Cel shading


Cel shading or toon shading is a type of non-photorealistic rendering designed to make 3D computer graphics appear to be flat and hand-drawn by using less shading color instead of a shade gradient or tints and shades. A cel shader is often used to mimic the style of a comic book or a cartoon and/or give the render a characteristic paper-like texture. There are similar techniques that can make an image look like a sketch, an oil painting or an ink painting. Though the end result of cel-shading has a very simplistic feel like that of hand-drawn animation, the process is complex. The name comes from cels, clear sheets of acetate which are painted on for use in traditional 2D animation.

Basic process

The cel-shading process starts with a typical 3D model. Where cel-shading differs from conventional rendering is in its non-photorealistic shading algorithm. Conventional smooth lighting values are calculated for each pixel and then quantized to a small number of discrete shades to create the characteristic "flat look", where the shadows and highlights appear as blocks of color rather than being smoothly mixed in a gradient.

Outlines

Wireframe method

Black ink outlines and contour lines can be created using a variety of methods. One popular method is to first render a black outline, slightly larger than the object itself. Back-face culling is inverted and the back-facing triangles are drawn in black. To dilate the silhouette, these back-faces may be drawn in wireframe multiple times with slight changes in translation. Alternatively, back-faces may be rendered solid-filled, with their vertices translated along their vertex normals in a vertex shader. After drawing the outline, back-face culling is set back to normal to draw the shading and optional textures of the object. Finally, the image is composited via Z-buffering, as the back-faces always lie deeper in the scene than the front-faces. The result is that the object is drawn with a black outline and interior contour lines. The term "cel-shading" is popularly used to refer to the application of this "ink" outlining process in animation and games, although originally the term referred to the flat shading technique regardless of whether the outline was applied.
The Utah teapot rendered using cel shading:
  1. The back faces are drawn with thick lines
  2. The object faces are drawn using a single color
  3. Shading is applied
Steps 2 and 3 can be combined using multitexturing.

Edge-detection method

In video games

The Dreamcast game Jet Set Radio, revealed at the 1999 Tokyo Game Show, drew media attention for its cel-shaded style. It used cel-shading for its characters and its vibrant visual style has had a lasting influence on the use of cel-shading in video games. Since the early 2000s, many notable video games have made use of this style, such as Cel Damage, The Legend of Zelda: The Wind Waker and Ōkami.
Cel shading, in contrast to other visual styles such as photorealism, is often used to lend a more artistic or fantastical element to a video game's environment. In developing Ōkami, director Hideki Kamiya described his vision for the game's graphics: "I wanted to create a game with the natural beauty of the Japanese countryside... to make a world that was glistening and beautiful." Producer Atsushi Inaba recalls in a 2004 interview that Clover Studios had "abandoned the realistic style" for Ōkami as they became inspired by traditional Japanese art.
Game studios might choose a style such as cel shading in their development for reasons beyond artistic vision. Cel shaded graphics are usually simple in visual information, which can be useful in some applications. In the case of The Legend of Zelda: The Wind Waker, developer Satoru Takizawa states that using this style allowed to "represent the mechanisms and objects for puzzles in a more easy-to-understand way." Takizawa also argues that photorealistic graphics, in contrast, would have "had the adverse effect of making information difficult to represent game-wise."

