{{Short description, none This article lists common shading algorithms used in

computer graphics Computer graphics deals with generating images with the aid of computers. Today, computer graphics is a core technology in digital photography, film, video games, cell phone and computer displays, and many specialized applications. A great de ...

Interpolation techniques

These techniques can be combined with any illumination model: *

Flat shading Shading refers to the depiction of depth perception in 3D models (within the field of 3D computer graphics) or illustrations (in visual art) by varying the level of darkness. Shading tries to approximate local behavior of light on the object's ...

Gouraud shading Gouraud shading, named after Henri Gouraud, is an interpolation method used in computer graphics to produce continuous shading of surfaces represented by polygon meshes. In practice, Gouraud shading is most often used to achieve continuous l ...

Phong shading In 3D computer graphics, Phong shading, Phong interpolation, or normal-vector interpolation shading is an interpolation technique for surface shading invented by computer graphics pioneer Bui Tuong Phong. Phong shading interpolates surface norm ...

Illumination models

Realistic

The illumination models listed here attempt to model the perceived brightness of a surface or a component of the brightness in a way that looks realistic. Some take physical aspects into consideration, like for example the

Fresnel equations The Fresnel equations (or Fresnel coefficients) describe the reflection and transmission of light (or electromagnetic radiation in general) when incident on an interface between different optical media. They were deduced by Augustin-Jean Fres ...

microfacet A specular highlight is the bright spot of light that appears on shiny objects when illuminated (for example, see image on right). Specular highlights are important in 3D computer graphics, as they provide a strong visual cue for the shape of a ...

s, the

rendering equation In computer graphics, the rendering equation is an integral equation in which the equilibrium radiance leaving a point is given as the sum of emitted plus reflected radiance under a geometric optics approximation. It was simultaneously introduced ...

and

subsurface scattering Subsurface scattering (SSS), also known as subsurface light transport (SSLT), is a mechanism of light transport in which light that penetrates the surface of a translucent object is scattered by interacting with the material and exits the surfa ...

Diffuse reflection

Light that is reflected on a

non-metal In chemistry, a nonmetal is a chemical element that generally lacks a predominance of metallic properties; they range from colorless gases (like hydrogen) to shiny solids (like carbon, as graphite). The electrons in nonmetals behave different ...

lic and/or a very rough surface gives rise to a

diffuse reflection Diffuse reflection is the reflection (physics), reflection of light or other radiation, waves or particles from a surface such that a ray (optics), ray incident on the surface is scattering, scattered at many angles rather than at just one angle ...

. Models that describe the perceived brightness due to diffuse reflection include: * Lambert * Oren–Nayar (Rough opaque diffuse surfaces) * Minnaert

Specular reflection

Light that is reflected on a relatively smooth surface gives rise to a

specular reflection Specular reflection, or regular reflection, is the mirror-like reflection of waves, such as light, from a surface. The law of reflection states that a reflected ray of light emerges from the reflecting surface at the same angle to the surf ...

. This kind of reflection is especially strong for metal surfaces. Models that describe the perceived brightness due to specular reflection include: * Phong * Blinn–Phong * Cook–Torrance (microfacets) * Ward anisotropic

Subsurface scattering

Subsurface scattering Subsurface scattering (SSS), also known as subsurface light transport (SSLT), is a mechanism of light transport in which light that penetrates the surface of a translucent object is scattered by interacting with the material and exits the surfa ...

is an indirect form of reflection where some of the light is transmitted into a semi-transparent material, scattered under the surface and bounced back out again. The light that is not absorbed by the material and bounced out through the surface again gives rise to a diffuse indirect reflection, which will illuminate the surface not only where it is lit, but also in the vicinity of where the light hits, as well as on the other side of thin parts of an object. Most

non-metals In chemistry, a nonmetal is a chemical element that generally lacks a predominance of metallic properties; they range from colorless gases (like hydrogen) to shiny solids (like carbon, as graphite). The electrons in nonmetals behave differentl ...

can transmit light to a certain degree and are therefore affected by this effect. Subsurface scattering models include: * Hanrahan–Krueger model of subsurface scattering

Non-photorealistic

Non-photorealistic illumination models don't attempt to model the perceived brightness of a surface in a realistic way, but focuses expressing certain styles. They are used for example in

cartoons A cartoon is a type of visual art that is typically drawn, frequently animated, in an unrealistic or semi-realistic style. The specific meaning has evolved over time, but the modern usage usually refers to either: an image or series of images ...

video games Video games, also known as computer games, are electronic games that involves interaction with a user interface or input device such as a joystick, game controller, controller, computer keyboard, keyboard, or motion sensing device to gener ...

movies A film also called a movie, motion picture, moving picture, picture, photoplay or (slang) flick is a work of visual art that simulates experiences and otherwise communicates ideas, stories, perceptions, feelings, beauty, or atmosphere ...

technical illustration Technical Illustration is illustration meant to visually communicate information of a technical nature. Technical illustrations can be components of technical drawings or diagrams. Technical illustrations in general aim "to generate expressive i ...

s, and include: * Cel shading *

Gooch shading Gooch shading is a non-photorealistic rendering technique for shading objects. It is also known as "cool to warm" shading, and is widely used in technical illustration. History Gooch shading was developed by Amy Gooch et al. at the University of ...