Rendering animations requires data structures which allow for an easy handling of the movements and changes in the scene. For a sophisticated renderer, it is very important to access the information describing the motion of the objects, because such knowledge can be used to reduce the render time. We describe an animation model based on an annotated graph, on definitions of dimensions and on implementations of functions. The data structure with its simple interfaces provides an easy to use instrument to produce computer animations. On the one hand, the model is almost independent from a static modeler and a final renderer, but on the other hand, it can be adapted easily to the needs of a specific project. In the current implementation an artist needs to work closely together with a programmer.