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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] |
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] |
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] |
Beam Tracing
Beam tracing is an algorithm to simulate wave propagation. It was developed in the context of computer graphics to render 3D scenes, but it has been also used in other similar areas such as acoustics and electromagnetism simulations. Beam tracing is a derivative of the ray tracing algorithm that replaces rays, which have no thickness, with beams. Beams are shaped like unbounded pyramids, with (possibly complex) polygonal cross sections. Beam tracing was first proposed by Paul Heckbert and Pat Hanrahan. In beam tracing, a pyramidal beam is initially cast through the entire viewing frustum. This initial viewing beam is intersected with each polygon in the environment, typically from nearest to farthest. Each polygon that intersects with the beam must be visible, and is removed from the shape of the beam and added to a render queue. When a beam intersects with a reflective or refractive polygon, a new beam is created in a similar fashion to ray-tracing. A variant of beam traci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Portal Rendering
In computer-generated imagery and real-time 3D computer graphics, portal rendering is an algorithm for visibility determination. For example, consider a 3D computer game environment, which may contain many polygons, only a few of which may be visible on screen at a given time. By determining which polygons are currently not visible, and not rendering those objects, significant performance improvements can be achieved. A portal system is based on using the partitioning of space to form generalizations about the visibility of objects within those spaces. Regions of map space are divided into polygonal, generally convex, areas called ''zones'', or sometimes ''sectors''. Adjacent zones are linked to one another via shared dividing polygons termed ''portals''. Approaches that precompute visibility for zones are referred to as potentially visible set or ''PVS'' methods. For example, in a computer game such as ''Descent'', the game area might be divided into several zones. These zon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potentially Visible Set
In 3D computer graphics, Potentially Visible Sets are used to accelerate the rendering of 3D environments. They are a form of occlusion culling, whereby a candidate set of ''potentially visible'' polygons are pre-computed, then indexed at run-time in order to quickly obtain an estimate of the visible geometry. The term ''PVS'' is sometimes used to refer to any occlusion culling algorithm (since in effect, this is what all occlusion algorithms compute), although in almost all the literature, it is used to refer specifically to occlusion culling algorithms that pre-compute visible sets and associate these sets with regions in space. In order to make this association, the camera's view-space (the set of points from which the camera can render an image) is typically subdivided into (usually convex) regions and a PVS is computed for each region. Benefits vs. Cost The benefit of offloading visibility as a pre-process are: * The application just has to look up the pre-computed se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Depth Complexity
Depth(s) may refer to: Science and mathematics * Three-dimensional space * Depth (ring theory), an important invariant of rings and modules in commutative and homological algebra * Depth in a well, the measurement between two points in an oil well * Color depth (or "number of bits" or "bit depth"), in computer graphics * Market depth, in financial markets, the size of an order needed to move the market a given amount * Moulded depth, a nautical measurement * Sequence depth, or coverage, in genetic sequencing * Depth (coordinate), a type of vertical distance * Tree depth Art and entertainment * ''Depth'' (video game), an Indie video game * ''Depths'' (novel), a 2004 novel by Henning Mankell * ''Depths'' (Oceano album), 2009 * ''Depths'' (Windy & Carl album), 1998 * "Depths" (''Law & Order: Criminal Intent''), an episode of ''Law & Order: Criminal Intent'' * ''Depth'', the Japanese title for the PlayStation game released in Europe under the name ''Fluid'' * Depth, an as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clipping Plane
A clipping path (or "deep etch") is a closed vector path, or shape, used to cut out a 2D image in image editing software. Anything inside the path will be included after the clipping path is applied; anything outside the path will be omitted from the output. Applying the clipping path results in a hard (aliased) or soft (anti-aliased) edge, depending on the image editor's capabilities By convention, the inside of the path is defined by its direction. Reversing the direction of a path reverses what is considered inside or outside. An ''inclusive path'' is one where what is visually "inside" the path corresponds to what will be preserved; an ''exclusive path'', of opposite direction, contains what is visually "outside" the path. By convention, a clockwise path that is non-self-intersecting is considered inclusive. A compound path results from the combination of multiple paths (inclusive and exclusive) and the Boolean operations that ultimately determine what the combined path con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
3D Projection
A 3D projection (or graphical projection) is a design technique used to display a three-dimensional (3D) object on a two-dimensional (2D) surface. These projections rely on visual perspective and aspect analysis to project a complex object for viewing capability on a simpler plane. 3D projections use the primary qualities of an object's basic shape to create a map of points, that are then connected to one another to create a visual element. The result is a graphic that contains conceptual properties to interpret that the figure or image as not actually flat (2D), but rather, as a solid object (3D) being viewed on a 2D display. 3D objects are largely displayed on two-dimensional mediums (i.e. paper and computer monitors). As such, graphical projections are a commonly used design element; notably, in engineering drawing, drafting, and computer graphics. Projections can be calculated through employment of mathematical analysis and formulae, or by using various geometric and o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virtual Camera
In 3D video games, a virtual camera system aims at controlling a camera or a set of cameras to display a view of a 3D virtual world. Camera systems are used in video games where their purpose is to show the action at the best possible angle; more generally, they are used in 3D virtual worlds when a third-person view is required. As opposed to filmmakers, virtual camera system creators have to deal with a world that is interactive and unpredictable. It is not possible to know where the player character is going to be in the next few seconds; therefore, it is not possible to plan the shots as a film maker would do. To solve this issue, the system relies on certain rules or artificial intelligence to select the most appropriate shots. There are mainly three types of camera systems. In ''fixed camera systems'', the camera does not move at all and the system displays the player's character in a succession of still shots. ''Tracking cameras'', on the other hand, follow the characte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Viewing Frustum
In 3D computer graphics, the view frustum (also called viewing frustum) is the region of space in the modeled world that may appear on the screen; it is the field of view of a perspective virtual camera system. The view frustum is typically obtained by taking a frustum—that is a truncation with parallel planes—of the pyramid of vision, which is the adaptation of (idealized) cone of vision that a camera or eye would have to the rectangular viewports typically used in computer graphics. Some authors use ''pyramid of vision'' as a synonym for view frustum itself, i.e. consider it truncated. The exact shape of this region varies depending on what kind of camera lens is being simulated, but typically it is a frustum of a rectangular pyramid (hence the name). The planes that cut the frustum perpendicular to the viewing direction are called the ''near plane'' and the ''far plane''. Objects closer to the camera than the near plane or beyond the far plane are not drawn. Sometimes, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Warnock Algorithm
The Warnock algorithm is a hidden surface algorithm invented by John Warnock that is typically used in the field of computer graphics. It solves the problem of rendering a complicated image by recursive subdivision of a scene until areas are obtained that are trivial to compute. In other words, if the scene is simple enough to compute efficiently then it is rendered; otherwise it is divided into smaller parts which are likewise tested for simplicity., 608 pages This is a divide and conquer algorithm In computer science, divide and conquer is an algorithm design paradigm. A divide-and-conquer algorithm recursively breaks down a problem into two or more sub-problems of the same or related type, until these become simple enough to be solved dire ... with run-time of O(np), where ''n'' is the number of polygons and ''p'' is the number of pixels in the viewport. The inputs are a list of polygons and a viewport. The best case is that if the list of polygons is simple, then draw the ... [...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] |
