"Mr" <nomail@nomail> wrote:
> AFAIK, Ambient Occlusion is used to gain some render time and flexibility
> rather than realism.

Exactly, it's fast and really brings out hidden geometric details that radiosity
doesn't typically reveal, and our brains are fooled into thinking it looks more
realistic even when it's not physically accurate.

> It is often said that AO is not phisically correct, but I'd say that for a
> uniformly and very thickly overcast sky with no lights around, then only AO
> would be correct. Or the light cast by surrounding sky of some clear night.

Yes, and my AO solution is really just that: white materials under a very
thickly overcast sky with no lights around.

> So when you consider that you actually don't use AO by itself but only to take
> care of some part of the light, you realize that this lighting component is to
> various degrees present in almost every scene.

I usually only multiply in 15-50% of the AO pass, depending on the shot.

> There are also other uses of AO like to bake it and use as a basis for dirt
> maps, mask to mix different materials and many textures to process further.

That's something else I'm working on, using the AO pass as an image_pattern mask
to control grime and such in crevices, for an additional dirt/grime pass.

> @Robert McGregor, Even If AO does not get implemented further into POV, I'm much
> interested into any tutorial you could make and would love to include pov passes
> to our Blender 2.5 to Povray exporter because Blender compositing pipeline is
> quite capable and that's an area where both software would best synergize.
> Thanks for your efforts.

Thanks, that sounds great; I'd be very interested to work with you on that!

Cheers,
Rob
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www.McGregorFineArt.com

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