Sketch is a small, simple system for producing line drawings of two- or
three-dimensional solid objects and scenes. It began as a way to make
illustrations for a textbook after we could find no suitable tool for this
purpose. Existing scene processors emphasized GUIs and/or photo-realism,
both un-useful to us. We wanted to produce finely wrought, mathematically-based
illustrations with no extraneous detail. The input language is reminiscent of
PSTricks, so will be easy to learn for current PSTricks users.