Model Driven Engineering (MDE) is a good candidate for scaling up complex systems thanks to the principle of separation of concerns. In HCI, models describe the UI at different levels of abstraction and are matched to each other with a variety of relationships. However, MDE puts HCI designers in front of a new problem which is mastering the complexity of many and possibly huge models. Parallel to this evolution, "Big Data" is an important research trend. It brings new perspectives to deal with "Big Models". The paper presents MoVi (Model Visualization), an interactive environment that bridges the gap between these two trends by processing models as data.