The fast development of technology and the time-to-market constraints need well-adapted technical support and development processes to ease design space exploration and the reduction of the productivity gap. Model Based Engineering (MBE) overcomes the increasing complexity of system being highly heterogeneous and integrating concurrent sub-systems. Elsewhere, Models of Computation (MoC) help enforcing MBE with aspects related to the execution semantics of models. In a previous paper, we introduced a language called Cometa providing more expressiveness for these aspects. It allows the capture and analysis of several MoCs at high level of abstraction, highlighting communication and synchronization among parts of a heterogeneous system. The language was tooled in Rhapsody and tested on an industrial case. In this paper, we present the key concepts of the Cometa language and the tooling experiments of Cometa in an open source environment. The objective of this approach is being able to model heterogeneous systems, but also to broaden the scope of the language tooling, by taking benefits from an open source environment.