A topological hierarchy-sorting algorithm for layered manufacturing

This paper proposes an algorithm that constructs the topological hierarchy relationship of complex slice contours for layered manufacturing (LM). It facilitates toolpath generation for fabrication of multi-material parts and virtual simulation for defect quantification and process optimization of LM. The algorithm consists of two main modules, namely the hierarchy-sorting module and contour-sequencing module. The hierarchy-sorting module builds a parent-and-child list that defines the containment relationship of the slice contours, while the contour-sequencing module arranges the slice contours in an appropriate sequence based on the user's requirements. Topological hierarchy relationship facilitates toolpath planning for multi-material LM and also alleviates some major graphics problems in the virtual simulation of LM.