! The scene description read by consists of a number of keywords, each followed by a set of arguments. These keywords can ! be thought of as commands that direct rayshade to do various things, such as create objects, set the eye's position, and change an object's appearance.
— 14,36 —- surface definitions might be modified, the eye or look positions may be slightly changed, or the intensity of a light source changed.
! This chapter describes the basic operation of and some of the options that control that operation. Setting these options properly can greatly reduce rendering time, improve the quality of your images, and make you a better person.
! usually works as a filter, reading a description from the standard input and writing ! an image file to the standard output. As it is working, reports on the progress of the rendering by writing messages to the standard error.