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About This
Book
What This
Book Contains
How to Use This Book
Getting Started
Conventions
About the Authors
Acknowledgements
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About This Book
The Annotated VRML 97 Reference Manual contains the complete
specification of the Virtual Reality Modeling Language, as of April
4,1997. In addition, throughout this book you will find a variety of
technical annotations, authoring tips, and illustrative examples. While
the VRML specification is technically accurate and precise, it is not
intended to address questions on why it is designed the way it is, what's
the best way to use it, what to avoid, or how to implement it. These
issues and more are featured throughout this book. The annotations relate
the various separate parts of VRML into a coherent whole. The contents
of this book are relevant to implementors of the VRML specifications
as well as to authors and users of VRML.
This book is not a tutorial on VRML. There are a variety of books
that teach basic and advanced VRML concepts, and serve as excellent
companions to this book (see Appendix F, Recommended
Reading).
This book does not rely on or describe any single specific implementation
of VRML, rather it presents the ideal definition of VRML and suggests
typical implementation pitfalls and difficulties to watch out for. See
Appendix E, VRML Compendium, for a summary of
the browser and authoring tools available for you to choose from.
The first chapter, Introduction, describes the
motivation, history, and basis for VRML. Chapter
2, Key Concepts, presents a technical overview of the VRML file
format and underlying architecture. This chapter introduces you to the
file format syntax and goes on to discuss a variety of important architectural
fundamentals of VRML, such as prototypes, routing, scripting, execution
model, and binding node behavior. The third chapter, Node
Reference, contains the largest and most significant aspect of the
book. It defines the syntax and semantics of every node in the specification,
as well as complete working examples for each node, and a variety of
annotations and tips. Chapter 4, Field and Event Reference, describes the syntax
and semantics of the VRML data types--fields and events. The fifth chapter,
Conformance and Minimum Support Requirements,
specifies the baseline requirements to which VRML implementations must
adhere. This chapter is useful to authors and implementors alike, as
a benchmark of which features are required in a conforming VRML application.
Appendix A, VRML Grammar Definition, provides
a precise grammar definition of the VRML file format. Appendix
B, Java Scripting Reference, describes the integration of the Java
programming language with VRML. This appendix defines the specific classes
and methods that may be invoked from a VRML Script node using Java.
Appendix C, JavaScript Scripting Reference, defines the integration
of the JavaScript scripting language with VRML. It includes a detailed
specification of the JavaScript objects and functions available to a
VRML Script node. Appendix D, Examples, includes
the revised sample files found in the VRML specification. Appendix
E, VRML Compendium, lists a variety of Uniform Resource Locators
(URLs) to VRML-related sources and topics. Appendix
F, Recommended Reading, lists a variety of books that supplement
the material contained in this book. Appendix G,
Summary of Java Scripting API, provides a quick reference to the
Java classes and methods. Appendix H, Summary of JavaScript Scripting API, provides
a quick reference to the JavaScript objects and methods.
There are several ways to use this book. First you can read Chapter 1, Introduction, and Chapter
2, Key Concepts, for an in-depth description of the fundamentals
of VRML, and use Appendix E, VRML Compendium,
to find a variety of references on VRML-related information sources.
Advanced technical readers should have no problem using these chapters
as their introduction to VRML, while novices may wish to start with
an introductory book before reading these chapters. The second way to
use this book is as an everyday reference guide. It is organized for
fast access and daily use: specification text is easily distinguished
from the annotations; and notes, tips, and examples are located in the
section containing the relevant topic. The third way to use this book
is to read the notes, tips, and examples to enhance your knowledge and
gain new insight into VRML.
The examples included in this book conform to the VRML specification
and are accurate to the best of our knowledge, but may not work in all
browsers (see the browser's release notes for supported features and
known bugs).
This book contains references to a variety of URLs. Note that it is
possible that URLs may change or become inactive after the publication
of this book, and that it may be necessary to employ a search engine
to find a more up-to-date URL.
There are only two things needed to get started with VRML: a VRML
browser and a text editor. When choosing from the wide variety of VRML
browsers available, keep in mind which system you are using, which system(s)
you expect your users to have, and the essential VRML features that
you intend to use (not all browsers support all features in the specification).
VRML files are plain text files, so you can create them using any text
editor. Most word processors can read and write text files; be sure
to "Save As" plain text. Special-purpose programming editors
are even better for editing VRML files because they support features
such as matching opening and closing braces and automatically indenting
each line.
There are also VRML authoring tools available. These range from file
converters to single-task utilities to full-fledged authoring environments.
VRML has become so popular as a three-dimensional (3D) file exchange
format that many 3D applications output VRML. File converters from most
3D formats are also readily available. Note that there is a big difference
between an authoring system that outputs VRML and one that authors
VRML. Typically, native VRML systems support more features and produce
better results, but some of the systems that output VRML are just as
good.
