ray casting
<graphics>
A simplified form of ray tracing. A ray is fired from each pixel in the view plane, and information is accumulated from all the voxels in the volume data it intersects.
Each voxel is first given an associated colour and opacity. The ray is sampled at a fixed number of evenly spaced locations and the colour and opacity are trilinearly interpolated from the eight nearest voxels. These are then composed linearly back to front to give a single colour for the pixel. Ray casting was invented by John Carmack for the game Wolfenstein 3D. It is faster and lower quality than ray tracing, and is ideal for interactive applications. It parallelises well, although random access is needed to the voxels.Last updated: 2004-01-06
Rayleigh distribution
A curve that yields a good approximation to the actual labour curves on software projects.
[Details? Equation?]Last updated: 1996-05-29
Ray Tomlinson
<person>
An engineer at Bolt Beranek and Newman who, in July 1972 while designing the first[?] electronic mail program, chose the commercial at symbol "@" to separate the user name from the computer name.
Last updated: 2004-08-22
ray tracing
<graphics>
A technique used in computer graphics to create realistic images by calculating the paths taken by rays of light entering the observer's eye at different angles. The paths are traced backward from the viewpoint, through a point (a pixel) in the image plane until they hit some object in the scene or go off to infinity. Objects are modelled as collections of abutting surfaces which may be rectangles, triangles, or more complicated shapes such as 3D splines. The optical properties of different surfaces (colour, reflectance, transmitance, refraction, texture) also affect how it will contribute to the colour and brightness of the ray. The position, colour, and brightness of light sources, including ambient lighting, is also taken into account.
Ray tracing is an ideal application for parallel processing since there are many pixels, each of whose values is independent and can thus be calculated in parallel. Compare: radiosity. Usenet newsgroup: comp.graphics.raytracing. http://directory.google.com/Top/Computers/Software/Graphics/3D/Ray_Tracing/.Last updated: 2003-09-11
Nearby terms:
RAWOOP-SNAP ♦ ray casting ♦ Rayleigh distribution ♦ Ray Tomlinson
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