Am 18.02.2016 um 20:29 schrieb Stephen:
> I’ve named this Sven’s Bug because I noticed it running his code posted
> in “15 Shapes Taking Forever” in povray.general
> And so he gets his name on something. :-P
> 
> There is a difference between renders with and without using Render
> Block Size.
> The images are with the windows QUICKRES.INI [800x600, AA 0.3] with and
> without +BS8
> I compared them in PaintShop Pro (XOR shows it best)

Nothing in there that would surprise me.

I see some tiny fluctuations in the results, which are normal -- and a
few more pronounced differences at the objects' edges, which are quite
obviously related to anti-aliasing.

POV-Ray 3.7 performs anti-aliasing at the render block level, /before/
assembling the blocks to an entire image. As a consequence, the decision
to supersample any given pixel not only depends on the neighboring
pixels, but also on whether the pixel is at a block boundary.

Consequently, reducing the render block size, and therefore adding more
block boundaries, will change the behaviour of anti-aliasing, and
increase the risk of aliasing artifacts.

So this is not a bug, just a drawback of how things are implemented.


(Hey, what do you expect if you associate Sven's name with it?! :P)

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