Am 30.04.2018 um 07:12 schrieb Sven Littkowski:
> Look at the two attached imagea. I have white lumber, but when using
> radiosity (1st image), the white lumber glows and simply emits too much
> reflected indirect light. The 2nd image shows the same scene without
> radiosity.
> 
> is there a way to reduce the amount of reflected indirect light?


* MAKE SURE you're not just using an overly bright light source and/or
environment (sky sphere, background, whatever)! Turning on radiosity in
a scene that has a lot of bright surfaces WILL typically increase the
overall apparent brightness -- which is not radiosity's fault, but
rather that of the "poor man's" alternative, the `ambient` parameter,
which is usually set to a value far too dim for white surfaces.(*)

(* BTW, technically the `ambient` parameter shouldn't be set according
to the material itself, but rather according to the environment of the
particular object(s) that will be set to this material.)


If that isn't the issue, ...

- Make sure you're not using `emission` in the material finish.

- Make sure you're either using `#version 3.7` or later, or you're using
`ambient_light 0` in the global settings, or you're using `ambient 0` in
the material finish.

- Make sure your pigment is not unrealistically bright. Real-life
"white" paints are typically around 0.95, real-life "white" woods are
probably closer to 0.6.

- Make sure your `diffuse` setting is not unrealistically high,
especially in combination with `reflection`. When using `fresnel`, it is
ok to set both diffuse and reflection as high as 1.0 (presuming you're
properly controlling the brightness via the pigment); otherwise, the
/sum/ of the two should not exceed 1.0.


Also -- but this should be self-evident, ...

- Make sure you're not using an excessively high `brightness` value in
the radiosity settings ("excessively high" being anything noticeably
higher than 1.0).

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