I create a box based emiter and set up all the parameters to make it rain (size of particle, colour..etc) but the when I was watching the "rain" the rain drops seem to fall in the same location and don't seem to be random with in the emiter area..
(sorry, bad explanation...trying to eat pizza, drink coke, code and type this in without thinking...
Also with regards to particles, in the above situation, when you are out side the particle area they appear nice and long'ish (just like rain, sort of) but if I step into the 'rain fall' and either look up or down, they still fall down, but they appear to have a billboard type effect, where the rain streak is parallel to the viewing plain..