\chapter*{Preface}
\addcontentsline{toc}{chapter}{Preface}

{\em Rayshade} is a program for creating ray-traced images.
It reads a description of a scene to be
rendered and produces a color image corresponding to the
description.
{\em Rayshade} was designed to make it easy to
create nice pictures.
It was also meant to be flexible, easy to modify,
and relatively fast.

The first version of \rayshade was written in 1987-1998 at
Princeton University with help and encouragement from David Dobkin
and David Hoffman.  That version was heavily based on a public-domain
``introductory'' ray tracer written by Roman Kuchkuda.
Changes to \rayshade from that point until version 4.0 were
evolutionary in nature.
The current version is to a large extent a re-write,
and an attempt has been made to remove some of the fundamental
problems present in previous incarnations.

I wish to thank the many people who have made
contributions to the development of {\em rayshade} during the past four years.
Thanks to Marc Andreessen, Ray Bellis, Dominique Boisvert, William Bouma,
Allen Braunsdorf, Jeff Butterworth, Nick Carriero, Nancy Everson, Tom Friedel,
Robert Funchess, David Gelernter, Mike Gigante, Ed Herderick, John Knuston,
Raphael Manfredi, Lee Moore, Dietmar Saupe, Brian Wyvill,
and everybody else for their bug-fixes, suggestions, input files,
encouragement, support, and other feedback.

David Dobkin first suggested that an extensible
ray tracer would be a worthwhile project.  Gavin Bell, David
Hoffman, Lefteris Koutsofios, and Steven North
were the first users of the original \rayshade, and their feedback
showed that the project might indeed have a future.
In the Fall of 1988,
Przemyslaw Prusinkiewicz encouraged me
to develop \rayshade further, and was, as always, full of ``insanely
great'' ideas.  The resulting version of \rayshade was released
on UseNet in 1989.  Allan Snider was particularly helpful in
finding bugs in version 3.0 and in making valuable suggestions
as to how the program might be improved.

{\em Rashade} version 4.0
was written by Craig Kolb and Rod Bogart during 1990, with contributions
of ideas and code made by many others.
Pat Hanrahan's {\em OOGL} provided the spirit, if not the letter, of the
modularity of the version 4.0.  Thanks to Pat and to Mark VandeWettering
for the ``net tracer'' conversations and for the inspiration to do something
to clean up {\em rayshade}.
Eric Haines saved the day on more than one occasion by suggesting
improvements, finding bugs, and saying nice things about \rayshade
when I was all but ready to throw in the towel.
Robert Skinner was kind enough to provide the {\em Noise()}, {\em DNoise()},
and other texturing functions and to allow them to be redistributed.
Mark Podlipec provided the blob object and torus object, which uses
Jochen Schwarze's cubic and quartic root-finding functions.

Major Thanks to Rod Bogart for being willing to take the plunge and
play such a large role in the development of version 4.0.

Finally, I am most grateful to Benoit Mandelbrot for his
continued support and inspiration.

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C. K. \\
February 13, 1991
}
\end{flushright}
