RealFlow is a fluid and dynamics simulation tool for 3d animation and the standard environment for animating water. Many of the case studies on the RealFlow site show samples of moving liquids (more compelling graphically) but it can also be used to simulate underwater spaces. The the program is particle based: physical properties control the particles’ behaviors and their interaction with each other, as well as extraneous impulses, forces and accelerations. It can also calculate buoyancy of objects and simulate their motion in water. It seems that the transition to particle based animation environments (versus layer based or object based) allows for new types of simulations of environmental conditions, and thus new modes of underwater mediation.
RealFlow has been used for animation in a variety of feature films, including Poseidon. In 2007, the creators of RealFlow were awarded the Technical Achievement Award from the Academy of Motion Picture Arts and Sciences.