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by Jim O'Donnell
Netscape
plug-in module that adds VRML browsing capability The advent of the World Wide Web (WWW), the HyperText
Markup Language (HTML), and Web
browsers capable of viewing HTML
documents including text, graphics,
and sound revolutionized the Internet.
Previously, the most common way of exchanging information was through e-mail
and Usenet
discussion groups. Because these methods could handle text only, the only
way to exchange graphics,
sound, or other binary information was for the sender to encode it and
the receiver to decode it. HTML
and the WWW changed this process by enabling you to create true multimedia
information sites on the Internet, offering real-time display and exchange
of text, graphics, sound, and other information.
The next big step beyond HTML
for information distribution on the Internet
may be the Virtual Reality Modeling Language (VRML). HTML's
hypertext links and the Web
browsers that make use of them create an essentially two-dimensional interface
to Internet
information. VRML expands this interface by allowing the creation of three-dimensional
worlds on the WWW, offering a much more natural way of presenting information.
VRML, the Virtual Reality Modeling Language, is an authoring standard,
currently defined at version 1.0, for creating three-dimensional documents
on the World
Wide Web. These documents create VRML
worlds that a user can navigate in and around using the capabilities of
a VRML-compatible browser. The current standard is file-based, involving
the transfer of 3-D scenes to the local computer-VRML source files usually
have a .wrl extension-after which all navigating through the scene is done
there. And, like HTML documents, VRML
worlds can contain links to other documents, graphics,
text, HTML
documents, or other VRML
worlds.
Freeware,
shareware,
and commercial
VRML tools are becoming widely available.
Like HTML, VRML is a fast-evolving standard for conveying information over the
Included with the Windows WebFX VRML browser, a plug-in module for Netscape Navigator 2.0 that is discussed later in this chapter, is a series of sample VRML worlds. To get a feel for what navigating around a VRML world is like and how it is different from regular HTML, you look at a simple VRML world in this chapter.
Figure 17.1 shows a sample VRML
world called Netscape.wrl, which, when loaded, shows an up-close view of
the familiar Netscape "N." After you install the WebFX plug-in,
Netscape automatically calls WebFX when a VRML world is loaded. (You know
it has been called successfully if you see the WebFX Navigation Bar at
the bottom of the browser window.) At this point, this world looks like
an HTML imagemap. The pointer even turns into a hand pointer when you move
it over the "N," indicating the presence of a hypertext link.
However, you can navigate around this three-dimensional world.
When you enter this sample VRML world, you see the familiar Netscape "N."
WebFX beginners can click the ? (question mark) WebFX button to turn on the Heads up display. Then, when you click the fly button, the display shown in figure 17.2 appears, indicating how to navigate around while you're in WebFX fly mode.
If you turn on the Heads up display, WebFX gives you hints about how to navigate the VRML world.
The quickest way to show the three-dimensional nature of the VRML
world at this point is to press and hold down the Z key, which is used
in fly mode to thrust backward. You quickly see the Netscape "N"
world recede into the distance, as shown in figure
17.3. The star field in this figure is a background image allowed by
VRML.
By pressing Z to thrust backward, you can move away from "Netscape world."
After you move some distance from the Netscape world, you can reverse course and approach it again by pressing the A key to thrust forward. Using this key, you can retrace the steps from where you began to thrust backward-you can also keep going to get a much closer view of the Netscape "N" (see fig. 17.4). You can even continue to thrust forward until you are past the "N," in which case you see only the star field background. At this point, you can turn around by pressing the right- or left-arrow key, and you actually move behind the "N" world (see fig. 17.5).
By pressing A to thrust forward, you can move right up to the Netscape "N." You can even move through and beyond it!
You can even move past the object and turn around to see it from behind.
It's easy to get lost in a VRML world sometimes. If that happens in WebFX, right-click the screen and choose Viewpoints,
Because the WebFX VRML browser is a Netscape plug-in, you might suspect
that, just as with an HTML document, you can link together VRML worlds
using hypertext links. You can even interchangeably link VRML worlds and
HTML documents! Other VRML
browsers offer similar capability, whether they are Web browser plug-ins,
helper applications, or stand-alone applications.
