Not that I understand all this any but the interactive part sounds like
it was intended to do just that, interact with the media in a normal
way. The little I've done in this regard doesn't allow me much insight.
But I understand your predicament there. Obviously the workings of media
allow for absorption to create a shadow by simple interaction with a
light and attenuation is only to fade.
But I'm not going to try and remember what the behaviours all are, Id
rather do some checking of this myself before committing to a judgement.
Keep in mind though what you say makes sense though could easily be a
observation of what was intended. No doubt since the transmit lacking a
shadow and all that as many of us know, there's possibility of
incorrectness in the thing elsewhere.

Margus Ramst wrote:
> 
> I understand what media_interaction does. The problem is, even when light is
> not scattered by media, the media still casts shadows!
> 
> IMO, the correct behaviour would be the following:
> 1) interaction on & attenuation on - light is scattered and attenuated (the
> media casts shadows, unto itself and other objects/medias);
> 2) interaction off & attenuation on - light is not scattered but the media
> still casts shadows from this light source;
> 3) interaction on & attenuation off - light is scattered, but _not_
> attenuated, i.e. the media casts _no shadows_ from this light source, not
> unto itself, not anywhere else;
> 4) interaction off & attenuation off - the media is not affected by this
> light source in any way.
> 
> Because of a pseudo-bug in transmit, conditions 3) and 4) behave in the
> described way when the container objects uses transmitted transparency
> (regardless of media_attenuation setting). But with filtered transparency,
> media casts shadows under all of these conditions.
> All in all, I cannot see any difference in the rendered image, whether
> media_attenuation is on or off.
> 
> Margus
> 
> Lars W. wrote in message <3711dff8.0@news.povray.org>...
> >The Point for the media_interaction parameter is that
> >you can exclude some of your light sources from the media computing
> >process, let's say you have a scene with one primary light ( The Sun )
> >and you have an media object ( some clouds ) and then you have many other
> >lights, with fade_power and distance assigned, which never reach the
> clouds,
> >then you can turn the media_interaction for those lightsources off to get
> >faster rendering times.
> >
> >i think thats the only reason this feature exists.
> >
> >by the way does anybody know how to turn off recieving shadows
> >with scattering media ?
> >
> >greetings Lars
> >

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