them.

I discover most techniques for creating feeling serendipitously. I do a lot of experiments with the language and suggestions made by others. Often, I stumble into some combination of objects and techniques that evoke a mood. In the Isle Of Jeenix, a VRML 2.0 world, I wondered if lights could be bound to moving objects. I put one inside an orbiting sun and discovered to my delight that the repainting emulated a shifting twilight effect. The Isle is where the Princess of Talos was exiled for a time with her pets, the Jeenix. It was a nadir of her time prior to her exile and I wanted a dark moody but temperate feeling.

Sometimes, I am trying to express a theme and achieve a function. The Russian Doll technique used in The Worlds Of Kate Bush is a thematic idea. Kate is well-known for the sexy histrionics of her early work, exemplified by the poster of her which is used for the cube at the center of the orbits. But as one goes deeper into her work, particularly through her fan club publications (exemplified by the counter-rotating cube and KT symbol inside the main cube), one finds at the heart, a mysterious evocative woman whose art and life are summed up in the words to her song, "Running Up That Hill" and quoted beneath the picture at the absolute heart of the orbiting objects.

Externally, one can click on any of the worlds and explore other aspects of her world. Internally, one sees all of this as background moving behind this marvelous artist who works reclusively protected by her family and friends. She is a mystery, but all one needs to know is there in her art if you look deep enough.

Functionally, it's a 3D table of contents; thematically, it is a vision of a woman's heart.

Learn technique, but understand the importance of "feel": you can study technique until you are a pedant. Feeling is the Master Craft; the meaning. It is the highest and the one true magic.

Using VRML Editors
In my experience, creating complex scenes is faster and more serendipitous with an editor that allows you to visualize the piece as you build it. This saves you from continuously reloading the world in a VRML browser as you create it. A good editor will make your life easier. Choose an editor that fits your needs. You will probably get more than one editor because each will have features you like or best fit your work style.

As well as visualiztion, there are some features you may need. These include:

• Dialog-driven Object Editing - This allows you to use the common dialog types of text editors (e.g, sliders, thumbwheels, entry boxes, drop down lists, etc.) to set the values of the object you are editing.
• 3D Object Editing - These are widgets created specifically for manipulating values of 3D object properties. For example, when deforming a primitive, they allow you to click on a vertex or face and manipulate it. Very handy.
• Conversion software - lets you take a variety of CAD or other graphic formats and convert them into VRML or vice versa. Very handy for getting objects from other libraries.
• DataFat Remover - Many VRML editors output complete node specificiation with useless values such as transparency 0. Since zero is the default value, this is fat in the file.
• Library Support - these are reusuable objects such as geometry, transforms, etc. that you can select from a menu and place inside world you are building. Good editors have stock objects, transforms, and textures. Study these as examples of good code. They include hardToBuild shapes such as toruses.
• Built In Gzip - To get the file size down for transmission, a compression utility called Gzip is used. A good editor could let you save in Gzip form.

What I Like
I use three editors. My personal favorite is V-Realm Builder from Integrated Data Systems. This is a VRML-centric editor. It supports all of the VRML primitives, visualization, and it has a tree display of the VRML instance as built. A tree view is valuable if you are learning VRML. It lets you see VRML syntax in one window, and transform or material effects immediately in the view windows. For me, V-Realm Builder is excellent for the object creation stage and that is the bulk of the work.

However, many objects are not efficient as compounds of primitives. They are irregularly shaped objects (e.g., most of nature) or have complex perimeters such as three dimensional text. For these, I use Pioneer from Caligari (organic shapes and three-dimensional text) and Virtual Home Space Builder from Paragraph (complex cubes that are heavily textured such as buildings).

Take Advantage of Free Demos
These companies offer good demo packages, 2.0 editors and tutorials as well as sample worlds. Experiment with these, then choose what works for you. These editors are improving rapidly and more offerings are appearing as existing and emerging companies insert VRML technology into their offerings.

Low Budget Alternatives
If you are just starting out and using an ASCII editor, most operating systems and some word processors include macro support. For example in Microsoft Windows, there is a Recorder application that records keystrokes and commands and enables you to assign these to keys in your keyboard. In the early days of SGML, we used these to store common keystroke sequences for complicated productions. The same trick works for VRML because like SGML, it's basic syntax is ASCII.

You can use these functions to record the keystrokes to build node templates, then use a single keystroke to insert the production. This is a time-saver and it helps with syntax when you forget the exact sequence. The recorder macro can also record GUI clicks and selections. This can enable you to keep a directory of named VRML objects which can be inserted directly into a file you are editing, search for common errors, replace values, etc.

