There would have been two solutions to implement volumetrics in povray : the
first one (probably the one chosen in commercial packages) is to simulate
them in a user-friendly but simplistic and limited way ; the second one
(chosen by the pov-team) is to do it the hard way, by recreating real-life
phenomena. This gives (advanced) povray users a complete control on media
effects with one unique general syntax. Some media stuff we saw recently was
really amazing so the choice is good news. The less good news is that media
is obviously very difficult to master, and that simple effects are hard to
achieve and require a lot trial-and-error, noticeably for those who don't
understand the underlying physics (like me).

One solution would be for one of our media wizards to build a library of
specialised macros for particular situations. For instance, a "simple
atmosphere" macro could look like this :

SimpleAtmosphere(color, density, sampling)
with "density" and "sampling" from 0 to 1

This macro would produce a simple haze that would cast shadows and add a
nice halo around the light sources. From what I read in the povray docs,
there are many ways a halo can be produced (emission, scattering etc.), but
maybe there is one standard halo setting that would do the trick in most
situations. If this is just plain stupid, just tell me.

While I'm day-dreaming, here is a nice cloud macro...
SimpleCloud(BottomCorner,TopCorner,color,density,wooliness,sampling)
This macro would produce a ovoid cloud in the box defined by BottomCorner,
TopCorner, would of course cast shadows and be properly shadowed itself.
Wooliness (0->1) would control the sheepish aspect of the cloud, of course.

Gilles Tran

Bob Hughes wrote:

> Media for atmosphere is confounding me.
> The old way was so much better it seems to me now.
> Anyone get a reasonable, and useable, atmospheric media working for
> various situations? I.e., different camera/object distances and number
> of lights so when you make a new scene the media (as used for
> atmosphere) doesn't wreak havoc while adjusting it endlessly?
> I was taming the POV-Ray 3.0* 'atmosphere' fairly well until I moved
> along to the 3.1 chaos.
> Just curious how others are doing so far, and if there is any logic to
> it which I might have overlooked.
> I understand the basic scaling syndrome of keeping media density in sync
> with container objects, but I've been lost too many times trying the
> containerless "air", since each scene is not the same as the last.
> Well, I'll quit complaining for now. Thanks in advance for any notions
> out there you all may have.
>
> --
>  omniVERSE: beyond the universe
>   http://members.aol.com/inversez/POVring.htm
> =Bob

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