This paper discusses two aspects of artefacts in the design process. The first is how artefacts can be used to inform researchers about people's context, desires, concerns, needs and constraints. The second is how artefacts can facilitate the construction of shared knowledge that is needed during multidisciplinary research projects.Theses two ways of looking at artefacts will be discussed mainly through the empirical material of the interLiving project, a 3-year multidisciplinary cooperative design technology development project and also through several cooperative design workshops conducted at CID, Centre for User Oriented IT Design.