This paper describes a framework for a collaborative, dynamically modifiable product model called FREAC built for the purposes of experimental software development. When developing FREAC, we attempted to realise the following properties that are typically lacking in currently available commercial systems: first, a high degree of flexibility so that it is highly adaptable to the needs of different disciplines, second, the ability to seamlessly connect different tools, third, real-time concurrent modelling by different remote partners, fourth, the ability to save a record of the entire modelling process, fifth, dynamic extensibility both for software developers as well as for the end users of the respective tools.