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: news:comp.graphics.raytracing.

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(2003-09-11)