Contours

Contour lines, also called ink lines, are used in cartoon animation to provide visual cues to distinguish objects and accentuate their shape, illumination, and spatial relations. Contour rendering in the mental ray rendering software supplements standard color rendering. It works by making decisions during rendering about where and how contour lines should be placed, and then, during postprocessing, drawing contours based on the results. Drawing can take place on top of the rendered color image, or in a blank color frame buffer (if only the contours are desired), or to a PostScript file. All stages of contour rendering are programmable with shaders.