Unformatted text preview: ification phases Another result of mathematization in GPS project is the recognition that different geometrical models can be used to describe a mechanical product along its lifecycle and that relationships among the different models should be identified in order to assure a unique description of the part. In the GPS project there exist two different contexts: specification and verification. In the specification phase designers describe product shapes by means of nominal surfaces. In order to assure the product functionality, designers use a virtual defective model (the skin model), to establish the admissible limits on the variability of non-ideal surfaces in manufactured parts. In the verification phase, metrologists extract information from the manufactured parts in order to identify non-ideal surfaces, the physical alter-ego of the skin model, and to establish their congruence with the specifications imposed by geometrical tolerancing. The gap existing between the specification and verification phases is solved in the GPS project by means of duality principle: the sets of operations used in the specificati...
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- Spring '10
- The Land, ........., Computer-aided design, Joseph K. Davidson, M. GIORDANO