IPCity (Integrated Project on the City) is a research project that aims to develop technical and analytical research on the use of mixed reality technologies in urban environments. The project team is made up of institutions of the public and private sector working on related fields such as computer engineering, cognitive sciences, social-psychology and cultural-anthropology, architecture and urban studies, industrial design and visual and sound arts. Researchers in urban studies have been invited as “end users” to the project team, to define the general orientation and to participate to the evaluation of new technologies. The initial work done among researchers has served as a learning period between different fields of research and has resulted in the constitution of a collective consciousness regarding the necessity to integrate questions related to city making practices within the project. Existing studies on urban projects, decision making processes, public participation and the question of communication medium, as well as teal members’ field experiences have been used to deconstruct project making processes and communication issues: this work has allowed researchers to evaluate the potential of existing technologies in relation with recent evolutions in city making practices and to propose a framework for collective work. The technologies have become within this context both the research question and the basis of a reflection on recent evolutions in city making practices. The MR technologies developed by the IPCity team enables stakeholders to communicate using a multi-sensorial language where visual content plays an important role along with others such as speech, sound and written expression. They allow participants to annotate directly a scene, to inquire about the project, to communicate sensations, to discuss on notions of ambience and to share one’s experiences. The capacity of these technologies to gather stakeholders on the project site, under a roof (that of the MR tent), around a table ( the ColorTable) with several direct views of the site (windows, mobile cameras, panoramic views) constitute a plus which amplifies the sentiment of convergence and collective action.