This chapter draws on light art projection festivals and 3D projection mapping in the Asia-Pacific to examine ambient participation and critically develop a methodology for placemaking. Placemaking is generally referred to as a practice of enlivening a place through arts and cultural activities. A key beneficiary of creative placemaking is the increasing popularity of the urban screen. As large screens in public places, most make use of projectors to cast light onto irregular surfaces like building facades. The term ambient participation is first used in cultural impact and audience development studies to understand the motivations behind why people participate in the arts. Ambient participation is included as one of five modes of arts participation; other modes include inventive, interpretive, curatorial and observational. To extend the theorization of ambient participation as a value-laden mode of arts engagement, it is also useful to return to theorizations of ambience in cultural theory, social informatics and phenomenology.