Urban design today faces complex demands. It has become a necessity to negotiate between stakeholder objectives, the expectations of citizens, and the demands of planning. In this paper we describe how we use a set of participatory technologies in combination with methods for preparing and enabling a heterogeneous group of participants to create a vision of an urban project. Our observations show how space, materials, and different types of content affect participants' collaboration and their debate of the urban issues. We discuss how these participatory technologies and events may help build a community of practice around an urban project. Categories and Subject Descriptors H.5.1 [Information Interfaces and Presentation]: Multimedia Information Systems