I spent a few hours trying to find a solution... I'm looking to get the effect of atmospheric perspective in my scene to help me understand lighting more. I have an HDRI and I'm using cycles and I've tried the following....
Add a volume scatter to the "Volume" tab in World properties. This breaks my HDRI and it just renders black even with a density value of 0.000015
I tried creating a large sphere encompassing my whole scene and adding a Volume Scatter shader to it. Scene renders, but there is no sun lighting from the HDRI, just dark blue ambient lighting it seems. I tried adjusting the density value to around 0.00001 and I can either get the scene to render normally with no atmospherics or as a dark scene described earlier.
Is adding atmospheric perspective in Blender 2.79 possible?