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From: cloister@milton.u.washington.edu (cloister bell)
Newsgroups: alt.fractals,sci.math,comp.graphics
Subject: Re: 3-d fractal raytracer?
Message-ID: <1991May3.190846.22736@milton.u.washington.edu>
Date: 3 May 91 19:08:46 GMT
References: <1991Apr30.074427.29894@milton.u.washington.edu> <1991May3.085302.18527@zorch.SF-Bay.ORG> <1991May3.183504.12985@milton.u.washington.edu>
Organization: University of Washington
Lines: 25

bungi@milton.u.washington.edu (Timothy J. Wood) writes:

>In article <1991May3.085302.18527@zorch.SF-Bay.ORG> xanthian@zorch.SF-Bay.ORG (Kent Paul Dolan) writes:
>>
>>Does one limit resolution, do some local smoothing, and take the normal
>>to the resultant bounding surface?
>>

>  The method i'm using is an approximation based on the gradient of the
>distance estimator function d(z) presented in 'The Science of Fractal
>Images' (Peitgen).  One can also use the gradient of the potential function
>G(z) (from the same source).

which to me seems a valid method.  the whole idea behind ray tracing is to
simulate what happens to light rays when they hit things.  when a light ray
hits a fractal object (if there were such things in the real world) since the
scale of the features on the surface will be (because it's a fractal) smaller
than the wavelength of the photon that hits it.  recalling my physics classes
of several years ago, when this sort of things happens, the photon is going to
bounce in ways related to the average (i.e. 'macroscopic' in whatever sense
that word applies to photons) gradient of the surface.  best of luck, mr. wood.
-- 
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|i thought of a good sig, but it was a sight gag. | cloister@u.washington.edu |
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