Fog and Lighting

The way the rain is lit is going to be very important. Rain is hard to pick out a lot of the time because of its transparent nature, especially when situated against a grey sky. Although the size of the rain plays an important factor - its far easier to see bigger drops - the way its lit is still the most important factor in creating a good effect.

I've also been out gathering a bit of reference pertaining to the environment fog. Now, its been quite bright here today and so the fog is a lot lighter here than it will probably end up being in the scene itself. It still serves as good reference for me however.

I am also currently reworking the scene in order to render with V-Ray, this will hopefully lead to a further improvement in render times.