An important issue for communication processes in general, and for multimodal interaction in particular, is the information output arrangement and organization (multimodal fission). Considering information structure, intonation, and emphasis for the output by speech, considering moreover spatio-temporal coordination of pieces of information for visual (video, graphics, images, and texts) outputs, designing outputs for each kind of modality, and synchronizing the different outputs modalities is one of the most relevant challenges of the multimodal interaction design process; it is called fission. This challenge is becoming more and more important with the use of a lot of different interaction devices from laptop to mobile and smart-phones, in different contexts. This chapter provides some basic concepts involved in the fission processes design and describes some of the most relevant approaches discussed in the literature.