We show that the smoothed particles paradigm leads to a coherent definition of the object's surface as an iso-surface of the mass density function. Implementation issues are discussed, including an efficient integration scheme using individually adapted time steps to integrate particle motion. Animation requires a linear complexity in the number of particles, offering reasonable time and memory use. Mass density is represented in grey-levels. A quasi liquid material is falling under gravity between two rigid obstacles.
Mass density is represented in grey-levels.