Hello wushen.

I made a couple of rain models that are long sets of rain drop meshes that can be very simply "animated" in Vue by dropping the set (a single object) slowly down before the camera. The rain drop meshes in the set consist of thousands of individual droplets and streaks, and they are of different densities, depending upon how heavy the rain needs to be. The "set" is generally cylinderical in shape so that it can be used at any horizontal angle relative to the camera - and it is fairly deep so that the rain drops will look photo realistic, and will catch light and cast shadow accurately. 

For Vue, I have posted this as a free object. I am away from home at the moment, but will try to locate the download link and post it here as soon as possible.

Splashing rain drops are an entirely different matter. When the rain drops impact a solid surface and "splash", it is because they are breaking into small bits upon impact and are bouncing upward. It is possible to create meshes that look like this in both the static form (and in animation form if you have Maya, MAX, XSI or Lightwave), but this is done by creating thousands and thousands of polygons. So, there has not been a lot of call for this kind of product.

The splashing rain drops in still mesh form are available in that "Stormy Rain" product. There are versions available for Vue and for Poser. (I don't remember if both versions are available here on Rendo, but I think I can access both versions from my own web site if you want one of those.) And the versions of splashing rain in that product package consist of light rain, medium density rain, and heavy rain (both slanted and coming straight down). That product package also contains sets for ripples that can be placed on the ground or a pond surface or something like that.