Rapid-Mix’s goal is to develop new modes of musical interaction by including multimodal data connected to movement and the body. From a methodology point of view, the project is based on user-centric evaluations and on the quick development of prototypes. Advanced techniques for signal analysis and automatic learning are also used. The transfer of these technologies to small business taking part in the project is an important aspect of the project. In this project, IRCAM is responsible for the development of application prototypes (agile prototyping) in addition to its implication in the other aspects of the project.