Issues and themes of Collaborative Design (CD) addressed by research done so far are so extensive that when running a project of collaborative design, people may lack directions or guidelines to support the whole picture. Hence, developing reference architecture for CD is important and necessary in the academic and the empirical fields. Reference architecture provides the systematic, elementary skeleton and can be extended and adapted to diverse, changing environments. It also provides a comprehensive framework and enables practices implemented more thoroughly and easily. The reference architecture developed in this re-search is formed along three dimensions: decision aspect, design stage, and collaboration scope. There are five elements in the dimension of decision aspect: (1) participant, (2) product, (3) process, (4) organization, and (5) information. The dimension of design stage includes three stages: (1) planning and concepting, (2) system-level design and detail design, and (3) testing and prototyping. The dimension of collaboration scope includes three types of collaboration: (1) cross-functional, (2) cross-company, and (3) cross-industry. Because of the three reference dimensions, a cubic architecture is developed. The cubic reference architecture helps decision-makers in dealing with implementing a CD project or activity. It also serves as a guideline for CD system developers or people involved in the design collaboration to figure out their own responsibility functions and their relations with other members. Demonstration of how to use the reference architecture in developing design collaboration activities and specifying the details for cross-company CD is also provided in this research
