Specifying and Generating Editing Environments for Interactive Animated Visual Models

Abstract

The behavior of a dynamic system is most easily understood if it is illustrated by a visual model that is animated over time. Graphs are a widely accepted approach for representing such dynamic models in an abstract way. System behavior and, therefore, model behavior corresponds to modifications of its representing graph over time. Graph transformations are an obvious choice for specifying these graph modifications and, hence, model behavior. Existing approaches use a graph to represent the static state of a model whereas modifications of this graph are described by graph transformations that happen instantaneously, but whose durations are stretched over time in order to allow for smooth animations. However, long-running and simultaneous animations of different parts of a model as well as interactions during animations are difficult to specify and realize that way. This paper describes a different approach. A graph does not necessarily represent the static aspect of a model, but rather represents the currently changing model. Graph transformations, when triggered at specific points of time, modify such graphs and thus start, change, or stop animations. Several concurrent animations may simultaneously take place in a model. Graph transformations can easily describe interactions within the model or between user and model, too. This approach has been integrated into the DiaMeta framework that now allows for specifying and generating editing environments for interactive animated visual models. The approach is demonstrated using the game Avalanche where many parallel and interacting movements take place.