While I didn't actually produce any of the shaders used in the final film, I was lucky enough to work on Piper for a short amount of time to do look-development for some of the water ripple effects. I used Maya's ShaderFX to create some realtime-shaders in the maya viewport. I used a series of scrolling textures and noise-distorted manifolds layered together to create the effect, with controls to affect the speed, size and spacing of each texture. Eventually an FX artist took the compiled shaderFX code and ported it over to houdini with similar controls to work on top of their water sims.