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Global Illumination
Global illumination (GI), or indirect illumination, is a group of algorithms used in 3D computer graphics that are meant to add more realistic lighting to 3D scenes. Such algorithms take into account not only the light that comes directly from a light source (''direct illumination''), but also subsequent cases in which light rays from the same source are reflected by other surfaces in the scene, whether reflective or not (''indirect illumination''). Theoretically, reflections, refractions, and shadows are all examples of global illumination, because when simulating them, one object affects the rendering of another (as opposed to an object being affected only by a direct source of light). In practice, however, only the simulation of diffuse inter-reflection or caustics is called global illumination. Algorithms Images rendered using global illumination algorithms often appear more photorealistic than those using only direct illumination algorithms. However, such images are co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Graphics Lighting
Computer graphics lighting is the collection of techniques used to simulate light in computer graphics scenes. While lighting techniques offer flexibility in the level of detail and functionality available, they also operate at different levels of computational demand and complexity. Graphics artists can choose from a variety of light sources, models, shading techniques, and effects to suit the needs of each application. Light sources Light sources allow for different ways to introduce light into graphics scenes. Point Point sources emit light from a single point in all directions, with the intensity of the light decreasing with distance. An example of a point source is a standalone light bulb. Directional A directional source (or distant source) uniformly lights a scene from one direction. Unlike a point source, the intensity of light produced by a directional source does not change with distance over the scale of the scene, as the directional source is treated as though ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ray Tracing (graphics)
In 3D computer graphics, ray tracing is a technique for modeling light transport for use in a wide variety of rendering algorithms for generating digital images. On a spectrum of computational cost and visual fidelity, ray tracing-based rendering techniques, such as ray casting, recursive ray tracing, distribution ray tracing, photon mapping and path tracing, are generally slower and higher fidelity than scanline rendering methods. Thus, ray tracing was first deployed in applications where taking a relatively long time to render could be tolerated, such as in still computer-generated images, and film and television visual effects (VFX), but was less suited to real-time applications such as video games, where speed is critical in rendering each frame. Since 2018, however, hardware acceleration for real-time ray tracing has become standard on new commercial graphics cards, and graphics APIs have followed suit, allowing developers to use hybrid ray tracing and rasterization- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photon Mapping
In computer graphics, photon mapping is a two-pass global illumination rendering algorithm developed by Henrik Wann Jensen between 1995 and 2001Jensen, H. (1996). ''Global Illumination using Photon Maps''. nlineAvailable at: http://graphics.stanford.edu/~henrik/papers/ewr7/egwr96.pdf that approximately solves the rendering equation for integrating light radiance at a given point in space. Rays from the light source (like photons) and rays from the camera are traced independently until some termination criterion is met, then they are connected in a second step to produce a radiance value. The algorithm is used to realistically simulate the interaction of light with different types of objects (similar to other photorealistic rendering techniques). Specifically, it is capable of simulating the refraction of light through a transparent substance such as glass or water (including caustics), diffuse interreflection between illuminated objects, the subsurface scattering of light in tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photon Mapping
In computer graphics, photon mapping is a two-pass global illumination rendering algorithm developed by Henrik Wann Jensen between 1995 and 2001Jensen, H. (1996). ''Global Illumination using Photon Maps''. nlineAvailable at: http://graphics.stanford.edu/~henrik/papers/ewr7/egwr96.pdf that approximately solves the rendering equation for integrating light radiance at a given point in space. Rays from the light source (like photons) and rays from the camera are traced independently until some termination criterion is met, then they are connected in a second step to produce a radiance value. The algorithm is used to realistically simulate the interaction of light with different types of objects (similar to other photorealistic rendering techniques). Specifically, it is capable of simulating the refraction of light through a transparent substance such as glass or water (including caustics), diffuse interreflection between illuminated objects, the subsurface scattering of light in tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Image-based Lighting
