Slime <fak### [at] emailaddress> wrote:
> Well, in POV-Ray, light is modeled in a mathematically correct way to
> simulate reality.

  Technically that's hardly true.

  Point lights do not exist in reality (a point light is infinitely
small - a mathematical point - and such light sources do not exist).
A point light in POV-Ray is an approximation of a small and distant light
source, not a mathematically correct exact simulation.

  In real life all light sources are area ligths of one shape or another.
However, POV-Ray fails to simulate this in a mathematically exact way
as well (the reason being simply that it would be way too heavy, if not
impossible to do so). POV-Ray only approximates area lights in a way that
looks good enough in the final image.

  In real life also all surfaces emit light as well (by reflecting light)
and thus act as light sources. While POV-Ray can approximate this with a
stochastic algorithm, that's also just an (often quite inaccurate)
approximation.

  What you meant was that POV-Ray creates shadows by simulating real-life
light sources and does not "create shadows" which exist on their own
independent of any light source (like most scanline renderers do). Thus
the look of shadows are always defined by the light source causing these
shadows, and a shadow itself is not any primitive or entity you could
handle in POV-Ray.

-- 
#macro M(A,N,D,L)plane{-z,-9pigment{mandel L*9translate N color_map{[0rgb x]
[1rgb 9]}scale<D,D*3D>*1e3}rotate y*A*8}#end M(-3<1.206434.28623>70,7)M(
-1<.7438.1795>1,20)M(1<.77595.13699>30,20)M(3<.75923.07145>80,99)// - Warp -

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