Ever seen a 3D printer that used water as its medium? For director Cole Paviour and production studio Unit 9, London's Machine Shop created a rain rig that could precisely dribble out 3D animated scenes, one frame at a time, using water drops as pixels. The life-size animated figure was based on motion-capture data and captured using a Mark Roberts Motion Control Milo rig synchronized with the water, flash lamps, and camera shutter. The camera, by the way, is ARRI's Alexa 65, specially modified to output a TTL pulse to help keep everything in sync. The spot won a Golden Lion last month at the Cannes International Festival of Creativity. For more about how they did it, watch the behind-the-scenes video below and read backgrounders on the shoot from Unit 9 and ARRI.