AbstractResearch developments leading to implementation of an intelligent software environment supporting system design and simulation are presented. Knowledge-based system design and multifaceted simulation methodologies are a foundation for the system realization. The paper describes the major theoretical concepts and processes employed to develop and simulate design models. The environment implementing these concepts and methods consists of two basic components: one serves as a front end supporting the model construction processes; the other is an object-oriented, discrete-event simulator supporting evaluation of hierarchical, multi-component models. Current state of the system implementation and future work are discussed.