Computer-Aided Design (CAD) has been one of the focal research areas in advancing design automation for many years. The main areas of interest are processes that are required to design individual parts, to simulate their behavior and to inspect them. Assembly, which currently addresses the whole product, is, by comparison, much less studied and by far one of the least understood processes in design, knowing that almost all the CAD software are part-oriented. In order to offer a tool for the product model analysis this research focuses on Assembly/Disassembly (A/D) simulation, a simulation framework being proposed. A/D simulations can be performed either from an automated or interactive point of view using standard computer equipment or through immersive and real-time simulation schemes so the proposed framework is based on a new simulation preparation process allowing addressing up to two types of shape representations (B-Rep NURBS and polyhedrons). This software environment can assist designers to achieve a satisfactory assembly analysis rapidly and can reduce the lead-time of product development. Further consequences of the present work is its ability to produce models and treatments that improve integration of assembly models in immersive environments taking into account of the haptic and visual models needed. More, a specific operator, generating kinematic constraints in the neighborhood of contact configurations, is proposed for determining at each moment the valid movements between components. Thus, the complexity of the collision detection algorithms in the real time simulation environments is decreased. The operator is based on a mathematical model and on a geometric representation which offer the possibility to describe all valid combinations for the mounting or dismounting phases of a mechanical product