Among other things, Carl Hoff wrote:

> Ideally what I'd want to do I think is put a bounding box around the
> cylinder that is atleast several pixels wide (at whatever the final
> resolution is) and have a way to tell POV-Ray that any pixel that has a
> ray
> that passes through that bounding box needs to use a given type of AA. 
> I'm
> rather sure that isn't doable in atleast the current version.  It might be
> a nice thing to suggest to the powers that be though as something to
> consider
> adding.  As I've only been ray tracing a few months I really don't know if
> that's a good suggestion or not to be honest.

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...? 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 only have one infinite plane, which is the grid, and I don't have it
> making any intersections with anything be it another plane or a finite
> object.  However unless I'm missing something isn't the intersection
> between
> two infinite planes always an infinite line.  And I don't think trying to
> render that line would work.  You'd have to give it some width for it to
> show up at all I think.

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

-- 
light_source{9+9*x,1}camera{orthographic look_at(1-y)/4angle 30location
9/4-z*4}light_source{-9*z,1}union{box{.9-z.1+x clipped_by{plane{2+y-4*x
0}}}box{z-y-.1.1+z}box{-.1.1+x}box{.1z-.1}pigment{rgb<.8.2,1>}}//Jellby

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