Hi i am working on a concept and i have a rainy sence and i am wondering how do you think i sould go about doing it?. i am needing this rain to be vary real to be able to zoom in on it and i also need the rain to effect pudels and form pudels i have considerd useing fluid sim or soft body dupeliverts but still cant get the result i need any ideas?
sounds a bit hard…there is a tutorial somewhere on the blender.org for making rain drops…as for the pudling thing…its a bit hard, i think there is a new feature in 2.4 (not sure) so you can make moving abjects affect it.
So what i would do is make the raindrops softbodies so it will fall, and then making liquid with the fluid sim, or even better make both fluids
so, use the inflow button for the raindrops (play around to get drops) and well…there you go, just make loads of tiny fluid drops (spheres or watherever, and add inflow, and let em go!! 
well can softbodys and fluid sims mix?
i dont think so somebody might be able to correct me though
well im not going to take the word of sombody that says 2+2 = 6 
j/k. well i sure would like to get spectaculer rain going on i tryed softbodys and fluid sims it dont looks like thay work togeather from what i have seen but im still vary new to both tools so i may have done somthing wroung?
Maybe try using a mesh raindrop with soft bodies enabled on it. Then parent it to an emiter mesh. Activate dupliverts and tweak the particles to get the desired look. Maybe texture the ground with the water plugin to make it look like the rain is rippling too.
well i thout about that and it works with some success but it dont do jack for pudels witch is whats fubaring me i am going to be doing a close up where it starts to rain and you see the first drop strike the ground and the ground and you see the drop of water splash agisnt the concreat then it zooms out and the rain starts to fall like crazy making the ground wet and creating pudels that riple every time a drop hits it and i am pritty dang sure that soft bodys wont do all that i no thay will do the first drop and all the rain drops affter its the pudels and the nice wet look witch i will pry use like a metiral for but i still wont you to actuly see every rain drop bounce off the ground and make that nice splash look
I’m not at all experienced with the fluid simulator, but maybe you can make a short scene with a few drops being fluids, then as you zoom out change it to just the water plugin texture.
make everything with the fluid sim…make loads of spheres, activate them all as fluids inside the domain, and put them as inflow, then change the inflow speed and stuf untill you get the right effect (untill all of them falls lowly out so it drips) then put all the inflows at the top of the domain and let em go, they will then fall on the bottom of the domain (ground) and start making pudles. you can then alo go and change the ‘real size’ of the domain to make it look realistic
The only problem i see with this…is computer performance…its going to take a while to bake and render it, so be prepared when your pc crashes or something
Here is my idea which I think would turn out rather well (I spent some time thinking about this problem a while ago). It would require a little effort though…but hear me out.
Use a fluid sim for the first few drops untill enough fluid has accumulated so you have a more or less level surface (ie a small a puddle). Once the puddle is relatively flat on average as drops bombard it, you could stop using the fluid sim and switch to the next level of illusion…
The next step is to relax the mesh of final surface till the surface is completely flat over a couple of frames. From now you can enlarge your puddle by literally scaling it up in size over your animation.
But the puddles are flat! How do we get round this? Well, here goes…
You rain drops which were originally modelled as part of a fluid sim change to being controlled by a dupliverted particle system. A duplicate and identical particle system to this one exists and overlaps it. Empties form the dupliverts for the second system and raindrops for the first obviously. Nothing too hard yet…
Now for the clever bit…
Find the build with Pytex (python textures) on blender.org. Now write a script that searches for the empties and when they are below the level of the puddle surfaces, the scripts generates a wave texture at that origin.
Use this texture as a displacement map to generate geometry ripples. Voila!
The point about using Pytex would be that ripples aren’t randomly generated…they are generated when the drops hit the surface. I’m sure this could be VERY convincing…especially if you switch on motion blur for the rain falling.
Koba
P.S> The initial drops for the fluid sim need to have a high velocity and no acceleration (they have reached terminal velocity). Make sure the drops from the particle system have the sam velocity on impact.
Sorry for the double post but I have some more suggestions:
-Use the ouflow a bit for the initial sim. This will help make it look like the ground/Earth is absorbing some of the water.
-You could use Pytex to make dark splotches where the rain hits the earth/tarmac for example. This would be affecting the colour of the surface only.
-If it a road or something, make sure you keyframe the reflectivity of the ground over time.
If you keep at it you could have something REAL impressive! (This is the sort of thing I would do if I had more time/motivation)
Koba
well i have read all the post here and thay rock keep them coming :D. at anyrate i cant seem to figure out how to get inflow and out flow to work could you guys shead some light on getting this to work?.
never mind i figured out how to get inflow to work i am going to try out a few of these consepts i will post my results if anybody has any other great ideas i would be vary greatful for them 
i have noticed this guy seems to make some tight fluid sims, i have been studing his idea his is simuler but he is taking advantage of the new fluid sim options, and he was useing like a chease grater effect where as i was shooting fluid in the air and bouching it off the roof making it scater i like his idea better, i have been useing some of his ideas in my work, thanks for the reffrance, i am do to post a new animation i am working on i just havet had time to render i will post when i get it done.
chrome.