For molding and casting processes, geometries that have undercut-free parting directions (UFPDs) are preferred for manufacturing. However, existing approaches either cannot identify all UFPDs or cannot run at interactive speeds (the best exhaustive algorithm, unimplemented, runs at O(n4) time theoretically). Our proposed feature-based approach avoids testing the whole Gaussian sphere of potential directions by first efficiently identify all UFPDs for individual features such as extruded and revolved features, thus significantly reducing test space and running time. In this paper, we describe a fast algorithm to find all UFPDs for solids of revolution. The algorithm is based on analyzing the constructing 2D generator profiles, building on our previous results for 2-moldability analysis of polygons. The running time is O(n), where n is the geometric complexity of the 2D generator profile. For parts containing multiple solids of revolution, the set of possible UFPDs can be significantly reduced based upon an analysis of each such feature, efficiently identifying many as non-2-moldable or reducing the search space for exhaustive algorithms that find all UFPDs.

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