> This would be object-specific antialiasing. It has been discussed
> some days ago, it's not even trivial to define it, what should
> happen with reflections, refractions, semi-transparent surfaces...?

My thinking is just what I said.  If a pixel has a ray (any ray be
it a reflected, refracted, or transmitted ray) penetrate the object's
bounding box then that pixel uses the specified AA.  Sounds
simple enough to me but putting it in place I'm sure is anything
but simple.  I can define it though I think.

> But, somehow, I guess assigning the specifici antialiasing settings
> to simpler "bounding objects" would make it a bit easier (the
> problem with fine grids could be "solved")

I'm not familiar with the "fine grids" problem.  Being new I think
I missed where this was talked about before.  In the
implementation I'm envisioning you'd set a global type of AA that
was used if no bounding boxes(BB) with there own specified AA
were seen for a given pixel.  Such as is done now.  The global AA
could be no AA at all.  For pixels that saw one or more BBs with
specified AA you'd pick what ever specified the most AA be it
the global setting or the setting from one of the boxes.  The default
AA on a BB would be no AA and you'd have exactly what you
have now.  That's just my 2 cents.  As I've still got alot to learn
I'm probably way over simplifying the problem.  But as the test
for the intersection of rays with BBs is already there (That's what
the BBs are for isn't it?) it to me sounds like something that might
not be too hard to add.  Hmmm... are reflected, refracted, and
transmitted rays tested against the BBs as well?  I'm not 100%
sure but something makes me think I've seen this talked about in
the documentation.

> Remember a POV-plane is not infinitely thin, but infinitely
> thick, it divides the whole space in two regions: outside and
> inside.

Thanks.  I didn't know that.  I haven't played with planes much
yet in POV-Ray.  I've used them as floors on sceens but that's
been it so far.

> Two intersecting planes divide the whole space in four regions
> (inside both of  them, outside both, inside only one and inside
> the other; the first would be the "intersection"), these are still
> infinite, but they're not infinitely thin, they have two faces: the
> surfaces of the planes. An intersection of four planes could (if
> they're are properly arranged) define a tetrahedron, this would
> be a finite shape made from infinite planes, and it certainly has
> some volume.

I follow.  That also explains Andew's comments too.  I was just
about to tell him that the intersection of 3 planes is a point and
that 4 is usually nothing.  I just haven't used planes in CSG's yet.
I think if I had an occasion to make a tetrahedron before I'd have
defined it as a prism.

Thanks,
Carl

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