I have implemented a tool in Maya that has the ability to generated particle simulations that
can produce rain effects with various degrees of detail. Depending on the needs of the users. It has
three separate layers, a background layer streak based, mid ground layer sprite based and a foreground
layer blobby particle based. The system fully automates the set up of all the particles with
shaders, textures and necessary attributes. The user is able to specify target collision objects and set
up advanced collisions were particles flow along the surface of the object in a more realistic fashion.
There is also the option to set up a custom camera which has a functionality for collisions of particles
to appear on its lens.