Building on an in-depth ethnographic study and the approaches of ‘practice-based studies’ and ‘science and technology studies’, the role of visual representations is explored in briefing and design processes. Three characteristic ways in which drawings contribute to ongoing negotiations are discussed. First, drawings are shown to be inscribed with particular interests, making them political instruments. Second, they have prescriptive effects as partially independent actors in the project. Third, they are shown to participate as conscriptions in a complementary process of inscription and prescription, changing their roles and configurations, and intersecting and affecting the project process in characteristic ways. Visual representations play a temporary role, and ‘time’ and ‘phase’ set boundaries for them. For practice, the analysis suggests the implication that communitarian management approaches should be chosen to promote innovative briefing and design.