Organizations are highly dependent on their software in carrying out their daily activities. Unfortunately, the repeated changes that are applied to these systems make their evolution difficult. This evolution may be necessary to maintain the software, replace or upgrade it. In the case of complex and poorly documented legacy systems, modernization is the only feasible solution to achieving the evolution goals. The OMG (Object Management Group) consortium created the Architecture-Driven Modernization (ADM) initiative to cope with the challenges of modernization. This initiative proposes, among other things, modernization through model-driven engineering (MDE). In this context, the modernization of a legacy system, not developed in an MDE environment, begins with its migration towards this type of environment. This migration raises the problem of finding the models necessary for the use of MDE representing this system.In this paper, we present a new bimodal approach to ADM modernization by enabling automatic and interactive modes to discover a view of the implementation platform of a legacy object-oriented system. Also, we present the key ideas of the algorithms behind this discovery process. Finally, we describe our prototype tool that implements our approach. This tool has been validated on several systems written in C# and Java languages.