"clipka" <nomail@nomail> wrote:
>
> > http://tag.povray.org/povQandT/languageQandT.html#blurredreflection
>
> [Read that] already a while ago.
>
> The averaged textures approach didn't stick though. Maybe because it's *fatal*
> if you have a lot of reflecting surfaces: The rays POV needs to trace will
> explode exponentially with each reflection.

That was exactly the problem I found.

> In contrast, if you do the averaging via multiple renders + post-processing, the
> number of rays is only increased by a constant factor; at each reflection, the
> number of rays multiplies only by the same amount as if the scene used sharp
> reflections.

And that's the same answer I came up with, and I also use the multiple passes to
do anti-aliasing, focal blur, soft shadows, lightdome IBL lighting and I'm just
starting to try putting media in there too. And the render time stays almost
constant with each new effect, as the "quality" for each comes from the
multiple renders you are already committed to.

> After the first blurred reflection, there's actually not much benefit in
> multiplying the number of rays even more.

If the POV team wants to keep the current way of allowing blurred reflection,
then I would suggest having some sort of reflection control to say how many
rays are propagated at each reflection. That way you could have 100 rays at the
first object, but only the first 10 of those reflect themselves. Sort of a
max_trace that varies based on whether the ray is reflection 1, 10 or 100.

Cheers,
Edouard.

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