Here is a test render for a project I am working on. In order to reduce render time, I decided to run a 2D composite in AE this effect rather than doing a full Cycles render.
What i did was set up an SPH system with dynamic paint. I then processed the result using Turbulent Distort to add some wiggley variation, and CC Vector Blur to improve the natural feel. I then generated arbitrary UVs using Colorama (a sort of phase modulated ramp) and used this to apply a Distortion Map and a vector map on a CC Vector Blur to the background image. Track matted using the original b/w composition and blurred in the background.
I am quite impressed by the SPH solver’s ability to simulate the rain patterns.
I do not really do tutorials, and I don’t have time right now anyway. But as far as the sim goes, it’s pretty straightforward.
You’ll need a fluid particle simulation with a slightly increased repulsion. If your simulation is too small, the particles will explode in all directions, you can adjust this with the size parameter.
From there, it’s just a matter of aiming the emitter at a plane or cube, turn on collision, turn up “stickiness”, adjust dampening and friction until it all looks right. Unwrap the plane. A simple planar map will be fine. Then get any old Dynamic Paint tutorial and set up that.
You’ll have a series of PNG or EXRs which you can pull into whatever software you’re using. I do not know how you’d export normals, though I am sure you can, though I am not sure that they’d quite be what you’ll need.
