This thesis presents a study of what is required for a computer system to support human creative collaborative design activity. The field of design study is targeted on architecture. Design is seen essentially as an activity of modelling complex objects with or without computers. 'Teamwork in architectural modelling' is, therefore, the realm of inquiry, with the goal of identifying the representation and communication requirements for computer support. A phenomenon of collaborative design to be explained is how the distribution of design work among multiple participating expertise is related to the integration of individual design contributions into products with architectural unity. Several historical cases of building design projects are studied. We examine the design expressions produced by members of the design team in each case. Based on the results of case studies, we put forward two distinct teamwork patterns in collaborative design: metaphorist and structuralist. The teamwork patterns are subsequently treated with more elaborate analyses and simulations. Prior to the presentation of the requirement studies, a survey of the current state of the art in building collaborative drawing and design support systems is provided. The survey shows that our concern of supporting collaborative design modelling remains a subject largely unexplored by the current system designs. For each teamwork pattern identified, a situation-theoretical framework is adopted for carrying out a more elaborate analysis.