Using a computational domain and a three-stage node location procedure for multi-sweeping algorithms

Abstract

The multi-sweeping method is one of the most used algorithms to generate hexahedral meshes for extrusion volumes. In this method the geometry is decomposed in sub-volumes by means of projecting nodes along the sweep direction and imprinting faces. Nevertheless, the quality of the final mesh is determined by the location of inner nodes created during the decomposition process and by the robustness of the imprinting process.In this work we present two original contributions to increase the quality of the decomposition process. On the one hand, to improve the robustness of the imprints we introduce the new concept of computational domain for extrusion geometries. Since the computational domain is a planar representation of the sweep levels, we improve several geometric operations involved in the imprinting process. On the other hand, we propose a three-stage procedure to improve the location of the inner nodes created during the decomposition process. First, inner nodes are projected towards source surfaces. Second, the nodes are projected back towards target surfaces. Third, the final position of inner nodes is computed as a weighted average of the projections from source and target surfaces.

Hex-Mesh Generation and Processing: a Survey

“…These methods often rely on specific rules to detect line and planar features, such as various angle thresholds, so that the 3D model can be decomposed into sub-volumes having the same sweeping direction. If the decomposition is successful, various node insertion tricks for the sweeping can be employed to ensure the high quality of the generated hex-mesh [Knupp 1998;Ruiz-Gironés et al 2011;Staten et al 1999]. There are also approaches that allow multiple sweeping directions by computing a hierarchical sub-geometry structure [Miyoshi and Blacker 2000].…”

Loopy Cuts: Surface-Field Aware Block Decomposition for Hex-Meshing

“…Surface-driven block-decomposition techniques use surface features to guide cutting surfaces. Cuts can be used to define both the primal [Blacker 1996;Liu and Gadh 1997;Miyoshi and Blacker 2000;Ruiz-Gironés et al 2011] or the dual structure [Gao et al 2018]. Dual methods hardly support feature alignment, because cuts do not directly produce mesh edges, and geometric snapping should be used in post processing to conform with the input features.…”

Simultaneous untangling and smoothing of quadrilateral and hexahedral meshes using an object-oriented framework

“…The last three examples are devoted to the optimization of hexahedral meshes for real-world geometries. Specifically, the third and four examples present an application to semi-structured hexahedral meshes for multi-sweeping [3,4,5,6] mechanical pieces. In the last example, we improve the quality of a unstructured hexahedral mesh generated using the receding front method [14].…”