Lists of cel-shaded media

Film

  • The Great Mouse Detective, a 1986 American animated film based on "Basil of Baker Street" by Eve Titus and Paul Galdone.
  • Technological Threat, a 1988 American animated short made by Brian Jennings and Bill Kroyer and was produced by Kroyer Films.
  • Oliver & Company, a 1988 American animated musical adventure film based on the Charles Dickens novel Oliver Twist.
  • The Little Mermaid, a 1989 American animated musical fantasy film based on the 1837 Danish fairy tale of the same name by Hans Christian Andersen.
  • DuckTales the Movie: Treasure of the Lost Lamp, a 1990 American animated adventure fantasy film based on the animated television series DuckTales.
  • FernGully: The Last Rainforest, a 1992 animated musical fantasy film directed by Bill Kroyer in his feature directorial debut.
  • Tom and Jerry: The Movie, a 1992 American animated musical comedy film based on the characters Tom and Jerry created by William Hanna and Joseph Barbera.
  • The Lion King, a 1994 American animated musical coming-of-age drama film produced by Walt Disney Feature Animation and released by Walt Disney Pictures.
  • Felidae, a 1994 German adult animated mystery film directed by Michael Schaack, written by Martin Kluger, Stefaan Schieder and Akif Pirinçci, and based on Pirinçci's 1989 novel of the same name.
  • The Rugrats Movie
  • Tarzan, a 1999 American animated adventure film based on the 1912 story "Tarzan of the Apes" by Edgar Rice Burroughs.
  • The Iron Giant, a 1999 American animated science-fiction film directed by Brad Bird and based on the 1968 novel The Iron Man by Ted Hughes.
  • Fantasia 2000, a 1999 American animated musical anthology film.
  • Titan A.E.
  • The Adventures of Rocky and Bullwinkle
  • Help! I'm a Fish, a 2000 Danish-German-Irish traditionally animated science fantasy musical film.
  • Rugrats in Paris: The Movie
  • The Land Before Time VII: The Stone of Cold Fire, a 2000 American direct-to-video animated adventure musical drama and the seventh film in The Land Before Time series, produced and directed by Charles Grosvenor.
  • Osmosis Jones, a 2001 American live action/animated buddy cop comedy film.
  • The Little Polar Bear, a 2001 German animated film based on Hans de Beer books.
  • Spirit: Stallion of the Cimarron, a 2002 American animated Western film.
  • Lilo & Stitch, a 2002 American animated science-fiction comedy-drama film.
  • Hey Arnold!: The Movie
  • Treasure Planet a 2002 American animated science-fiction adventure film.
  • Rugrats Go Wild
  • Scary Godmother: Halloween Spooktakular, a 2003 Canadian animated television special produced by Mainframe Entertainment and based on a stage adaptation of the first entry in the Scary Godmother series of books by Jill Thompson.
  • Stitch! The Movie, a 2003 American direct-to-video animated science fiction comedy film
  • Brother Bear, a 2003 American animated musical fantasy comedy-drama film.
  • Hot Wheels: World Race, a 2003 animated direct-to-video film.
  • The Lion King 1½, a 2004 American animated direct-to-video musical comedy film directed by Bradley Raymond, produced by Disneytoon Studios and released on February 10, 2004. The third installment in the Lion King trilogy, the film is both a prequel and sidequel to The Lion King, focusing on the supporting characters Timon and Pumbaa. A majority of the voice cast from the first film returns to reprise their roles, including Nathan Lane and Ernie Sabella as the voices of Timon and Pumbaa, respectively. The film's structure is inspired by Tom Stoppard's Rosencrantz and Guildenstern Are Dead, a tragicomedy that tells the story of Hamlet from the point of view of two minor characters. The Lion King 1½ received generally positive reviews from critics.
  • Appleseed, a 2004 Japanese animated film.
  • Mickey, Donald, Goofy: The Three Musketeers, a 2004 American animated direct-to-video musical adventure film based on the film adaptations of the 1844 novel The Three Musketeers by Alexandre Dumas and the Mickey Mouse film series by Walt Disney and Ub Iwerks.
  • Lilo & Stitch 2: Stitch Has a Glitch, a 2005 American direct-to-video animated science fiction comedy-drama film produced by the Australian office of Disneytoon Studios.
