We present a software tool, the Rodin tool, for formal modelling in Event-B. Event-B is a notation and method developed from the B-Method and is intended to be used with an incremental style of modelling. The idea of incremental modelling has been taken from programming: modern programming languages come with integrated development environments that make it easy to modify and improve programs. The Rodin tool provides such an environment for Event-B.
The two main characteristics of the Rodin tool are its ease of use and its extensibility. The tool focuses on modelling. It is easy to modify models and try out variations of a model. The tool can also be extended easily. This will make it possible to adapt the tool specific needs. So the tool can be adapted to fit into existing development processes instead demanding the opposite. We believe that these two characteristics are major points for industrial uptake.