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Newell's Algorithm
Newell's Algorithm is a 3D computer graphics procedure for elimination of polygon cycles in the depth sorting required in hidden surface removal. It was proposed in 1972 by brothers Martin Newell and Dick Newell, and Tom Sancha, while all three were working at CADCentre. In the depth sorting phase of hidden surface removal, if two polygons have no overlapping extents or extreme minimum and maximum values in the x, y, and z directions, then they can be easily sorted. If two polygons, and , do have overlapping extents in the Z direction, then it is possible that cutting is necessary. In that case Newell's algorithm tests the following: # Test for Z overlap; implied in the selection of the face from the sort list # The extreme coordinate values in X of the two faces do not overlap (minimax test in X) # The extreme coordinate values in Y of the two faces do not overlap (minimax test in Y) # All vertices of P lie deeper than the plane of # All vertices of Q lie closer to the viewp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
3D Computer Graphics
3D computer graphics, or “3D graphics,” sometimes called CGI, 3D-CGI or three-dimensional computer graphics are graphics that use a three-dimensional representation of geometric data (often Cartesian) that is stored in the computer for the purposes of performing calculations and rendering digital images, usually 2D images but sometimes 3D images. The resulting images may be stored for viewing later (possibly as an animation) or displayed in real time. 3D computer graphics, contrary to what the name suggests, are most often displayed on two-dimensional displays. Unlike 3D film and similar techniques, the result is two-dimensional, without visual depth. More often, 3D graphics are being displayed on 3D displays, like in virtual reality systems. 3D graphics stand in contrast to 2D computer graphics which typically use completely different methods and formats for creation and rendering. 3D computer graphics rely on many of the same algorithms as 2D computer vector gr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polygon
In geometry, a polygon () is a plane figure that is described by a finite number of straight line segments connected to form a closed ''polygonal chain'' (or ''polygonal circuit''). The bounded plane region, the bounding circuit, or the two together, may be called a polygon. The segments of a polygonal circuit are called its '' edges'' or ''sides''. The points where two edges meet are the polygon's '' vertices'' (singular: vertex) or ''corners''. The interior of a solid polygon is sometimes called its ''body''. An ''n''-gon is a polygon with ''n'' sides; for example, a triangle is a 3-gon. A simple polygon is one which does not intersect itself. Mathematicians are often concerned only with the bounding polygonal chains of simple polygons and they often define a polygon accordingly. A polygonal boundary may be allowed to cross over itself, creating star polygons and other self-intersecting polygons. A polygon is a 2-dimensional example of the more general polytope in any number ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hidden Surface Determination
In 3D computer graphics, hidden-surface determination (also known as shown-surface determination, hidden-surface removal (HSR), occlusion culling (OC) or visible-surface determination (VSD)) is the process of identifying what surfaces and parts of surfaces can be seen from a particular viewing angle. A hidden-surface determination algorithm is a solution to the visibility problem, which was one of the first major problems in the field of 3D computer graphics . The process of hidden-surface determination is sometimes called hiding, and such an algorithm is sometimes called a hider. When referring to line rendering it is known as hidden-line removal. Hidden-surface determination is necessary to render a scene correctly, so that one may not view features hidden behind the model itself, allowing only the naturally viewable portion of the graphic to be visible. Background Hidden-surface determination is a process by which surfaces that should not be visible to the user (for example, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Martin Newell (computer Scientist)
Martin Edward Newell is a British-born computer scientist specializing in computer graphics who is perhaps best known as the creator of the Utah teapot computer model. Career Before emigrating to the US, he worked at what was then the Computer-Aided Design Centre ( CADCentre) in Cambridge, UK, along with his brother Dick Newell (who went on to co-found two of the most important UK graphics software companies – Cambridge Interactive Systems (CIS) in 1977 and Smallworld in 1987). At CADCentre, the two Newells and Tom Sancha developed Newell's algorithm, a technique for eliminating cyclic dependencies when ordering polygons to be drawn by a computer graphics system. Newell developed the Utah teapot while working on a Ph.D. at the University of Utah, where he also helped develop a version of the painter's algorithm for rendering. He graduated in 1975, and was on the Utah faculty from 1977 to 1979. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dick Newell
Richard G. Newell is a British businessman and technologist in the software industry in Computer aided design (CAD) and Geographic Information Systems (GIS). Career Newell holds degrees in Civil Engineering and Numerical Analysis and a PhD in Chemical Engineering from Imperial College, London. As a software engineer, he worked at CADCentre alongside his brother Martin Newell who is perhaps best known as the creator of the Utah Teapot (or Newell teapot). It was at the centre that Newell oversaw the creation of the successful Plant Design Management System (PDMS) for 3D process plant design. In 1972 Newell, his brother Martin and Tom Sancha proposed the Newell's algorithm procedure. He co-founded his first company, Cambridge Interactive Systems Ltd. (CIS) in 1977. CIS was part of what became known as 'The Cambridge Phenomenon'. by David Connell and Jocelyn Probert Centre for Business Research, University of Cambridge Newell co-founded Smallworld Systems in 1988. The company was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Painters Problem
