Robust Engineering Design and Simulation with Tolerances 3 Concept

The use of solid geometric models and computer-aided design (CAD) systems is central to contemporary engineering design and simulation. For this engineering process to be robust, it is minimally necessary to have semantically consistent data exchange of solid models between diierent CAD systems. These solid models are assumed to be elements of the Boolean algebra of regular closed sets. In each CAD system, tolerance values are assigned to solid models as upper bounds for the approximations made within the underlying geometry creation algorithms. Such tolerances bound how much a particular model may deviate from the regular closed set assumption. The presence of tolerance values poses challenges for modern exchange methods, such as the STEP standard, even as very high reliability with STEP is being reported in various industrial domains. To further explore the role of tolerances within data exchange, we created a prototype to measure geometric accuracy of surface intersections on STEP models. That work led to our speciication of necessary conditions for any component-based software architecture to support the engineering design and simulation process. These speciication requirements are consistent with our proposed deenition of robustness as encompassing both model creation and usability. Context for our recommendations is provided by an economic justiication for the need for fully robust engineering design and simulation.