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Illumination Model
{{Short description, none This article lists common shading algorithms used in computer graphics. Interpolation techniques These techniques can be combined with any illumination model: * Flat shading * Gouraud shading * Phong shading 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, microfacets, the rendering equation and subsurface scattering. Diffuse reflection Light that is reflected on a non-metallic and/or a very rough surface gives rise to a diffuse reflection. 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. This kind of reflection is especia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shader
In computer graphics, a shader is a computer program that calculates the appropriate levels of light, darkness, and color during the rendering of a 3D scene—a process known as '' shading''. Shaders have evolved to perform a variety of specialized functions in computer graphics special effects and video post-processing, as well as general-purpose computing on graphics processing units. Traditional shaders calculate rendering effects on graphics hardware with a high degree of flexibility. Most shaders are coded for (and run on) a graphics processing unit (GPU), though this is not a strict requirement. ''Shading languages'' are used to program the GPU's rendering pipeline, which has mostly superseded the fixed-function pipeline of the past that only allowed for common geometry transforming and pixel-shading functions; with shaders, customized effects can be used. The position and color ( hue, saturation, brightness, and contrast) of all pixels, vertices, and/or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Specular Highlight
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 an object and its location with respect to light sources in the scene. Microfacets The term ''specular'' means that light is specular reflection, perfectly reflected in a mirror-like way from the light source to the viewer. Specular reflection is visible only where the surface normal is oriented precisely halfway between the direction of incoming light and the direction of the viewer; this is called the half-angle direction because it bisects (divides into halves) the angle between the incoming light and the viewer. Thus, a specularly reflecting surface would show a specular highlight as the perfectly sharp reflected image of a light source. However, many shiny objects show blurred specular highlights. This can be explained by the existe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bidirectional Reflectance Distribution Function
The bidirectional reflectance distribution function (BRDF), symbol f_(\omega_,\, \omega_), is a function of four real variables that defines how light from a source is reflected off an Opacity (optics), opaque surface. It is employed in the optics of real-world light, in computer graphics algorithms, and in computer vision algorithms. The function takes an incoming light direction, \omega_, and outgoing direction, \omega_ (taken in a coordinate system where the Normal (geometry), surface normal \mathbf n lies along the ''z''-axis), and returns the ratio of reflected radiance exiting along \omega_ to the irradiance incident on the surface from direction \omega_. Each direction \omega is itself Spherical coordinate system, parameterized by azimuth angle \phi and zenith angle \theta, therefore the BRDF as a whole is a function of 4 variables. The BRDF has units sr−1, with steradians (sr) being a unit of solid angle. Definition The BRDF was first defined by Fred Nicodemus around 19 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gooch Shading
Gooch shading is a non-photorealistic rendering technique for shader, 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 Ashurst Gooch, Amy Gooch et al. at the University of Utah School of Computing and first presented at the 1998 SIGGRAPH conference. It has since been implemented in shader libraries, software, and games released by Autodesk, NVIDIA, and Valve Corporation, Valve. Process Gooch shading defines an additional two colors in conjunction with the original model color: a warm color (such as yellow) and a cool color (such as blue). The warm color indicates surfaces that are facing toward the light source while the cool color indicates surfaces facing away. This allows shading to occur only in mid-tones so that edge lines and highlights remain visually prominent. The Gooch shader is typically implemented in two passes: all objects in the scene are first drawn with the "cool t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cel Shading
Cel shading or toon shading is a type of non-photorealistic rendering designed to make 3D computer graphics appear to be flat 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 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. The name comes from ''cels'' (short for celluloid), 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 rathe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 images that effectively convey certain information via the visual channel to the human observer".Ivan Viola and Meister E. Gröller (2005).Smart Visibility in Visualization. In: ''Computational Aesthetics in Graphics, Visualization and Imaging''. L. Neumann et al. (Ed.) Technical illustrations generally have to describe and explain the subjects to a nontechnical audience. Therefore, the visual image should be accurate in terms of dimensions and proportions, and should provide "an overall impression of what an object is or does, to enhance the viewer’s interest and understanding". Types Types of communication Today, technical illustration can be broken down into three categories based on the type of communication: * Communication with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Movies
