Chapter Z Persuasive Artefacts in Architectural Design & Planning Ina Wagner Z.1. Introduction Architectural design and planning is a collective activity, embedded in a community of practice. At the heart of the work, therefore, is the need to share materials and to mobilize support. Sketches, scale models, images, plans, etc. have a crucial role in this process. They are created and used for expressing, developing, detailing, communicating, and presenting an evolving design concept (Henderson, 1995; Perry and Sanderson, 1998). One of the most important advantages of such visual and graphical material lies in its ability to create ’persuasion’ and to invite others into a dialogue (Latour, 1986). We have explored architects’ uses of inspirational objects (images, sound, video, animation, 3D objects) for forming ideas, expressing qualities, and for convincing others of the viability and power of an idea. Such inspirational material is open to diverse levels of interpretation and understanding, stimulating contradictory and surprising associations (Büscher et al., 1999). The availability of digital media increases the possibilities of architects to create and share visual materials. Techniques such as rendering, computer animation, and modeling provide a new visual language. At the same time, issues of how to combine digital material with tangible artefacts and how to support fluid transitions between both media come to the fore. This paper examines the role of ‘persuasive artefacts’- both digital and tangible - for cooperation in architectural design. Z.2. Visual material in use Ongoing long-term fieldwork in an architectural office is used to analyse the role of ‘persuasive artefacts’ in cooperative work. Fieldwork material has been collected over a time-span of almost two years through ethnographic observation