How does one spread thousands of small water drops over a surface? One of the most challenging tasks a modeller can face is the creation of realistic water drops or liquid sitting on top of a surface.
Surface-to-surface contact renderings are a tough task for even the world's best raytracing solutions.
As of this writing, finalRender 3.5 SE is the only raytracing system to offer special support for Surface/Surface contact situations when rendering refractive or semi-refractive material properties.
By looking closely at the drops one can see the reflected/refracted enviroment.