Actually, these two situations solve similar but different parts of the
global illumination problem.  Photons in POV only solve light transport from
light_source objects to the first diffuse surface.  POV's photons stop when
they hit a diffuse surface.  POV's radiosity, on the other hand, tracks
light transport from diffuse (or ambient) surfaces to other diffuse
surfaces.  Along the way, the light might be reflected or refracted.
Basically, POV's radiosity picks up where photons and direct lighting stop.

Because of this, using photons and HRDI together with the suggested method
(save_file and load_file) will provide an inaccurate (though probably
good-looking) render, because you would be using both photons and radiosity
to solve the same part of the light transport model.

-Nathan


"George Pantazopoulos" <the### [at] attbicom*KILLSPAM*> wrote...
>     This is where I disagree with POV-Ray's radiosity implementation.
> Radiosity is for simulating diffuse interreflection. Simulating specular
> interactions during the process of shooting radiosity rays is a waste and
is
> better done using POV-Ray's excellent photon mapping. Fortunately this was
> easy to fix. I did it in my own personal patch, and it has resulted in
some
> nice speedups when doing two-pass renders (in scenes that contain
> reflections etc). :)
>
> George
>
> > But actually these images were just a test to see if radiosity takes
> reflection
> > and ior into account, which it does :)
> >
>
>
>

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