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From: jet@karazm.math.uh.edu (J Eric Townsend)
Subject: Re: Radiosity
Message-ID: <1991Jun23.205937.7246@menudo.uh.edu>
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Organization: University of Houston -- Department of Mathematics
References: <1991Jun23.202448.22614@mintaka.lcs.mit.edu>
Date: Sun, 23 Jun 1991 20:59:37 GMT

In article <1991Jun23.202448.22614@mintaka.lcs.mit.edu> rjc@geech.gnu.ai.mit.edu (Ray Cromwell) writes:
>   Can't someone explain what this is, and what is the difference
>between this and normal ray-tracing. I know how ray-tracing and
>scanline rendering works, is this just another buzzword for ray-tracing?

Simply put, you describe a scene with "patches".  Each patch can either
emit or reflect energy (light).  Using some sort of linear algebra
or another, one sets up a set of linear equations and solves for
each "patch".  You know have the light value for each and every
patch in the scene.  Now, chuck the data into your favorite rendering
package and whammo, a picture!

That's the $.02 explination.  For more info, see the following papers
as a start:


%A James Arvo
%A David Kirk
%T Particle Transport and Image Synthesis
%J Computer Graphics (SIGGRAPH '90 Proceedings)
%V 24
%N 4
%D August 1990
%P 63-66
%K Boltzmann equation, Monte Carlo, particle transport, ray tracing, rendering
equation


%A Chris Buckalew
%A Donald Fussell
%T Illumination Networks: Fast Realistic Rendering with General Reflectance 
Functions
%J Computer Graphics (SIGGRAPH '89 Proceedings)
%V 23
%N 3
%D July 1989
%P 89-98


%A Michael Cohen
%A Donald P. Greenberg
%T The Hemi-Cube: A Radiosity Solution for Complex Environments
%J Computer Graphics (SIGGRAPH '85 Proceedings)
%V 19
%N 3
%D Aug. 1985
%P 31-40


And, since radiosity is in essence, the heat equation:
%A R.V. Dunkle
%T Radiant Interchange in an Enclosure with Specular Surfaces and Enclosures
with Window or Diathermanous Walls
%B Heat Transfer, Thermodynamics and Education (Boelter Anniversary Volume)
%E H.A. Johnson
%I McGraw Hill
%C New York
%D 1964

%A E.R.G. Eckert
%A E.M. Sparrow
%T Radiative Heat Exchange Between Surfaces with Specular Reflection
%J International Journal of Heat and Mass Transfer
%V 3
%D 1961
%P 42-54

%A R. Farrell
%T Determination of Configuration Factors of Irregular Shapes
%J Journal of Heat Transfer
%D May 1976
%P 311-313

--
J. Eric Townsend - jet@uh.edu - bitnet: jet@UHOU - vox: (713) 749-2126
Skate UNIX! (curb fault: skater dumped)

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