Image-based lighting (IBL) is a 3D rendering technique which involves capturing an omnidirectional representation of real-world light information as an image, typically using a 360° camera. This image is then projected onto a dome or sphere analogously to environment mapping, and this is used to simulate the lighting for the objects in the scene. This allows highly detailed real-world lighting to be used to light a scene, instead of trying to accurately model illumination using an existing rendering technique. Image-based lighting often uses high-dynamic-range imaging for greater realism, though this is not universal. According to Fxguide, "Almost all modern rendering software offers some type of image-based lighting, though the exact terminology used in the system may vary." Motion picture production makes use of image-based lighting, and it can be seen in movies like ''Monsters University'', ''The Great Gatsby'', and ''Iron Man 2''. One reference capture technique, sometimes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Path Tracing
Path tracing is a computer graphics Monte Carlo method of rendering images of three-dimensional scenes such that the global illumination is faithful to reality. Fundamentally, the algorithm is integrating over all the illuminance arriving to a single point on the surface of an object. This illuminance is then reduced by a surface reflectance function (BRDF) to determine how much of it will go towards the viewpoint camera. This integration procedure is repeated for every pixel in the output image. When combined with physically accurate models of surfaces, accurate models of real light sources (light bulbs), and optically correct cameras, path tracing can produce still images that are indistinguishable from photographs. Path tracing naturally simulates many effects that have to be specifically added to other methods (conventional ray tracing or scanline rendering), such as soft shadows, depth of field, motion blur, caustics, ambient occlusion, and indirect lighting. Implementa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Distributed Ray Tracing
Distributed ray tracing, also called distribution ray tracing and stochastic ray tracing, is a refinement of ray tracing that allows for the rendering of "soft" phenomena. Conventional ray tracing uses single rays to sample many different domains. For example, when the color of an object is calculated, ray tracing might send a single ray to each light source in the scene. This leads to sharp shadows, since there is no way for a light source to be partially occluded (another way of saying this is that all lights are point sources and have zero area). Conventional ray tracing also typically spawns one reflection ray and one transmission ray per intersection. As a result, reflected and transmitted images are perfectly (and usually unrealistically) sharp. Distributed ray tracing removes these restrictions by averaging multiple rays distributed over an interval. For example, soft shadows can be rendered by distributing shadow rays over the light source area. Glossy or blurry re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
High-dynamic-range Imaging
In photography and videography, multi-exposure HDR capture is a technique that creates extended or high dynamic range (HDR) images by taking and combining multiple exposures of the same subject matter at different exposure levels. Combining multiple images in this way results in an image with a greater dynamic range than what would be possible by taking one single image. The technique can also be used to capture video by taking and combining multiple exposures for each frame of the video. The term "HDR" is used frequently to refer to the process of creating HDR images from multiple exposures. Many smartphones have an automated HDR feature that relies on computational imaging techniques to capture and combine multiple exposures. A single image captured by a camera provides a finite range of luminosity inherent to the medium, whether it is a digital sensor or film. Outside this range, tonal information is lost and no features are visible; tones that exceed the range are "burned o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 into computer graphics by David Immel et al. and James Kajiya in 1986. The various realistic rendering techniques in computer graphics attempt to solve this equation. The physical basis for the rendering equation is the law of conservation of energy. Assuming that ''L'' denotes radiance, we have that at each particular position and direction, the outgoing light (Lo) is the sum of the emitted light (Le) and the reflected light. The reflected light itself is the sum from all directions of the incoming light (Li) multiplied by the surface reflection and cosine of the incident angle. Equation form The rendering equation may be written in the form :L_(\mathbf x, \omega_, \lambda, t) = L_(\mathbf x, \omega_, \lambda, t) \ + \int_\Omega f_( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Show How 3D Real Time Ambient Occlusion Works 2013-11-23 10-45
Show or The Show may refer to: Competition, event, or artistic production * Agricultural show, associated with agriculture and animal husbandry * Animal show, a judged event in the hobby of animal fancy ** Cat show ** Dog show ** Horse show ** Specialty show, a dog show which reviews a single breed *Show, an artistic production, such as: ** Concert ** Radio show ** Talk show ** Television show ** Theatre production * Trade fair or trade show Arts, entertainment, and media Films * ''The Show'' (1922 film), starring Oliver Hardy * ''The Show'' (1927 film), directed by Tod Browning * ''The Show'' (1995 film), a hip hop documentary * ''The Show'' (2017 film), an American satirical drama * ''The Show'' (2020 film), a British mystery film Album * ''Show'' (The Cure album), 1993 * ''Show'' (The Jesus Lizard album), 1994 * ''The Show'' (album), a 2008 album by eMC Songs * "The Show" (Doug E. Fresh song) * "The Show" (Girls Aloud song) * "The Show" (Lenka song) * "The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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