Recent advances in computational power and I/O technology have increased users’ sense of the immediacy and reality of computer-based simulations. These advances make possible virtual reality (VR), computer-generated environments that users can experience and manipulate more or less as they do the real world. VR offers an effective way to train workers in complex environments, a rich operator interface for many artificial systems, and a powerful modality for entertainment and recreation.

Roehl’s book is an excellent introduction to the basic concepts of VR, together with a surprisingly rich set of software tools for experimenting with VR on 80386 and 80486 DOS-based computers. Although the software tools come from several different authors, Roehl has integrated them and provided lucid examples and documentation, giving the user a powerful VR sandbox at a bargain price.

The first four chapters introduce VR concepts. Chapter1, “Virtual Reality,” describes the basic input, output, and networking technologies that support VR. Chapter 2, “What Makes a World Interesting?” develops 15 “commandments” that succinctly capture principles of visual and auditory reality, animation, and psychological challenge in virtual worlds. Chapter 3, “World Building from the Top Down,” outlines a series of design questions that world builders must resolve, such as the actions that are supported, the objects in the world and their behavior, and the operation of the human-machine interface. Chapter 4, “World Building from the Bottom Up,” is a simple introduction to computer graphics, including coordinate systems, polygon-based objects, and rendering algorithms.

The next five chapters are user manuals for the various programs that come on the diskette included with the book. Chapter 5, “Using VRVIEW,” describes the user interface of the viewing component of REND-386. Chapter6, “Creating Objects,” reviews a number of file formats for objects in virtual worlds. Next, it describes in detail the PLG format supported by VRVIEW. Finally, this chapter discusses how to create PLG files by hand, with custom programs (using examples in C), and using several tools included on the diskette: a fractal generator, a Lindenmayer generator, and the OGRE scripting language. Chapter 7, “Using NorthCAD-3D,” introduces another included tool, a remarkably rich CAD program that offers yet another way to generate PLG files. Chapter 8, “Assembling Worlds,” is a tutorial on the WLD files that a world builder uses to tell VRVIEW what objects are in the world, where they are located, and what cameras and lighting conditions to install. Chapter9, “Programming Virtual Worlds,” discusses three ways to add behavior to PLG-based objects in VRVIEW: a simple state machine language, a simple object-oriented language derived from C++ and called Bob, and programs written in C or C++.

The next five chapters walk the reader through example virtual worlds, all of which are included on the diskette. “The Maze,” covered in chapter 10, places the user in a maze. “Tag,” covered in chapter 11, produces a checkerboard inhabited by animated objects that play a game of tag. Chapter 12 describes “The Museum," which contains a number of animated exhibits. "The Haunted Mansion," described in chapter 13, invites the user to explore a haunted house in which various events depend on user actions (such as acquiring and using a key to open doors). Chapter 14 presents “World Trade Center,” which places the user in the role of a firefighter responding to the World Trade Center bombing.

An afterword gives both literature references and Internet sources for further information on VR. Eight appendices provide technical details, including the full syntax of WLD files (Appendix A) and VRVIEW configuration files (Appendix B) and the VRLIB library, accessible through C++ programs and (in large measure) through Bob programs. Appendix D describes the included conversion programs that permit users to generate PLG files from other common CAD file formats. Appendix E is a quick reference to the NorthCAD-3D program. Appendices F and G are synopses of VRVIEW’s State Machine Language and the syntax of Bob, respectively. Appendix H introduces the basic principles of stereoscopic viewing, which VRVIEW supports.

Throughout the book, Roehl encourages the reader to use C++, provides many examples that are compatible with  Borland  compilers, and includes the source code for numerous file conversion utilities and even for VRVIEW itself (though not for the REND386 libraries on which it rests). All the examples except the maze can be executed using only the tools contained in the book, however.

The book’s style is clear and requires only high school math and a basic understanding of programming. The programs assume a fair understanding of MS-DOS, however. README files on the diskette cover most of the inevitable discrepancies between the programs as described in the book and as furnished in executable form. There are a few glitches. For example, the L-system examples in chapter6 include characters that are not defined in the syntax of L-systems outlined in the text, and the NorthCAD-3D program does not properly create new files as presumed by the text. Such details might trip up a novice. For someone with modest PC experience and curiosity about VR, however, this book provides outstanding value for an extremely modest price.