A strategy for the production of a computer-generated animation film showing the complete motion of a human heart is presented. The model for construction and animation is discussed. The MIRA 3-D animation software was used on a VAX 11/780 computer. It is based on three main components: an object modeling and image synthesis system (Body-Building), a director-oriented animation editor (Animedit) and an actor-based sublanguage (Cinemira). The heart was separated into parts that have different functions and different motions and transformations. Each part is considered as a subactor of the heart, which is viewed as the main actor. The left ventricle simulation is emphasized, because it is based on medical measures. The atrium simulation is based on beta-spline surfaces and blood volume considerations