In this chapter's sample Netscape world, for instance, when you place
the pointer on the "N," the pointer turns into the hand pointer,
indicating the presence of a hypertext link. As shown in figure
17.6, the hand pointer and a label for the hypertext
link, which appears in the upper left, indicate where the link will take
you. In the case of this Netscape world, as you might expect, clicking
on the link takes you to the familiar Netscape HTML home page.
Just as when using new HTML enhancements, if you would like to add VRML content to your Web pages, you should keep in mind that not everyone has the necessary software to view it. Therefore, you should also convey the information included in your VRML using conventional means.
When you move the pointer over an object that is a hypertext link,
such as an HTML anchor, it turns into the hand pointer, and a URL
label for the link appears in the upper-left corner of the window.
In many ways, VRML is an extension of HTML;
the source code for HTML
documents and code for VRML
worlds are very different, but the concepts are similar. The differences
between the two lie in the fact that HTML documents are two-dimensional,
whereas VRML worlds are three-dimensional. An HTML document is like a bulletin
board, where text and graphics
can be displayed, and each can also represent a hypertext
link to another place in the document, or another document entirely. On
the other hand, a VRML world is more like a room (or world, I suppose,
if it's big enough) filled with three-dimensional objects. Because of the
three-dimensional nature of the VRML world, you can navigate around and
see objects from all sides. In VRML, like HTML, each of these objects can
also be a hypertext
link.
With a VRML-compatible Web browser, users can navigate back and forth
between HTML
documents and VRML
worlds with no additional steps. This compatibility is achieved either
by means of a plug-in module such as with WebFX and Netscape Navigator,
by setting up a VRML browser as a helper app for a Web browser, or by using
a stand-alone VRML browser that also supports HTML. Inside an HTML document,
if there is a hypertext link to a VRML world, it will be loaded and the
Web browser placed into a VRML browsing mode. Conversely, HTML
links from a VRML
world will lead back to conventional web
page viewing.
Just as with HTML documents, VRML
worlds are defined by VRML
source code. However, as you might imagine from the fact that VRML worlds
are three-dimensional, the source code is likely to be much more complex.
Figure 17.7 shows the top of the VRML
source file for the Netscape
world. The VRML
language is much more like C/C++ than it is like HTML.
VRML
"worlds" are defined by VRML
source code as shown here.
Many tools are currently being written to allow HTML
authors to create Web
pages and documents more easily. You can, however, create fairly sophisticated
Web pages programming directly in HTML. Because of the complexity of VRML,
however, it would be very difficult to do the same-to create a VRML world
by directly writing VRML code. Consider the Netscape world, which consists
of only a few objects-the Netscape "N," the sphere upon which
it rests, and the "glow" around them. The source code to describe
the Netscape "N" is partially shown in figure
17.8. Even a relatively simple object like the "N" is described
by a long series of coordinates. Programming this object directly would
be very difficult.
VRML
3-D objects, such as the Netscape "N," are defined by the coordinates
of the lines that make up the object.
To be able to create VRML worlds, you need to use a VRML authoring tool
for creating VRML 3-D objects and building them into a world. Libraries
of VRML objects are also available on the Internet.
A variety of tools for viewing and creating VRML worlds-freeware, shareware,
and commercial-has begun to appear. Because of the relative infancy of
the VRML version 1.0 standard, most of these products are still in the
beta
test stage and are available for at least trial use through the Internet.
VRML
tools are primarily being developed for two platforms: Windows (3.1, Windows
for Workgroups, 95, and NT) and UNIX (primarily SGI and Sun) machines.
The following are some of the VRML browsers currently available, along with the platform for which they are made, and where on the WWW to look for more information:
VRML
browser is a plug-in module for Netscape
Navigator that allows it to act as an integrated part of Netscape. Paper
Software, the makers of WebFX, are also planning to release a product called
WebFX
Explorer, which will be a stand-alone VRML
browser. WebFX runs under any flavor of Windows. VRML
browser is available for the SGI and Sun
UNIX platforms. The VRML Repository, whose URL is shown at the end of this chapter, is an excellent resource for finding the latest VRML tools and examples available.
VRML
worlds can be considerably more complex than HTML
documents, which makes sense considering that they are three-dimensional
models. A full discussion of creating VRML
worlds would require a book in itself, but in this chapter you go over
the types of tools that you are liable to require. Later in the chapter,
you find a simple example of creating a VRML world using Fountain, by Caligari
Software.
