Tweak suggested energy values to simulate volumetric lighting in Volumetric fog
4.6 has fixed the previously incorrect volumetric fog blending behavior.
This has the side-effect of making bright volumetric fog look significantly
brighter than before. To get a result similar to the previous look, the
Volumetric Fog Energy property on Light3D nodes needs to be reduced significantly
(often by a factor of 10, if not more).