If you are so inclined, word processors such as Microsoft Word have extensive macro scripting languages complete with the ability to use interactive dialog boxes. You can do very complex operations with these. If you aren't about to fork over the bucks for a real VRML editor, and you have the time and tenacity, these can be very useful tools for creating and configuring a VRML editing environment. Remember to SaveAsText and use the .wrl extension.

Silicon Graphics and Sony both offer free utilities for converting VRML 1.0 files to 2.0 files. Aside from saving you a tremendous amount of work converting language versions, both delint (bug check) the syntax of the files. They provide error messages that point to the line where an error occurs. Most VRML 1.0 browsers with some exceptions, don't provide this. It is a subject of debate whether an application built for surfing, not modeling, should. Some do, some don't. Browser writers also try to overlook common mistakes in VRML files, and while that is a help for the surfer because the browser doesn't crash and burn, it doesn't help the modeler find mistakes. That is why getting and using a delint utility is a good idea for modelers particularly as your files grow in size.

KISS Until Your Lips Bleed
A natural mistake for any modeler to make is to put too much detail into their model. One can easily get caught up in the modeling process and try to make it a perfect replica of reality. While it is good to do realistic work, in many cases, it isn't needed and in very many cases, counterproductive. Why?

• They Can't See It: Why model the inside of an object if the user isn't intended to go inside? If they are intended to, it is often better to do the inside in separate world and link to it. Some people have machines straight off the shelf with no graphics accelerators or boards that enable more than 16 colors. They can't see those subtle color variations you work so hard to achieve.
• Too Many Notes, Mozart: The audience may not stick around long enough for the complete world to load or does not have enough memory to load and render the world.
• Digging In The Dirt: A very detailed world is slow to navigate. The user scrubs with the mouse like a child digging in the dirt with a stick. It makes them mad and kills the mouse.
• This Ain't Reality: We love the term, Virtual Reality, but the fact is, this is 3D graphics and multimedia. You cannot achieve the realism of a world that will fool a human eye for long even with tools much more powerful. Don't be disappointed.
• Pet Tricks Work: Simple tricks that work and use less code leave you resources for more content.

It's fun to push the envelope. I certainly do this in my worlds, but listen carefully: I don't build worlds for a living. A lot of my VRML work is a result of testing languages, editors and browsers to see what is possible so I can make recommendations in my real job as a hypermedia consultant. What I do for a paying customer is strictly based on the requirements of that customer, not my personal whims. I'm like a jet test pilot who is paid to take risks with systems, not an airline pilot who is paid to get the passengers there safely.

Humans are quite willing to suspend disbelief for the joys of a compelling world. As you create complex scenes, and later, want to add motion and other media, economy in the initial work pays dividends.

Get an Idea and Tell A Story
Whether you are doing commercial work or art for art's sake, a world should have a reason, a theme, a point. It is easier to conceive of the objects you create and how to organize them if you have a story to tell. The human imagination feeds on structure. Ancient bards could recite thousands of lines of verse from memory and pass them on vitually unchanged for generations because they used stock characters, scenes, and strict structures.

I built The Worlds Of Kate Bush not only because I am a fan, but also because the photographs I needed could be gotten off the Internet. It saved me hours of scanning time. Those hours were diverted to learning VRML. Having a project in mind gave me a direction. The rest was mindless noodling. On the other hand, The Isle Of Jeenix was built as a private effort to make a scene for a Kate Bush recording from the Common Ground CD which she sings in Gaelic (perfect for an alien princess). It turned out to be too big for the Internet, so I used a midi file of Debussy's "Clare de Lune". The Kate version on my hard disk is much nicer, but data pipes and copyright laws being what they are, Debussy wins.

Let your characters and scenes guide you. Most of us have an inherent sense of what does and does not belong. Cultivate that sense and let it guide your work. Don't neglect serendipity: the happy accident. Keep it. It will find it's own place in your work. Like songwriting, a good idea can be found as easily in a newspaper as in a broken heart. As John Lennon and Elton John sang, "Whatever gets you through the night, it's alright."

Good Reading
The best I can do in this series of articles is introduce you to VRML 1.0. There is much more to learn. I suggest one of the following two books. Mark Pesce's book is the best introduction to VRML I have used. It has the history, goals, the specification, and lots of good examples. The VRML Sourcebook is like a VRML bible. It explains each node in deep detail, has hundreds of examples, and teaches the technical basis for the use of the language. Buy it second and study it carefully.

Have Fun
It is attractive, and it shows in the world.