Tolerance analysis of mechanical assemblies requires the identification of locations of potential part interference, and determining whether the allowable geometric variation permitted by the part tolerances will cause part interference. Current commercial assembly modelers (and much of the classic work in assembly research [1-3]) require that the degrees of freedom between parts in an assembly be fully constrained prior to analysis. This method relies on the kinematics of the assembly contacts to determine whether the parts will assembly without interference. Our method — GapSpace — does not require these constraints in determining if interference-free assembly is possible [4]. Less restrictive, and thus less costly, tolerances can be used in assemblies where the specific relationships between surfaces is not predetermined. One difficulty we’ve had in implementing this GapSpace method is overcoming the constraints imposed by commercial modeling systems [5]. In this paper we report our success in implementing the GapSpace techniques in one such modeling system. Included in this system are additional user menus and interfaces which allow the identification of “fitting conditions” and analysis of the tolerances placed on the assembly components.

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