Decision criteria for computer-aided parting surface design
Computer-Aided Design
Moldable and castable polygons
Computational Geometry: Theory and Applications
Computational geometry: algorithms and applications
Computational geometry: algorithms and applications
Representations for Rigid Solids: Theory, Methods, and Systems
ACM Computing Surveys (CSUR)
Finding feasible mold parting directions using graphics hardware
Computer-Aided Design
Characterization of polyhedron monotonicity
Computer-Aided Design
Generating smooth parting lines for mold design for meshes
Proceedings of the 2007 ACM symposium on Solid and physical modeling
Computer-Aided Design
New methodology for demoldability analysis based on volume discretization algorithms
Computer-Aided Design
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For molding and casting processes, geometries that have undercut-free parting directions (UFPDs) are preferred for manufacturing. Identifying all UFPDs for arbitrary geometries at interactive speeds remains an open problem, however; for polyhedral parts with n vertices, existing algorithms take at least O(n4) time. In this paper, we introduce a new algorithm to calculate all the UFPDs for extrusions, an important class of geometry for manufacturing in its own right and a basic geometric building block in solid modeling systems. The algorithm is based on analyzing the 2D generator profile for the extrusion, building on our previous results for 2D undercut analysis of polygons. The running time is O(n2logn) to find the exact set of UFPDs or O(n) to find a slightly conservative superset of the UFPDs, where n is the geometric complexity of the 2D generator profile. Using this approach, the set of possible UFPDs for a part containing multiple extruded features can be reduced based upon an analysis of each such feature, efficiently identifying many parts that have no UFPDs and reducing the search time for complete algorithms that find all UFPDs.