Nottingham Trent University (NTU) textile, fashion and interaction practitioners were invited to collaborate with a Danish dance group to contribute a collection of costumes for performances concerned with emotion and the senses, with the ultimate aim of understanding the qualities of audience engagement with dance. This paper discusses the designers’ use of play as a methodology, and its relationship to the philosophical notion of the thing, or how artefacts are brought into being. This provides a framework for the deliberate attempt to preserve a level of ambiguity in the outcome of the design process, such that the creative engagement of other stakeholders is explicitly supported. Epistemological and methodological developments have been the result of a number of differences: between the practices and experiences of the design collaborators; between the conceptualisation of costume as static and a need for something new, yet relevant to the themes of emotion; and between the designers’ intentions and expectations of how a garment might be used, and the dancers’ response to the garments. Outcomes are discussed as moments in a complex and ongoing process, when meanings temporarily coalesce, only to be opened up again. Such a conceptualisation of design has major implications for how we think about methodology, evaluation, material and expertise.