The research presented is focused in the modelling of three main features in collaborative design using simulation models (M&S): Actors, activities and objects. To represent these features, an added value process proposition for a collaborative design in early phases using M&S was suggested. The new process was implemented and evaluated during a project at the IRT SystemX having Renault and Airbus industries as a partners of the project. The results suggest the proposed representation as highly adapted to the problem and point out the actors as the key element on the collaborative design.