The ubiquity of computer-generated imagery around us, in movies, advertising or on the Internet is already being taken for granted and what impresses most people is the photorealistic quality of the images. Pictures, as we have often been told, are worth a thousand words and the information transported by an image can take many different forms. Many computer graphics researchers are exploring non-photorealistic rendering techniques as an alternative to realistic rendering. Defined by what it is not, non-photorealistic rendering brings art and science together, concentrating less on the...