  • Kakurenbo, a 2005 Japanese anime short film written and directed by Shuhei Morita.
  • Scary Godmother: The Revenge of Jimmy
  • Stuart Little 3: Call of the Wild, a 2005 American animated comedy film.
  • Curious George
  • Leroy & Stitch, a 2006 American animated science fiction comedy television film produced by Walt Disney Television Animation.
  • The Simpsons Movie, a 2007 American animated comedy film based on the Fox animated sitcom The Simpsons by Matt Groening.
  • Fear of the Dark, a 2007 French black-and-white animated horror anthology film written and directed by several notable comic book creators and graphic designers.
  • Garfield Gets Real, a 2007 American animated adventure comedy film based on the comic strip Garfield.
  • Nak
  • Laura's Star and the Mysterious Dragon Nian
  • Tangled, a 2010 American animated musical fantasy comedy film produced by Walt Disney Animation Studios and loosely based on the German fairy tale Rapunzel in the collection of folktales published by the Brothers Grimm.
  • Laura's Star and the Dream Monsters
  • The Painting
  • Padak
  • Arjun: The Warrior Prince, a 2012 Indian animated action film.
  • Paperman, a 2012 American black-and-white computer-cel animated short film.
  • Sofia the First: Once Upon a Princess
  • The Lost 15 Boys: The Big Adventure on Pirates' Island, a 2013 animated adventure film directed by Xiaohan, Mao Qichao, Ba Yunfeng, Zhang Bing and Ryūtarō Nakamura, based on the novel Two Years' Vacation by Jules Verne.
  • The Dam Keeper, a 2014 American animated short film directed by Robert Kondo and Daisuke Tsutsumi.
  • Team Hot Wheels: The Origin of Awesome!
  • Feast, a 2014 American 2D/3D hybrid animated romantic comedy short film.
  • Khail Girban's The Prophet, a 2014 computer cel animated film.
  • Jungle Shuffle
  • The Peanuts Movie
  • Louise by the Shore
  • Rabbit School: Guardians of the Golden Egg, a 2017 German animated adventure comedy film directed by Ute von Münchow-Pohl from the screenplay by Katja Grübel and Dagmar Rehbinder, based on the 1924 German children's novel Die Häschenschule , written by Albert Sixtus and illustrated by Fritz Koch-Gotha.
  • Zombillenium, a 2017 animated film directed by Arthur de Pins and Alexis Ducord, based on the comic series of the same name.
  • Mutafukaz: Operation Blackhead, a 2017 crime short film that became the basis for the comic book for the same name produced by Run.
  • Batman Ninja
  • White Fang
  • Underdog
  • Dilili in Paris
  • Pachamama
  • Spider-Man: Into the Spider-Verse
  • I Lost My Body, a 2019 French adult animated fantasy drama film directed by Jérémy Clapin, based on the novel Happy Hand by Guillaume Laurant.
  • Raggie
  • Tom & Jerry
  • The SpongeBob Movie: Sponge on the Run
  • The Mitchells vs. the Machines
  • Far from the Tree, a 2021 American animated short film written and directed by Natalie Nourigat and produced by Ruth Strother.
  • Opal
  • The Bad Guys
  • Chip 'n Dale: Rescue Rangers
  • Entergalactic
  • Batman and Superman: Battle of the Super Sons
  • Puss in Boots: The Last Wish
  • Justice League x RWBY: Super Heroes & Huntsmen
  • Spider-Man: Across the Spider-Verse
  • Nimona
  • Teenage Mutant Ninja Turtles: Mutant Mayhem, a 2023 animated superhero film directed by Jeff Rowe, co-directed by Kyler Spears and based on the Teenage Mutant Ninja Turtles characters created by Peter Laird and Kevin Eastman.
  • Babylon 5: The Road Home
  • Once Upon a Studio, a 2023 American live-action/animated fantasy comedy crossover short film.
  • Mars Express, a 2023 French animated science fiction thriller film directed by Jérémie Périn, and Périn's first feature film.
  • Wish, a 2023 American animated musical film.
  • Big City Greens the Movie: Spacecation, a 2024 American animated science fiction musical comedy film directed by Anna O'Brian and based on the Disney Channel animated television series Big City Greens, created by The Houghton Brothers.
  • Ultraman: Rising
  • Watchmen
  • The Wild Robot
  • Flow
  • Allah Is Not Obliged
  • Dog Man
  • Batman Ninja vs. Yakuza League
  • Predator: Killer of Killers
  • KPop Demon Hunters
  • Smurfs
  • The Bad Guys 2
  • Scarlet
  • Goat
  • Coyote vs. Acme
  • ''The Cat in the Hat''