A film, also known as a movie or motion picture, is a work of visual art that simulates experiences and otherwise communicates ideas, stories, perceptions, emotions, or atmosphere through the use of moving images that are generally, since the 1930s, synchronized with sound and (less commonly) other sensory stimulations. Etymology and alternative terms The name "film" originally referred to the thin layer of photochemical emulsion on the celluloid strip that used to be the actual medium for recording and displaying motion pictures. Many other terms exist for an individual motion-picture, including "picture", "picture show", "moving picture", "photoplay", and "flick". The most common term in the United States is "movie", while in Europe, "film" is preferred. Archaic terms include "animated pictures" and "animated photography". "Flick" is, in general a slang term, first recorded in 1926. It originates in the verb flicker, owing to the flickering appearance of early films. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Video Games
A video game or computer game is an electronic game 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 generate visual feedback from a display device, most commonly shown in a video format on a television set, computer monitor, flat-panel display or touchscreen on handheld devices, or a virtual reality headset. Most modern video games are audiovisual, with Sound, audio complement delivered through loudspeaker, speakers or headphones, and sometimes also with other types of sensory feedback (e.g., haptic technology that provides Touch, tactile sensations). Some video games also allow microphone and webcam inputs for voice chat in online gaming, in-game chatting and video game livestreaming, livestreaming. Video games are typically categorized according to their hardware platform, which traditionally includes arcade video games, console games, and PC game, comp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cartoons
A cartoon is a type of visual art that is typically drawn, frequently Animation, animated, in an realism (arts), unrealistic or semi-realistic style. The specific meaning has evolved, but the modern usage usually refers to either: an image or series of images intended for satire, caricature, or humor; or a motion picture that relies on a sequence of illustrations for its animation. Someone who creates cartoons in the first sense is called a ''cartoonist'', and in the second sense they are usually called an ''animator''. The concept originated in the Middle Ages, and first described a preparatory drawing for a piece of art, such as a painting, fresco, tapestry, or stained glass window. In the 19th century, beginning in ''Punch (magazine), Punch'' magazine in 1843, cartoon came to refer – ironically at first – to humorous artworks in magazines and newspapers. Then it also was used for political cartoons and comic strips. When the medium developed, in the early 20th century, it ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Non-photorealistic Rendering
Non-photorealistic rendering (NPR) is an area of computer graphics that focuses on enabling a wide variety of expressive styles for digital art, in contrast to traditional computer graphics, which focuses on photorealism. NPR is inspired by other artistic modes such as painting, drawing, technical illustration, and animated cartoons. NPR has appeared in movies and video games in the form of cel-shaded animation (also known as " toon" shading) as well as in scientific visualization, architectural illustration and experimental animation. History and criticism of the term The term ''non-photorealistic rendering'' is believed to have been coined by the SIGGRAPH 1990 papers committee, who held a session entitled "Non Photo Realistic Rendering". The term has received some criticism: * The term "photorealism" has different meanings for graphics researchers (see "photorealistic rendering") and artists. For artists—who are the target consumers of NPR techniques—it refers to a sc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Non-metals
Nonmetallic material, or in nontechnical terms a ''nonmetal'', refers to materials which are not metals. Depending upon context it is used in slightly different ways. In everyday life it would be a generic term for those materials such as plastics, wood or ceramics which are not typical metals such as the iron alloys used in bridges. In some areas of chemistry, particularly the periodic table, it is used for just those chemical elements which are not metallic at standard temperature and pressure conditions. It is also sometimes used to describe broad classes of dopant atoms in materials. In general usage in science, it refers to materials which do not have electrons that can readily move around, more technically there are no available states at the Fermi energy, the equilibrium energy of electrons. For historical reasons there is a very different definition of metals in astronomy, with just hydrogen and helium as nonmetals. The term may also be used as a negative of the materials ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
