Automatic decomposition of protrusion volumes on thin-shell models for hexahedral mesh generation

Hexahedral mesh generation of thin-shell models is frequently constrained by volume decomposition, which is tedious and time-consuming. The complex geometries of a thin-shell model make volume decomposition more challenging. Creating a hexahedral mesh can be simplified by splitting the thin-shell volume into two types of subvolumes, namely the main-shell and protrusions body. A set of shared surfaces between subvolumes of main-shell and protrusion feature in the decomposition process, called cap faces herein, are formed by considering the natural boundary face of each subvolume. A novel protrusion feature graph is proposed to facilitate cap face generation on the bottom area that forms an interconnected protrusion structure, and to assist in optimizing the number of cap faces. The split and merge strategy are employed to generate individual solid subvolumes for main-shell and protrusion. This automatic approach is implemented in a CAD platform, and the decomposed model is tested on a mesh generator. The decomposition results of several thin-shell models, along with the CPU time required, are presented to validate the feasibility of the proposed algorithm.