This dissertation presents assessments, metrics, and techniques for generating hexahedral finite elements on Computer-Aided Design (CAD) models. Three specific areas are addressed. (1) Meshing complexity. The new research field for determining the difficulty encountered by users during hexahedral mesh generation is proposed. A metric is introduced to approximate the meshing complexity of CAD models. New methods have been developed to detect features that cause meshing difficulty. A meshing complexly study that includes a test suite of real CAD parts, illustrates the applicability of the proposed meshing complexity metric. (2) Imprint and merge. A geometrically tolerant method for imprinting and merging CAD models has been developed. Imprinting and merging is a key capability for generating conforming meshes on assemblies of CAD parts. Boundary imprinting discretizes the face boundaries of CAD parts to perform geometrically tolerant intersections to compute feasible connections between adjacent assembly parts. The ability to do this tolerantly avoids the creation of small features in the overall assembly, thus decreasing the meshing complexity of the system. (3) CCSweep, automatic decomposition of multi-sweep volumes. The CCSweep algorithm automatically decomposes many-to-many sweepable volumes into multiple volumes that can be automatically meshed using existing techniques. CCSweep cuts through the volume to intersect the source and target faces in order to make hexahedral mesh generation automatic and reducing the meshing complexity for a large class of common CAD geometries.
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