The rapid advance of hardware and software technologies has led to a continuous increment in the complexity of real-time systems. On the other side, requirements of these systems are increasingly stringent: more functionality with less resources, and in less time. The main weapons to manage the development of RTS are methodologies based on risks reduction and life cycle's steps integration. This article presents a toolset that supports heterogeneous prototyping. This technique relies upon the development of evolutionary models of the system, whose parts are built at different speeds, the higher risk part being developed first. The toolset allows the execution and validation of a global model of the system under development, in which some parts are still at the specification or design stage while others have been already fully implemented. The internal architecture of the tools is shown, and their use for validation through animation of heterogeneous prototypes is pointed out. All concepts are applied to a small example.