A More Efficient Way

Spending a bit of time within the options in Maya, I found a more efficient way to create the rain effect. That is through the use of Motion blur.
Using an nParticle system to generate the droplets, and using a Sphere as the particle geometry with an Mia material applied (With settings in place to match that of water).
The streak like effect comes from the Motion blur which is applied to the render.

More Bifrost

Trying a more complex Bifrost simulation, mainly to see what my system can handle aswell as how to do some basic things like collisions with geometry. It is an impressive tool, and I want to see if it can be used to create rain, or if it can be used to enhance the rain effect in anyway. I'm thinking that it may be a good solution for creating the more "fog-like" aspects of a storm.

Rain VFX

I've found a lot of references to After Effects being used to create rain in post for certain shorter films. A lot of the references I've found for larger budget films involve the use of a special effect, rather than a visual effect. Such as in the Noah post I made earlier.

I did however find a very interesting video a while back (I forgot to post it) on how they created some of the water effects in "Battleship". Its a very interesting video, and I feel that a lot of this could be applied to some rain effects. I have also been spending a bit of time in the new Bifrost system within Maya 2015, figuring out a little bit about the system. Within a few minutes I managed to put together this very basic simulation.
Taking this further, I would like to try and work something like this into my rain scene.

Rain Issues

This effect is proving somewhat impractical to render. Mainly due to the heavy use of Refractions in the materials. I think that with some tweaks to the lighting, the actual effect will look allright though.
I have attempted to render it in realtime using a CGFX shader, but this did not work either.

I am going to try reducing the fog effect to see if that is an acceptable solution.
Oh, and I do want to try some water effects within Maya 2015's new Bifrost system.

https://www.fxguide.com/featured/bifrost-exclusive-first-in-depth-look/

More research

So, while looking up some VFX videos I came across this one. Its got some advice in it that i shall be working into my setup. Such as back lighting the rain more. I will either crank up the sun or add in another light for such purposes.

More Rain Atmospherics.

Yet another render of the fog atmospherics. Playing about with silhouetting some geometry.

I would like to try and simulate a lightning strike as-well.
I really need to try and lessen the render times though, as rendering the volumetric fog as-well as layers of refractive material takes a long time.

Fog and Crepsecular

In adding some more atmosphere to the scene I changed the way the fog works.
Now there is another particle system consisting of sprites that have a fog texture/material applied to them, however there is also an environment fog pass shader in the scene to add just that bit more overall.

I also decided to add a strong light to simulate the sun shining through the fog, which lead to some really cool crepsecular (god ray) effects.

All passes rendered together.

The environment fog pass.

The ground model pass.

The rain pass (including IBL background for refractions)

The sprite fog pass.