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Light Transport Theory
Light transport theory deals with the mathematics behind calculating the energy transfers between media that affect visibility. This article is currently specific to light transport in rendering processes such as global illumination and high dynamic range imaging (HDRI). Light Light Transport The amount of light transported is measured by flux density, or luminous flux per unit area on the point of the surface at which it is measured. Radiometry and Energy Transfer Radiometry is the science of measuring electromagnetic radiation, including visible light. It forms the foundation of light transport theory, which models how light interacts with surfaces, volumes, and media. * Energy Transfer Models: Light interacts with media through absorption, reflection, and transmission. These processes are governed by the rendering equation, which models the distribution of light in a scene. Geometric Models Hemisphere Given a surface S, a hemisphere H can be projected onto S to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rendering (computer Graphics)
Rendering is the process of generating a physically-based rendering, photorealistic or Non-photorealistic rendering, non-photorealistic image from input data such as 3D models. The word "rendering" (in one of its senses) originally meant the task performed by an artist when depicting a real or imaginary thing (the finished artwork is also called a "architectural rendering, rendering"). Today, to "render" commonly means to generate an image or video from a precise description (often created by an artist) using a computer program. A application software, software application or component-based software engineering, component that performs rendering is called a rendering software engine, engine, render engine, : Rendering systems, rendering system, graphics engine, or simply a renderer. A distinction is made between Real-time computer graphics, real-time rendering, in which images are generated and displayed immediately (ideally fast enough to give the impression of motion or an ... [...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] |
Ray Tracing (physics)
In physics, ray tracing is a method for calculating the path of waves or Subatomic particle, particles through a system with regions of varying propagation velocity, absorption characteristics, and reflecting surfaces. Under these circumstances, wavefronts may bend, change direction, or reflection (physics), reflect off surfaces, complicating analysis. Historically, ray tracing involved analytic solutions to the ray's trajectories. In modern applied physics and engineering physics, the term also encompasses numerical solutions to the Eikonal equation. For example, Ray marching, ray-marching involves repeatedly advancing idealized narrow beams called ''ray (optics), rays'' through the medium (optics), medium by discrete amounts. Simple problems can be analyzed by propagating a few rays using simple mathematics. More detailed analysis can be performed by using a computer to propagate many rays. When applied to problems of electromagnetic radiation, ray tracing often relies on appr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ray Tracing (graphics)
In 3D computer graphics, ray tracing is a technique for modeling Light transport theory, light transport for use in a wide variety of Rendering (computer graphics), rendering algorithms for generating digital image, digital images. On a spectrum of Computation time, computational cost and visual fidelity, ray tracing-based rendering techniques, such as ray casting, #Recursive ray tracing algorithm, recursive ray tracing, Distributed 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 still computer-generated imagery, CGI images, and film and television visual effects (VFX), but was less suited to real-time computer graphics, real-time applications such as video games, where Frame rate, speed is critical in rendering each Film frame, frame. Since 2018, however, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radiosity (computer Graphics)
In 3D computer graphics, radiosity is an application of the finite element method to solving the rendering equation for scenes with surfaces that reflect light diffusely. Unlike rendering methods that use Monte Carlo algorithms (such as path tracing), which handle all types of light paths, typical radiosity only account for paths (represented by the code "LD*E") which leave a light source and are reflected diffusely some number of times (possibly zero) before hitting the eye. Radiosity is a global illumination algorithm in the sense that the illumination arriving on a surface comes not just directly from the light sources, but also from other surfaces reflecting light. Radiosity is viewpoint independent, which increases the calculations involved, but makes them useful for all viewpoints. Radiosity methods were first developed in about 1950 in the engineering field of heat transfer. They were later refined specifically for the problem of rendering computer graphics in 19 ... [...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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monte Carlo Method