Painting is the practice of applying paint, pigment, color or other medium to a solid surface (called the "matrix" or "support"). The medium is commonly applied to the base with a brush, but other implements, such as knives, sponges, and airbrushes, can be used. In art, the term ''painting ''describes both the act and the result of the action (the final work is called "a painting"). The support for paintings includes such surfaces as walls, paper, canvas, wood, glass, lacquer, pottery, leaf, copper and concrete, and the painting may incorporate multiple other materials, including sand, clay, paper, plaster, gold leaf, and even whole objects. Painting is an important form in the visual arts, bringing in elements such as drawing, composition, gesture (as in gestural painting), narration (as in narrative art), and abstraction (as in abstract art). Paintings can be naturalistic and representational (as in still life and landscape painting), photographic, abstract, narrative, sy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Minimax
Minimax (sometimes MinMax, MM or saddle point) is a decision rule used in artificial intelligence, decision theory, game theory, statistics, and philosophy for ''mini''mizing the possible loss for a worst case (''max''imum loss) scenario. When dealing with gains, it is referred to as "maximin" – to maximize the minimum gain. Originally formulated for several-player zero-sum game theory, covering both the cases where players take alternate moves and those where they make simultaneous moves, it has also been extended to more complex games and to general decision-making in the presence of uncertainty. Game theory In general games The maximin value is the highest value that the player can be sure to get without knowing the actions of the other players; equivalently, it is the lowest value the other players can force the player to receive when they know the player's action. Its formal definition is: :\underline = \max_ \min_ Where: * is the index of the player of interest. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rasterisation
In computer graphics, rasterisation (British English) or rasterization (American English) is the task of taking an image described in a vector graphics format (shapes) and converting it into a raster image (a series of pixels, dots or lines, which, when displayed together, create the image which was represented via shapes). The rasterized image may then be displayed on a computer display, video display or printer, or stored in a bitmap file format. Rasterization may refer to the technique of drawing 3D models, or the conversion of 2D rendering primitives such as polygons, line segments into a rasterized format. Etymology The term "rasterisation" comes . 2D Images Line primitives Bresenham's line algorithm is an example of algorithm used to render a line. Circle primitives Algorithms such as Midpoint circle algorithm are used to render circle onto a pixelated canvas. 3D images Rasterization is one of the typical techniques of rendering 3D models. Compared with other re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plane (geometry)
In mathematics, a plane is a Euclidean (flat), two-dimensional surface that extends indefinitely. A plane is the two-dimensional analogue of a point (zero dimensions), a line (one dimension) and three-dimensional space. Planes can arise as subspaces of some higher-dimensional space, as with one of a room's walls, infinitely extended, or they may enjoy an independent existence in their own right, as in the setting of two-dimensional Euclidean geometry. Sometimes the word ''plane'' is used more generally to describe a two-dimensional surface, for example the hyperbolic plane and elliptic plane. When working exclusively in two-dimensional Euclidean space, the definite article is used, so ''the'' plane refers to the whole space. Many fundamental tasks in mathematics, geometry, trigonometry, graph theory, and graphing are performed in a two-dimensional space, often in the plane. Euclidean geometry Euclid set forth the first great landmark of mathematical thought, an axiomatic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Painter's Algorithm
The painter’s algorithm (also depth-sort algorithm and priority fill) is an algorithm for visible surface determination in 3D computer graphics that works on a polygon-by-polygon basis rather than a pixel-by-pixel, row by row, or area by area basis of other Hidden Surface Removal algorithms. The painter’s algorithm creates images by sorting the polygons within the image by their depth and placing each polygon in order from the farthest to the closest object. The painter's algorithm was initially proposed as a basic method to address the Hidden-surface determination problem by Martin Newell, Richard Newell, and Tom Sancha in 1972, while all three were working at CADCentre. The name "painter's algorithm" refers to the technique employed by many painters where they begin by painting distant parts of a scene before parts that are nearer, thereby covering some areas of distant parts. Similarly, the painter's algorithm sorts all the polygons in a scene by their depth and then p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boolean Operations On Polygons
Boolean operations on polygons are a set of Boolean operations (AND, OR, NOT, XOR, ...) operating on one or more sets of polygons in computer graphics. These sets of operations are widely used in computer graphics, CAD, and in EDA (in integrated circuit physical design and verification software). Algorithms * Greiner–Hormann clipping algorithm * Vatti clipping algorithm * Sutherland–Hodgman algorithm (special case algorithm) * Weiler–Atherton clipping algorithm (special case algorithm) Uses in software Early algorithms for Boolean operations on polygons were based on the use of bitmaps. Using bitmaps in modeling polygon shapes has many drawbacks. One of the drawbacks is that the memory usage can be very large, since the resolution of polygons is proportional to the number of bits used to represent polygons. The higher the resolution is desired, the more the number of bits is required. Modern implementations for Boolean operations on polygons tend to use plane sweep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
