Beta RC3 / Win98 / 700 Mhz PIII / 128 meg

When  rendering with radiosity, the amount of ambient light coming from
objects with a dark pigment, is not what I expected.
With a default finish, the threshold is somewhere around 0.033 for the total
of the color components.
Radiosity quality does not seem to be of any influence, however, increasing
the diffuse factor will decrease the threshold.

The scene shows a horizontal bar with pigment fading from black to
0.1*green.
It should show a smooth linear fade, but has a sawtooth at about 1/3 of the
ramp.
If the light source is removed, no illuminance should remain. However, the
"sawtooth" is still visible.

Can anyone confirm that this is not "expected behavior"?
If this turns out to be a flaw, can anyone confirm that it will be fixed in
the final release of 3.5?

Thanks,
Jan Maarten van der Valk

The scene............

global_settings {
  assumed_gamma .5  //make up for the low pigment values (improved
visibility)
  radiosity { }     //default settings - higher qualities do not affect the
phenomenon
  ambient_light 0
}

camera { location -z look_at z }

light_source { -z 1 }

box {
  <-.5, 0, 0> <.5, .1, .001>
  pigment {
    gradient x
    color_map {
      [0, rgb 0 ]
      [1, rgb <0, .1, 0> ]
    }
    translate -.5*x
  }
//  finish { diffuse .8 }
}

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