Cel-Shaded Animation

Cel-shaded animation is a type of non-photorealistic rendering designed to make computer graphics appear to be hand-drawn. It is often used to mimic the style of a comic book or cartoon. It is a somewhat recent addition to computer graphics, most commonly turning up in video games. There are also some television shows that use the cel-shading style. These shows include Family Guy, Futurama, Fairly Oddparents, The Simpsons, and many more.

Most of the time the cel-shading process starts with a typical 3D model. In order to draw black ink lines outlining an object's contours, the back-face culling is inverted to draw back-faced triangles with black-colored vertices. The vertices must be drawn many times with a slight change in translation to make the lines thick. This produces a black-shaded silhouette. The back-face culling is then set back to normal to draw the shading and optional textures of the object. The result is that the object is drawn with a black outline.

The result is that the object is drawn with a black outline and interior contour lines. Popularly, this "ink" outline applied to animation and games is what’s called cel shading, while originally the term referred to the shading technique, regardless of whether outline is being applied or not.