Hi,
I work on a set of scenes including some rainy ones. The whole result is acceptable, but I miss some light halo around lamps quite much, and somehow, despite some glow effects the lights are quite dead. Enabling spotlight halos doesn’t seem to be an acceptable sollution, I search something that has
A good falloff (depending on both the distance from the light source and deviation from its axis)
Some cast shadows that can be seen propagating in the air. (For interior scenes, I think it’s quite common, I have seen such things in Blender renderings)
The two effects don’t have to be the same
(PS. I use Blender internal renderer and don’t plan to switch to cycles)
For good volumetrics you need something like Luxrender that can fill air with particles, or have a “medium”
For you, really easy, create a truncated cone or a sphere depending on the lightsource, place at light, assign a gradient texture and make it transparent.
You might even use a plane and use “billboarding”. Texture the plane with a transparent halo, make it face the camera with a track to constraint.
Fake your way around, people just have to get the feeling it could be real
You definitely have to fake it with multiple spotlights or use texture mapped gobos to get good results. Hopefully we’ll get volumetric effects in Cycles relatively soon.