Lp Centroidal Voronoi Tesselation and its applications

International audienceThis paper introduces Lp -Centroidal Voronoi Tessellation (Lp -CVT), a generalization of CVT that minimizes a higher-order moment of the coordinates on the Voronoi cells. This generalization allows for aligning the axes of the Voronoi cells with a predefined background tensor field (anisotropy). Lp -CVT is computed by a quasi-Newton optimization framework, based on closed-form derivations of the objective function and its gradient. The derivations are given for both surface meshing (Ω is a triangulated mesh with per-facet anisotropy) and volume meshing (Ω is the interior of a closed triangulated mesh with a 3D anisotropy field). Applications to anisotropic, quad-dominant surface remeshing and to hex-dominant volume meshing are presented. Unlike previous work, Lp -CVT captures sharp features and intersections without requiring any pre-tagging

Quad-dominant mesh adaptation using specialized simplicial optimization

Summary. The proposed quad-dominant mesh adaptation algorithm is based on simplicial optimization. It is driven by an anisotropic Riemannian metric and uses specialized local operators formulated in terms of an L ∞ instead of the usual L2 distance. Furthermore, the physically-based vertex relocation operator includes an alignment force to explicitly minimize the angular deviation of selected edges from the local eigenvectors of the target metric. Sets of contiguous edges can then be effectively interpreted as active tensor lines. Those lines are not only packed but also simultaneous networked together to form a layered rectangular simplicial mesh that requires little postprocessing to form a cubical-dominant one. Almost all-cubical meshes are possible if the target metric is compatible with such a decomposition and, although presently only two-dimensional tests were performed, a three-dimensional extension is feasible. Key words: Quad-dominant, mesh adaptation, anisotropic Riemannian metric.