Scattering media behaves quite strangely when you put
a light_source directly into it.

Consider following scene, a box containing scattering media
and a light source just above it:

camera { location -30*z look_at 0 }
plane { y, -15 pigment { checker rgb<1,0,0> rgb<0,1,0> scale 10 } }
light_source { 10.1*y, 1 media_attenuation on }
box {
  <-10,-10,-10>, <10,10,10> hollow pigment { color rgbt<1,1,1,1> }
  interior { media { scattering { 1, 0.2 extinction 1 } } }
}

Rendering it gives what one expects: glow in the upper part
of the box, the lower part being almost dark since little
light come there (most is scattered).

But changing the third line to

light_source { 9.9*y, 1 media_attenuation on }

i.e. putting the light source inside the box, makes the media
to emit an abusrd amount of light.

I hope I didn't miss anything, but is this the way it's
supposed to work or is it a bug?  I'd expect the media to
behave more physically.

Yeti

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