Daylight Factor
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Daylight Factor
In architecture, a daylight factor (DF) is the ratio of the light level inside a structure to the light level outside the structure. It is defined as: :''DF = (Ei / Eo) x 100%'' where, ''Ei'' = illuminance due to daylight at a point on the indoors working plane, ''Eo'' = simultaneous outdoor illuminance on a horizontal plane from an unobstructed hemisphere of overcast sky. To calculate ''Ei'', requires knowing the amount of outside light received inside of a building. Light can reach a room via through a glazed window, rooflight, or other aperture via three paths: * Direct light from a patch of sky visible at the point considered, known as the sky component (''SC''), * Light reflected from an exterior surface and then reaching the point considered, known as the externally reflected component (''ERC''), * Light entering through the window but reaching the point only after reflection from an internal surface, known as the internally reflected component (''IRC''). The sum of the thr ...
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Architecture
Architecture is the art and technique of designing and building, as distinguished from the skills associated with construction. It is both the process and the product of sketching, conceiving, planning, designing, and constructing buildings or other structures. The term comes ; ; . Architectural works, in the material form of buildings, are often perceived as cultural symbols and as works of art. Historical civilizations are often identified with their surviving architectural achievements. The practice, which began in the prehistoric era, has been used as a way of expressing culture for civilizations on all seven continents. For this reason, architecture is considered to be a form of art. Texts on architecture have been written since ancient times. The earliest surviving text on architectural theories is the 1st century AD treatise '' De architectura'' by the Roman architect Vitruvius, according to whom a good building embodies , and (durability, utility, and beauty). ...
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Daylight
Daylight is the combination of all direct and indirect sunlight during the daytime. This includes direct sunlight, diffuse sky radiation, and (often) both of these reflected by Earth and terrestrial objects, like landforms and buildings. Sunlight scattered or reflected by astronomical objects is generally not considered daylight. Therefore, daylight excludes moonlight, despite it being reflected indirect sunlight. Definition Daylight is present at a particular location, to some degree, whenever the Sun is above the local horizon. (This is true for slightly more than 50% of the Earth at any given time. For an explanation of why it is not exactly half, see here). However, the outdoor illuminance can vary from 120,000 lux for direct sunlight at noon, which may cause eye pain, to less than 5 lux for thick storm clouds with the Sun at the horizon (even <1 lux for the most extreme case), which may make shadows from distant
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Daylight Factor Study Colour Plot
Daylight is the combination of all direct and indirect sunlight during the daytime. This includes direct sunlight, diffuse sky radiation, and (often) both of these reflected by Earth and terrestrial objects, like landforms and buildings. Sunlight scattered or reflected by astronomical objects is generally not considered daylight. Therefore, daylight excludes moonlight, despite it being reflected indirect sunlight. Definition Daylight is present at a particular location, to some degree, whenever the Sun is above the local horizon. (This is true for slightly more than 50% of the Earth at any given time. For an explanation of why it is not exactly half, see here). However, the outdoor illuminance can vary from 120,000 lux for direct sunlight at noon, which may cause eye pain, to less than 5 lux for thick storm clouds with the Sun at the horizon (even <1 lux for the most extreme case), which may make shadows from distant

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International Commission On Illumination
The International Commission on Illumination (usually abbreviated CIE for its French name, Commission internationale de l'éclairage) is the international authority on light, illumination, colour, and colour spaces. It was established in 1913 as a successor to the Commission Internationale de Photométrie, which was founded in 1900, and is today based in Vienna, Austria. Organization The CIE has six active divisions, each of which establishes technical committees to carry out its program: * Division 1: Vision and Colour * Division 2: Physical Measurement of Light and Radiation * Division 3: Interior Environment and Lighting Design * Division 4: Transportation and Exterior Applications * Division 6: Photobiology and Photochemistry * Division 8: Image Technology Two divisions are no longer active: * Division 5: Exterior Lighting and Other Applications * Division 7: General Aspects of Lighting The President of the CIE from 2019 is Dr Peter Blattner from Switzerland. CIE publi ...
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Radiance (software)
Radiance is a suite of tools for performing '' lighting simulation'' originally written by Greg Ward. It includes a renderer as well as many other tools for measuring the simulated light levels. It uses ray tracing to perform all lighting calculations, accelerated by the use of an octree data structure. It pioneered the concept of high-dynamic-range imaging, where light levels are (theoretically) open-ended values instead of a decimal proportion of a maximum (e.g. 0.0 to 1.0) or integer fraction of a maximum (0 to 255 / 255). It also implements global illumination using the Monte Carlo method to sample light falling on a point. Greg Ward started developing Radiance in 1985 while at Lawrence Berkeley National Laboratory. The source code was distributed under a license forbidding further redistribution. In January 2002 Radiance 3.4 was relicensed under a less restrictive license. One study found Radiance to be the most generally useful software package for architectural lighting s ...
