Abstract. Natural systems, such as organs and organisms, are largescale complex systems with numerous elements and interactions. Modeling such systems can lead to better understanding thereof and may help in efforts to save on resources and development time. In recent years, our group has been involved in modeling and understanding biological systems, which are perhaps the prime example of highly complex and reactive large-scale systems. To handle their complexity, we developed a technique called reactive animation (RA), which smoothly connects a reactive system engine to an animation tool, and which has been described in earlier publications. In the present paper we show how the basic idea of RA can be made generic, by providing a simple general way to link up any number of reactive system engines -- even ones that are quite different in nature -- to an animation tool. This results in natural-looking, fully interactive 3D animations, driven by complex reactive systems running in the b...