The Free On-line Dictionary of Computing (30 December 2018):

ray tracing

    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.


(http://directory.google.com/Top/Computers/Software/Graphics/3D/Ray_Tracing/).

   (2003-09-11)