Building on the concept “prototypes that filter the design space,” we establish how other kinds of design artifacts and activities (e.g., sketching, tests, concept posters, metaphors, design tools) are equally critical in filtering the design space. We also suggest a parallel term, “informing the design space,” to define how design artifacts and activities expand the design space. We focus on a 16-month, full-scale media architecture design project and zero in on seven of its component events, and use design-space schemas to shed light on the dynamics of the design space with respect to informing and filtering the design space. Our concluding contribution is to propose design-space thinking as a sub-discipline of design research. We argue that this research perspective serves to address the creative aspects of the design process, the generative potential of design-space thinking, and the tools that support design-space thinking and research.