3-D
VRML objects is to convert them from other programs and other formats.
You can find utilities that will convert for several different kinds of
3-D objects. To get a better feel for what using a VRML browser is like, you install and try out one of them, WebFX by Paper Software, in the following sections.
The version of WebFX used herein is the WebFX plug-in for Netscape
Navigator 2. To install this plug-in, follow these steps:
Netscape
Navigator plug-in module, and automatically runs when you encounter a VRML
source file when using Netscape. The WebFX plug-in is usually meant for a specific version of
When WebFX has successfully installed, you get a dialog box similar
to this one. WebFX now automatically runs when a VRM
source file is encountered when using the Netscape
Navigator.
WebFX offers three different modes for navigating around and through
a three-dimensional VRML
world: walk, fly, and point. Other VRML
browsers may have different means of navigation-the
VRML source file defines the layout of the world, but the browser dictates
how you travel through it.
To get some help in remembering what actions work in each mode, click
the ? (question mark) WebFX
Navigation Bar button, which enables the Heads up display. If you then
click the walk button, you have the following navigation options:
crosshairs
are enabled in the Heads up display, they appear at the destination point.
keyboard
arrow keys act just as a left-drag of the mouse
cursor does in the appropriate direction. When you place WebFX in fly mode, the mouse
and keyboard
actions change to the following:
keyboard
arrow keys act just as a left-drag of the mouse
cursor does in the appropriate direction. The last navigation
mode of WebFX, point mode, allows you to navigate the VRML worlds as follows:
VRML
object upon which the cursor is positioned, and if that point is also a
hypertext
link, it causes Netscape Navigator and/or WebFX to jump to it. keyboard
arrow keys act just as a left-drag of the mouse
cursor does in the appropriate direction.
Troubleshooting
I've loaded a VRML world, and I can't see anything! What should I do?
Sometimes the initial viewpoint for a VRML world is poorly chosen, or you may have navigated yourself around until you are lost. In this case, the best way to try to find your way, in any navigation mode, is to do a right-drag, holding down the right mouse button and moving the pointer around to rotate the entire VRML world. Usually, you will be able to get the actual objects into view this way, and you can then use the navigation means discussed above to move in closer.
WebFX allows you to customize its behavior in several different ways. This customization is achieved using a pop-up menu and submenus that first appear when you right-click. The main pop-up window shown in figure 17.10 then appears.
Right-clicking in the VRML
screen opens a pop-up menu that you can use to configure WebFX. The Entry
View selection under the ViewPoints submenu returns you to where you entered
the VRML world.
Each of the six entries shown in the main pop-up window gives you different options for customizing WebFX. The following describes the most important submenus, but you should feel free to experiment with these and the other options to get a feeling for what you can do with WebFX.
VRML
world has been downloaded to your computer, the navigation
through that world is handled locally. Because VRML worlds can be quite
complex, this process is sometimes kind of slow, particularly on older
computers. If you find this to be the case on your computer, you can adjust
the level of detail by using this submenu. By switching from Solid to Wireframe
or Point Cloud, you decrease the complexity of the image and may improve
the response time (see fig. 17.11). WebFX allows you to control how much detail is shown in the three-dimensional image.
If you are using a slower computer, you can improve the performance of WebFX by changing the amount of detail that is shown.
The Heads up Display submenu allows you to control what information is shown in the WebFX Heads up display.
In this section, you examine an example VRML world I found while surfing
the Internet. It is a good example of an achievement with VRML
worlds that might not be as effective with a standard HTML
Web page. It also demonstrates how these two types of documents-representing
two ways of presenting information-can be effectively used in tandem.
Using Netscape Navigator 2 with the WebFX plug-in installed, I connected to the following URL:
http://esewww.essex.ac.uk/campus-model.wrl
Note the .wrl extension, denoting a VRML world source document. After
the connection was made by Netscape, the WebFX plug-in was called, the
VRML
world source was downloaded, and the image shown in figure
17.13 appeared. Although it isn't obvious, this figure shows the University
of Essex campus, as seen from a long way off.
The entry point to the University of Essex VRML world.
