Fast product follow-ups and increasing customer demands have changed product design from a rather unstructured process, into a systematic activity. Nowadays, both companies and researchers have developed the organizational aspects of integrated product design. However, attention to the collaborative aspects lags behind the structural and organizational aspects. The aim of this study was gaining a better understanding of the collaborative processes of actors from different disciplines during the product design process in industry. We called this process collaborative design. Collaborative design consists of three building blocks: - knowledge creation and -integration between actors from different disciplines - communication between the actors about both the design content and the design process - the creation of shared understanding about the subjects communicated In this thesis, we focused on the third building block: the process of creating shared understanding between different disciplines about the design they were making. During empirical case study research in industry, we investigated what factors influence the creation of shared understanding between actors in collaborative design projects. Additionally, we examined the collaborative mechanisms that occur in these projects. Collaborative mechanisms describe what influence the factors found have on the creation of shared understanding have on the three building blocks of collaborative design. The results of thesis form a significant step towards a better understanding of collaborative design processes in industry.