1. There are three types of annotations in the book: technical notes,
authoring tips, and examples. Each annotation type is labeled with an
icon in the margin for easy recognition:
| TIP:
This is an example of an authoring tip. Tips range from suggestions
on proper usage to warnings on problem areas to nonobvious ideas
for combining and using VRML. |
| TECHNICAL
NOTE: This is an example technical note. It may contain historical
footnotes concerning the design of VRML, advanced technical notes,
or implementation details. These notes are typically of interest
to implementors and advanced authors. |
EXAMPLE
(click to run): This is an example of a VRML example file. Most
of the examples start with an explanatory introduction; some include
an image illustrating the results on screen. Most of the examples
are complete, but some may include "..." to imply that
valid VRML syntax goes here:
#VRML V2.0 utf8
Transform { children [
...
]}
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2. New terms, field names, and event names are printed in italic type:
A prototype is a . . .
The radius field . . .
The isActive eventOut . . .
3. Node definitions specify the complete set of events and fields
for a given node type. The parts of the definition that correspond to
the file format are given in a bold, fixed-space font, while the rest
of the definition is given in a plain, fixed-space font:
Collision {
eventIn MFNode addChildren
eventIn MFNode removeChildren
exposedField MFNode children []
exposedField SFBool collide TRUE
field SFVec3f bboxCenter 0 0 0
field SFVec3f bboxSize -1 -1 -1
field SFNode proxy NULL
eventOut SFTime collideTime
}
4. Programming interfaces, VRML file examples, and URLs are printed
in a plain, fixed-space font:
void createVrmlFromString( String vrmlSyntax
);
Cylinder { radius 3 height 5 }
http://www.aw.com
5. DEF and USE names are usually chosen as an abbreviation of the
node type and are numbered if there are more than one of the same type
in the file. For example, if an example file contains two ProximitySensors,
the first one would be named PS1 and the second one PS2:
#VRML V2.0 utf8
Transform { children [
DEF PS1 ProximitySensor {...}
...
DEF PS2 ProximitySensor {...}
...
]}
6. Background nodes have been added to most of the examples to produce
white backgrounds for printing.
7. The colors in most of the examples were chosen to be in gray scale
since the images are printed in gray scale.
8. Field values and closing braces and brackets are often combined
on one line to compress the examples in the book:
#VRML V2. utf8
Transform { children [
Sphere { radius 4 }
Cylinder { height 5 radius 3 }
Transform {
children [
...
]}]}
Acknowledgments
This book would not be possible without the dedication and help of
many people. The following is a short list of some of those people.
We cannot possibly thank everyone (although we would like to); please
forgive us if we've neglected to mention you here.
Special thanks to Paul Strauss for his pioneering efforts on Open
Inventor, which eventually led to VRML. Thanks to the rest of the Open
Inventor engineering team for laying the groundwork that VRML is based
on: Thad Beier, Alain Dumesny, Dave Immel, Paul Isaacs, Howard Look,
David Mott, Nick Thompson, and Helga Thorvaldsdóttir. Thanks
to Chris Marrin for his work on the Java and JavaScript appendices,
as well as a variety of other important areas of the VRML Specification.
Thanks to Mark Pesce and Tony Parisi for writing the first prototype
of a 3D web browser, Labyrinth, and for their tireless contribution
and dedication to VRML.
Thanks to Mitra, Kouichi Matsuda, Rodger Lea, and Yasuaki Honda for
their work on the Moving Worlds proposal and the Java appendix. Thanks
to the many unnamed people who contributed ideas and work to the VRML
Specification--you know who you are.
Thanks to Silicon Graphics, Inc., for creating a fantastic work environment
and for taking a risk on VRML.
Thanks to Mary Treseler, John Fuller, Keith Wollman, and the Addison
Wesley Longman staff for guidance and support. Thanks to our book reviewers:
Scott S. Ross, Stephen Chenney, Len Bullard, Cindy Reed-Ballreich, Jan
C. Hardenbergh, Chet Murphy, Jai Natarajan, Matt O'Donnell, David Story,
and Mason Woo. Thanks to Sam Chen and Silicon Graphics, Inc., for providing
the cover image for this book. Thanks also to Sam Chen, Silicon Graphics,
Inc. and Construct Internet Design for the O2 Out of Box Experience
images used in the color plates.
And last, but not least, thanks to the members of the www-vrml
mailing list for your ideas, passion, and hard work.
About The Authors
Rikk Carey lives in California and spends his his time on 3d graphics
stuff, his gardens, taking care of his bunny FooFoo, looking
at his guitar, and playing golf.
Gavin Bell lives in Wisconsin where he enjoys 3d graphics stuff, bicycling,
and playing with his cats Tekka and Echo.
If you wish to contact the authors:
email: Rikk Carey
email: Gavin Bell
email to both: Rikk Carey
and Gavin Bell
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