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Title Terminal Triangles Centroid Algorithms for Quality Delaunay Triangulation
Authors María Cecilia Rivara, Javier Diaz
Publication date 2020
Abstract Two Lepp algorithms for quality Delaunay triangulation are discussed. Firstly a terminal triangles
centroid Delaunay algorithm is studied. For each bad quality triangle t, the algorithm uses the longest
edge propagating path (Lepp(t)) to find a couple of Delaunay terminal triangles (with largest angles
less than or equal to 120 degrees) sharing a common longest (terminal) edge. Then the centroid of the
terminal quadrilateral is Delaunay inserted in the mesh. Insertion of the midpoints of some constrained
edges are also performed to assure convergence close to the constrained edges. We prove algorithm
termination and that a graded, optimal size, 30 degrees triangulation is obtained, for any planar straight
line graph (PSLG) geometry with constrained angles greater than or equal to 30 degrees. We also prove
that the size of the final triangulation is optimal and that this size is independent of the processing
order of the bad triangles in the mesh. Next, by introducing the concept of non-improvable triangles
(with constrained angle < 30 degrees), we generalize the algorithm to deal with PSLG geometries with
N small constrained angles. Thus given a triangle size parameter delta for non-improvable triangles, the
generalized algorithm constructs a quality triangulation with non constrained angles ≥ 30 degrees and
at most N non-improvable triangles of size delta (longest edge ≤ delta). In practice the algorithms behave as
predicted by the theory.
Pages article 102870
Volume 125
Journal name Computer-Aided Design
Publisher Elsevier Science (Amsterdam, The Netherlands)