Enabled when >0, controls the soft fading of spot and rect light edges in order to make them appear smoother, resulting in less flickering. A value of 1 is a good starting point and it means that fading will be applied over the size of 1 froxel on the screen.
Usage
r.VolumetricFog.LightSoftFading [value]
Set via the console (~) or in DefaultEngine.ini / DefaultGame.ini.
