celshaded

Cel shading, or toon shading, is a non-photorealistic rendering technique that gives 3D graphics the flat, hand-drawn appearance of traditional cel animation. It achieves this by using discrete color regions with minimal shading rather than smooth gradients, and by emphasizing bold black outlines around objects and characters.

Toon shading typically involves a lighting model that quantizes illumination into a small number of brightness levels, which are then mapped through a color ramp to create a stepped, cartoon-like shading. Outlines are produced through various methods, such as rendering inverted geometry to create silhouette lines, drawing edges in a post-processing pass, or rendering a scaled version of the model’s geometry with a dark material. Some implementations also incorporate hatch patterns or subtle textures to simulate material detail while maintaining the simplified shading.

Cel shading emerged in computer graphics as a non-photorealistic rendering approach in the late 20th century. It gained widespread attention in video games around the turn of the millennium, with notable early titles such as Jet Set Radio and The Legend of Zelda: The Wind Waker popularizing the look. In other media, the style has been used in films, television, and advertising where a stylized, graphic aesthetic is desired. More recent games, such as Borderlands, and its successors, have refined toon shading to support more complex scenes while retaining the distinctive outline-driven style.

Variants and considerations include blending toon shading with physically based rendering and post-process stylization. The approach offers a strong visual identity but can present challenges in lighting realism and asset production for some production pipelines.