Design has become an intense ‘social activity’: working with others and sharing a common understanding are of critical importance to find satisfying solutions for customers and stakeholders. This leads to the issue of how to set up a collaborative, model-based physical environment to foster collaboration and knowledge sharing when different disciplines get together in the ‘design exercise’.This paper describes the development of such an environment, named the ‘Decision Arena‘. It further presents the results of an experimental study involving a cross-disciplinary team of industrial practitioners.