Understanding the interaction between dynamics and geometry is crucial to capturing commonsense physics. This paper presents a qualitative analysis of the direction of fluid flow. This analysis is dependent on qualitative descriptions of the surface geometry of rigid bodies in contact with the fluid and a pressure change in fluid. The key problem in designing an intelligent system to reason about fluid motion is how to partition the fluid at an appropriate level of representation. The basic idea of our approach is to incrementally generate the qualitatively different parts of fluid. We do this by dynamically analyzing the intereiction of geometry and pressure disturbance. Using this technique, we can derive all possible fluid flows.
