I've hit two problems
    i) brightness, easily solved
    2) the interaction of two medias is completely different. the media
seems to almost dissapear.This is the one where I can't find the logic. or
get any control, Now that Nathan has explained I can see why, but not how to
compensate.

Mick


"Nathan Kopp" <Nat### [at] Koppcom> wrote in message
news:39236af5$1@news.povray.org...
>
> Margus Ramst <mar### [at] peakeduee> wrote...
> > Nathan Kopp wrote:
> > >
> > > It's not the media.  It's the "noise3d" fix.
> >
> > I suspect there is something funny about media. I am working on a
> cloudscape and
> > switching to 0.5 immediately led to all sorts of weirdness. I'm still
> > researching the matter, but here is one observation: method 3 media
tends
> to
> > render as black if minimum samples is set to 1. Raising it usually
helps,
> but
> > I've had to go as high as 20 to eliminate some weird banding. Method 2
> media
> > sometimes acts up too, but overall the behaviour seems kind of chaotic
> (i.e. I
> > haven't made the connection yet).
> > Could it perhaps be connected to the constant media speed enhancement?
How
> does
> > this work?
>
> It's possible.  The speedup works like this:
>
> If the ray in question is a shadow ray (meaning that we are only
determining
> how much light is blocked as the light travels through the media) and all
> participating media are constant, then POV will use one interval, and one
> sample using media method 1 instead of the user-selected method.  The
reason
> is that no other samples are needed.  A single sample will give us the
> density, and we really don't care how much light is hitting the media
along
> the path of the ray, because we only care how much light was blocked as
the
> beam of light traveled along the ray.  Does that make sense?
>
> -Nathan
>
>

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