Am 06.01.2017 um 04:48 schrieb David Buck:

> It may not be related (media was after my time with the product), but in
> the early days of POVRay we'd often get "speckles" on objects.  They
> were usually black pixels.  The problem was floating point precision and
> was corrected by adjusting the epsilon factor to determine how far away
> from one intersection point counts as a separate hit versus the same
> hit. For example, if a ray hits a sphere, and we trace another ray back
> to the light source to determine if we're in a shadow, it's possible
> that the first ray's intersection point was slightly inside the sphere
> and the ray back to the light source hits the same sphere on the way
> out.  This would count as a shadow and would make a dark pixel.
> 
> This bug in media feels very much the same to me.  I wouldn't be
> surprised if it's a problem with precision - especially seeing that
> scaling the scene eliminates the problem.

Actually it's pretty much the opposite: These media speckles are
essentially a side effect of the very mechanism by which those dark
pixels are avoided.

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