World Library  
Flag as Inappropriate
Email this Article

Cel shading

Article Id: WHEBN0000697990
Reproduction Date:

Title: Cel shading  
Author: World Heritage Encyclopedia
Language: English
Subject: Computer animation, Malaysian animation, Dark Chronicle, 3D computer graphics, Rogue Galaxy
Collection: Animation Techniques, Cel-Shaded Animation, Computer Animation, Shading, Video Game Graphics
Publisher: World Heritage Encyclopedia
Publication
Date:
 

Cel shading

A representation of a space suit from The Adventures of Tintin comic Explorers on the Moon with a basic cel-shader (also known as a toon shader) and border detection.

Cel shading (often misspelled as 'cell shading') or toon shading is a type of non-photorealistic rendering designed to make 3-D computer graphics appear to be flat by using less shading color instead of a shade gradient or tints and shades. Cel-shading is often used to mimic the style of a comic book or cartoon. It is somewhat recent, appearing from around the beginning of the twenty-first century. The name comes from cels (short for celluloid), the clear sheets of acetate which are painted on for use in traditional 2D animation.[1]

Contents

  • Process 1
  • Cel shading in video games 2
  • Gallery 3
  • List of cel-shaded media 4
    • Video games 4.1
    • Commercials 4.2
    • Television 4.3
  • See also 5
  • References 6
  • External links 7

Process

The cel-shading process starts with a typical 3D model. Where cel-shading differs from conventional rendering is in its non-photorealistic illumination model. 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 more like blocks of color rather than mixed in a smooth way.

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. Backface 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 shading technique regardless of whether the outline was applied.[2]

The Utah teapot rendered using cel-shading:

The Utah Teapot rendered using cel-shading.

  1. The back faces are drawn with thick lines
  2. The object is drawn with a basic texture
  3. Shading

Steps 2 and 3 can be combined using multi-texturing (see texture mapping).

Another outlining technique is to use 2D image-processing. First, the scene is rendered (with cel-shading) to a screen-sized color texture:

Then, the scene's depth and world-space surface normal information are rendered to screen-sized textures:

A Sobel filter or similar edge-detection filter is applied to the normal/depth textures to generate an edge texture. Texels on detected edges are black, while all other texels are white:

Finally, the edge texture and the color texture are composited to produce the final rendered image:

Cel shading in video games

Cel shading became synonymous in interactive media with Jet Set Radio in 2000 for the Sega Dreamcast but it has been applied in numerous other games over the years, including more mature titles such as Cel Damage, No More Heroes and Grand Theft Auto: Chinatown Wars. Other notable examples include The Legend of Zelda: The Wind Waker, Viewtiful Joe, Ni No Kuni, Escape Dead Island, and Ultimate Spider-Man (video game).

Gallery

Two isosurfaces of the probability density of a particle in a box, rendered with cel shading. 

List of cel-shaded media

Video games

Some prominent games featuring cel shading are Jet Set Radio for the Sega Dreamcast and The Legend Of Zelda: The Wind Waker for the Nintendo GameCube. Mirror's Edge's cutscenes use a mixture of drawn characters and 3D toon shaded models, with the latter used mostly in vehicles and such.

Commercials

Television

See also

References

  1. ^ Hachigian, Jennifer. "Celshader.com FAQ". Retrieved August 2, 2005. 
  2. ^ Luque, Raul (December 2012). The Cel Shading Technique (PDF). Retrieved December 2, 2014. 

External links

  • reviewJet Set RadioIGN: . Retrieved August 4, 2005.
  • GameDev.net – Cel-Shading. Retrieved August 5, 2005.
  • sunandblackcat.com – Cel-Shading. Retrieved August 7, 2014.
  • tv tropes about cel-shading. Retrieved december 2, 2014
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.
 



Copyright © World Library Foundation. All rights reserved. eBooks from Hawaii eBook Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.