To get a closer look, put your WebFX in fly mode and fly in toward the VRML world. Give yourself a little bit of altitude to be able to see more of the campus buildings. As you get closer, you'll see the campus layout shown in figure 17.14.
You can fly in closer to the university and see a view of the campus.
As you learned earlier, VRML
worlds and HTML
documents can call one another interchangeably. The University
of Essex site uses this capability to not only convey the three-dimensional
layout of their campus, but also to allow visitors to learn more about
the different campus facilities. Consider figure
17.15; I placed the cursor over a building that has a hypertext
link, indicated by the presence of the hand pointer and the URL
label in the upper-left corner of the screen. Apparently, this building
is the University Library. When I double-clicked, an HTML web page was
called (see fig. 17.16), giving information about the library.
By placing the pointer over a given building and clicking...
Fig. 17.16
...you can jump to an HTML document with information about it.
Because the VRML world is a three-dimensional model, you can look at it from any angle, including from below (which isn't very helpful) and from above, as shown in figure 17.17, giving you a useful map of the University of Essex campus.
You can even fly up high enough and look down to get an aerial map of the campus.
Discussing VRML authoring would take a whole book, but we'll take a quick look at what it would entail here. To do so, use Caligari Software's Fountain.
Unless you do three-dimensional modeling for a living, you may find that creating VRML worlds is not the easiest thing in the world. To improve your productivity and the ease with which you arrive at your final product, it's probably a good idea to sketch out what you want your world to look like on paper before diving into Fountain or another VRML authoring program.
See Special Edition Using VRML
To install Fountain, follow these steps:
When Fountain has successfully installed, you get a dialog box similar to this one.
Now you're ready to create a simple VRML world using Fountain.
To create a simple world with one object and a hypertext link, follow these directions:
After selecting the Text Primitive button, you can type the desired text.
With the text object selected, by selecting the Sweep
button, you can make the text three-dimensional.
You can attach a URL link to any VRML object. This link can point to an HTML document.
At this point, save the document by choosing File, Scene, Save. Use
the file name jod.wrl. To see if you were successful, try to load this
file using Netscape Navigator with the WebFX plug-in module installed.
You then see the screen shown in figure 17.22.
You can see that the hypertext link is there-when you move the cursor over
the text object, it turns into a hand pointer and the URL
label appears in the upper-left corner. Because this model is three-dimensional,
you can navigate around, getting closer or farther away from the objects
there, changing the viewpoint (see fig. 17.23).
You can load my simple VRML world using Netscape Navigator and view it using the WebFX plug-in.
Because this world is three-dimensional, you can move in and around
the world's objects. If you click the JOD text object, the hypertext
link takes you to my HTML home page.
This example creates multiple objects and gives an idea of how to manipulate light sources and change the color of objects. In this one, we attempt to achieve a similar effect to the Netscape "N" world shown at the beginning of the chapter.
font
selection dialog box shown in figure 17.25.
First, you create a sphere to be your "world." The 3-D arrow points to the current object.
Right-clicking on the Text Primitives button allows you to pick your font and font size.
After typing in the letters JOD, you can hit the Sweep button to create the 3-D look.
You can move the JOD on top of your "world," even embedding it in the top.
The Paint
Faces button brings up these panels, giving you options for what color
and style to use to paint an object.
After painting your world, you can adjust where and what color the light sources are.
Moving the light source in front of your "world" brightens its appearance.
You can save this world as a WRL file.
You can view this sample world using the WebFX plug-in for Netscape Navigator.
By navigating around this sample world, one of the hazards of working in three dimensions becomes apparent. As shown in figure 17.33, you have to remember to work with all sides of an object-when you are coloring objects, for instance, be sure to get all sides!
You can see one of the effects of working in three dimensions-I didn't paint the back of my world!
After you have your system set up to view VRML documents, you'll want to start cruising the Internet and the World Wide Web to see what VRML resources and worlds are available. The list is growing every day. Following are a few of the bigger sites that will direct you to many other VRML resources-browsers, authoring tools, worlds, and object libraries:
directory
of many VRML worlds located at Mesh
Mart also maintains a Web
site of many VRML resources, including browsing and authoring tools and
VRML worlds at VRML
Web page at Silicon
Graphics is very active in VRML
development. A site with information about their WebSpace products is located
at
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