I've run into an interesting problem. I was messing around with a scene.
No real purpose in mind. Just playing around. Anyhow, I wanted to have a
light shining out from under a clipped sphere, and use media to give the
light a glow.

I set up the scene with several lights, but only the light under the
sphere has media_interaction set to ON. I gave the light a fade_distance
and fade_power with the intention that the media effect would fade away
a short distance beyond the clipped sphere. I then used a cylinder
container for the media and set the thing to render. The effect was not
what I expected.

It "seems" that the fade_distance and fade_power are causing the media
to invert itself. ie, the media does not disappear as the light source
fades off. instead, it changes from white to black. Now this ends up
looking kind of cool in this instance, but it may not always be wanted.

Am I missing something obvious? I was using scattering media without
absorption or emitting. I'll post the image in p.b.i.

David
--
Keeper of the family pets.
"You want fish? I got fish. I got fish, and eels, and turtles, and
snails, and frogs, and dragons and cats..."

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David Heys wrote in message <389214A3.136337DC@gci.net>...
>It "seems" that the fade_distance and fade_power are causing the media
>to invert itself. ie, the media does not disappear as the light source
>fades off. instead, it changes from white to black. Now this ends up
>looking kind of cool in this instance, but it may not always be wanted.
>
>Am I missing something obvious? I was using scattering media without
>absorption or emitting. I'll post the image in p.b.i.


Try setting the "extinction" parameter of the media to 0.  A scattering
media is similar to a combined emitting and absorbing media, with the
"extinction" controlling the absorption part.

Mark

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