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Rendering (computer Graphics)
Rendering or image synthesis is the process of generating a photorealistic or non-photorealistic image from a 2D or 3D model by means of a computer program. The resulting image is referred to as the render. Multiple models can be defined in a ''scene file'' containing objects in a strictly defined language or data structure. The scene file contains geometry, viewpoint, texture, lighting, and shading information describing the virtual scene. The data contained in the scene file is then passed to a rendering program to be processed and output to a digital image or raster graphics image file. The term "rendering" is analogous to the concept of an artist's impression of a scene. The term "rendering" is also used to describe the process of calculating effects in a video editing program to produce the final video output. Rendering is one of the major sub-topics of 3D computer graphics, and in practice it is always connected to the others. It is the last major step in the gr ...
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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- ...
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Chartered Institution Of Building Services Engineers
The Chartered Institution of Building Services Engineers (CIBSE; pronounced 'sib-see') is an international professional engineering association based in London, England that represents building services engineers. It is a full member of the Construction Industry Council, and is consulted by government on matters relating to construction, engineering and sustainability. It is also licensed by the Engineering Council to assess candidates for inclusion on its Register of Professional Engineers. History CIBSE was formed in 1976 receiving a Royal Charter the same year, following a merger of the Institution of Heating and Ventilation Engineers (founded in 1897) and the Illuminating Engineering Society (founded in 1909). Previously CIBS, the word 'Engineers' was added in 1985, and hence the Institution became CIBSE. Royal Charter In accordance with the CIBSE Royal Charter and By-laws, the Institution's primary objects are: * The promotion for the benefit of the public in general of t ...
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Daylighting
Daylighting is the practice of placing windows, skylights, other openings, and Reflective surfaces (climate engineering), reflective surfaces so that sunlight (direct or indirect) can provide effective internal lighting. Particular attention is given to daylighting while designing a building when the aim is to maximize visual comfort or to reduce energy use. Energy savings can be achieved from the reduced use of artificial (electric) lighting or from passive solar heating. Artificial lighting energy use can be reduced by simply installing fewer electric lights where daylight is present or by automatically Dimmer, dimming/switching off electric lights in response to the presence of daylight – a process known as daylight harvesting. The amount of daylight received in an internal space can be analyzed by measuring illuminance on a grid or undertaking a daylight factor calculation. Computer programs such as Radiance (software), Radiance allow an architect or engineer to quickly cal ...
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Right To Light
Right to light is a form of easement in English law that gives a long-standing owner of a building with windows a right to maintain an adequate level of illumination. The right was traditionally known as the doctrine of "ancient lights". It is also possible for a right to light to exist if granted expressly by deed, or granted implicitly, for example under the rule in '' Wheeldon v. Burrows'' (1879). In England, the rights to ancient lights are most usually acquired under the Prescription Act 1832. In American common law the doctrine died out during the 19th century, and is generally no longer recognized in the United States. Japanese law provides for a comparable concept known as ''nisshōken'' (literally "right to sunshine"). Rights In effect, the owner of a building with windows that have received natural daylight for 20 years or more is entitled to forbid any construction or other obstruction on adjacent land that would block the light so as to deprive him or her of adeq ...
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Light
Light or visible light is electromagnetic radiation that can be perceived by the human eye. Visible light is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequencies of 750–420 terahertz, between the infrared (with longer wavelengths) and the ultraviolet (with shorter wavelengths). In physics, the term "light" may refer more broadly to electromagnetic radiation of any wavelength, whether visible or not. In this sense, gamma rays, X-rays, microwaves and radio waves are also light. The primary properties of light are intensity, propagation direction, frequency or wavelength spectrum and polarization. Its speed in a vacuum, 299 792 458 metres a second (m/s), is one of the fundamental constants of nature. Like all types of electromagnetic radiation, visible light propagates by massless elementary particles called photons that represents the quanta of electromagnetic field, and can be analyzed as both waves and par ...
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Visibility
The visibility is the measure of the distance at which an object or light can be clearly discerned. In meteorology it depends on the transparency of the surrounding air and as such, it is unchanging no matter the ambient light level or time of day. It is reported within surface weather observations and METAR code either in meters or statute miles, depending upon the country. Visibility affects all forms of traffic: roads, sailing and aviation. The geometric range of vision is limited by the curvature of the earth and depends on the eye level and the height of the object being viewed. In geodesy, the atmospheric refraction must be taken into account when calculating geodetic visibility. Meteorological visibility Definition ICAO Annex 3 ''Meteorological Service for International Air Navigation'' contains the following definitions and note: :a) the greatest distance at which a black object of suitable dimensions, situated near the ground, can be seen and recognized when o ...
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