In my situation, I want to render many narrow spotlight all overlapping in mist.
You can see in this image how all the spotlights overlap. The rendering I'm trying to produce is a simulation, and therefore I want to keep the geometry mostly as it is.
I've tried a few approaches:
Use spotlights into a volume
The issue here is that the minimum angle of a spotlight in Blender is 1 degree, which is still too large for me! (My spotlight should be 0.5 degrees)
Blender Render / Volume emit cylinders + Scattering volume
Perhaps the 'emit' object are also casting a shadow.
Cycles Render / Volume emit cylinders
Get a better result (the areas of most overlapping aren't the darkest). But still getting some black parts.
For Blender Cycles, I also tried disabling Ray Visibility settings on each beam object for
- Volume Scatter
but the result is largely the same