clipka <ano### [at] anonymousorg> wrote:
> Am 11.03.2011 11:30, schrieb nemesis:
> > clipka<ano### [at] anonymousorg>  wrote:
> >> Am 09.03.2011 17:09, schrieb nemesis:
> >> The multipass approach
> >> has its limitations; for instance. AO breaks down for indoor scenes.
> >
> > Only because its not true AO, just radiosity under an overcast sky. ;)
>
> So what /is/ true AO? From the little I know it is an effect limited to
> a single object, to account for self-shadowing

I think you got that wrong.  It's not about self-shadowing, but about accounting
for geometry occluding light from close geometry, like a sphere on the floor
generating shadows on the floor and the floor generating shadows on the sphere.
It also doesn't take light setups into account at all, just how close geometry
is to each other.  That is, it's perfectly possible to have AO in-doors in a
closed room, under a ceiling which is not emitting light (as would be needed in
radiosity).  AFAIK, the calculations needed involve purely the normals between
surfaces, like the shadowing in the corners of rooms where 2 walls join and even
more when floor or ceiling join in as well...

> > It's used in a bunch of radiosity HOF scenes to handle reflections without using
> > exponentially increased rendertimes and more radiosity artifacts (at least for
> > older radiosity)...
>
> Yup, 3.6 radiosity was indeed prone to artifacts when reflections were
> involved, and those artifacts were virtually impossible to get rid of.
> No such problem in 3.7 anymore, and the new radiosity importance
> mechanism may be another useful tool to reduce render times in scenes
> with much reflection.

That's awesome, no doubt!

> > Also, it's not like as if povray wants to be a physically-based unbiased and
> > slow raytracer, is it?
>
> Well, if /I/ am asked, I'd want POV-Ray to become a physically-based
> unbiased and /fast/ raytracer :-P

That would be great.

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