A question on the forum a short while ago was about volumetric sun through a tree. Whilst looking at this I noticed a couple of things... Both of the pictures above are rendered at 'final' level, and both have volumetric atmospheres and sun (set to 10 in volumetric strength) The one on the left has the 'fog and haze' and the 'volumetric sunlight' quality boost sliders set to zero. The one on the right has both of these quality sliders set to plus 2. 1. It said (I think) in the manual, that there is no need really to adjust these quality sliders, as the quality is automatically altered as you switch between preview, final, broadcast, and so on. Has this feature been disabled? - because the one on the left, rendered at final, is far from optimum in terms of quality settings. 2. Anyone any idea why there is such a strong bunch of 'rays' in the left hand image, with quality boost set to zero, and yet the rays have virtually vanished with quality set to plus 2. I would have thought the shadow-ray contrast should be the same, just much less noisy. If I set the quality to 4, the maximum, all trace of volumetric shadows in the atmosphere vanishes, which seems a bit odd... Any one got any comments?

I was having that same problem when doing my explosion in the nova picture... I solved it by using a spotlight, and turning the haze/fog effect down more and not touching the volumetric setting from the default. See if that helps any.

I think that the quality slider of volumetric settings acts more or less, like soft shadows : With no soft shadows, the limits of shadow appears really straight, like the volumetric shadows in your first picture. With setting of soft shadows, the limits are blurry and, very high soft shadows can make them almost disapearing, like volumetric shadows in your second picture. The problem is that volumetric sunlight are hard to set correctly and faking it with spotlight, directional or pointlight usually saves a lot of wasting time and pain...