Monte Carlo methods, or Monte Carlo experiments, are a broad class of computational algorithms that rely on repeated random sampling to obtain numerical results. The underlying concept is to use randomness to solve problems that might be deterministic in principle. The name comes from the Monte Carlo Casino in Monaco, where the primary developer of the method, mathematician Stanisław Ulam, was inspired by his uncle's gambling habits. Monte Carlo methods are mainly used in three distinct problem classes: optimization, numerical integration, and generating draws from a probability distribution. They can also be used to model phenomena with significant uncertainty in inputs, such as calculating the risk of a nuclear power plant failure. Monte Carlo methods are often implemented using computer simulations, and they can provide approximate solutions to problems that are otherwise intractable or too complex to analyze mathematically. Monte Carlo methods are widely used in va ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 Lighting or illumination is the deliberate use of light to achieve practical or aesthetic effects. Lighting includes the use of both artificial light sources like lamps and light fixtures, as well as natural illumination by capturing daylight. ... 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 simulati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Path Tracing
Path tracing is a rendering algorithm in computer graphics that Simulation, simulates how light interacts with Physical object, objects, voxels, and Volumetric_path_tracing, participating media to generate realistic (''physically plausible'') Raster graphics, images. This Ray_tracing_(graphics), ray tracing technique uses the Monte Carlo method to accurately model global illumination, simulate different surface characteristics, and capture a wide range of effects observable in a camera system, such as optical properties of lenses (e.g., depth of field and bokeh) or the impact of Shutter (photography), shutter speed (e.g., motion blur and Exposure_value, exposure). By incorporating Physically_based_rendering, physically accurate materials and Light_transport_theory, light transport models, it can produce Photorealism, photorealistic results but requires significant computational power. Performance is often constrained by Video random-access memory, VRAM/Random-access memory, RAM ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photorealistic Rendering
__NOTOC__ In computer graphics, unbiased rendering or photorealistic rendering are Rendering (computer graphics), rendering techniques that avoid systematic errors, or Bias (statistics), statistical bias, in computing an image’s radiance. Bias in this context means inaccuracies like dimmer light or missing effects such as soft shadows, caused by approximations. Unbiased methods, such as path tracing and its derivatives, simulate real-world lighting and shading with full physical accuracy. In contrast, biased methods, including traditional Ray tracing (graphics), ray tracing, sacrifice precision for speed by using approximations that introduce errors—often seen as blur. This blur reduces variance (random noise) by averaging light samples, enabling faster computation with fewer samples needed for a clean image. Mathematical definition In mathematical terms, an unbiased estimator's expected value (E) is the population mean, regardless of the number of observations. The Error, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Soft Shadows
The umbra, penumbra and antumbra are three distinct parts of a shadow, created by any light source after impinging on an opaque object of lesser size. In cases of equal or smaller impinging objects, only an umbra and penumba are generated. Assuming no diffraction Diffraction is the deviation of waves from straight-line propagation without any change in their energy due to an obstacle or through an aperture. The diffracting object or aperture effectively becomes a secondary source of the Wave propagation ..., for a collimated beam (such as a point source) of light, only the umbra is cast. These phenomena are generally observed within solar systems, as the size of the stars within the system are larger than the orbiting satellites, hence these terms are most often used for the shadows cast by celestial body, celestial bodies, though they are sometimes used to describe levels of darkness, such as in sunspots. Umbra The umbra () is the innermost and darkest part of a shado ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Color Bleeding (computer Graphics)
In computer graphics and 3D rendering, color bleeding is the phenomenon in which objects or surfaces are colored by reflection of colored light from nearby surfaces. This is a visible effect that appears when a scene is rendered with Radiosity or full global illumination, or can otherwise be simulated by adding colored lights to a 3D scene. References * University of DüsseldorfGlossary of terms See also * Attribute clash Attribute clash (also known as colour clash or bleeding) is a display Visual artifact, artifact caused by limits in the graphics circuitry of some colour 8-bit home computers, most notably the ZX Spectrum, where it meant that only two colours ... * Radiosity 3D rendering {{compu-graphics-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
