International audienceThe domain of Mixed Reality systems is currently making decisive advances on a daily basis. However, the knowledge and know-how of HCI scientists and interaction engineers, used in the design of such systems, is not well understood. This paper addresses this issue by proposing a software engineering method that couples a process for designing Mixed Reality interaction with a process for developing the functional core. Our development method features a Y-shaped development cycle that separates the description of functional requirements and their analysis from the study of technical requirements of the application. These sub-processes produce Business Objects and Interactional Objects, which are connected to produce a complete Mixed Reality system. The whole process is presented via a case study, with a particular emphasis on the design of the interactive solution
