# Complexity of the Delaunay triangulation of points on polyhedral surfaces

1 PRISME - Geometry, Algorithms and Robotics
CRISAM - Inria Sophia Antipolis - Méditerranée
Abstract : It is well known that the complexity of the Delaunay triangulation of $n$ points in $R ^d$, i.e. the number of its simplices, can be $\Omega (n^\lceil \frac{d{2}\rceil })$. In particular, in $R ^3$, the number of tetrahedra can be quadratic. Differently, if the points are uniformly distributed in a cube or a ball, the expected complexity of the Delaunay triangulation is only linear. The case of points distributed on a surface is of great practical importance in reverse engineering since most surface reconstruction algorithms first construct the Delaunay triangulation of a set of points measured on a surface. In this paper, we bound the complexity of the Delaunay triangulation of points distributed on the boundary of a given polyhedron. Under a mild uniform sampling condition, we provide deterministic asymptotic bounds on the complexity of the 3D Delaunay triangula- tion of the points when the sampling density increases. More precisely, we show that the complexity is $O(n^1.8)$ for general polyhedral surfaces and $O(n\sqrtn)$ for convex polyhedral surfaces. Our proof uses a geometric result of independent interest that states that the medial axis of a surface is well approximated by a subset of the Voronoi vertices of the sample points. The proof extends easily to higher dimensions, leading to the first non trivial bounds for the problem when $d>3$.
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https://hal.inria.fr/inria-00072355
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Submitted on : Tuesday, May 23, 2006 - 8:30:48 PM
Last modification on : Monday, November 16, 2020 - 2:10:03 PM
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### Identifiers

• HAL Id : inria-00072355, version 1

### Citation

Dominique Attali, Jean-Daniel Boissonnat. Complexity of the Delaunay triangulation of points on polyhedral surfaces. RR-4232, INRIA. 2001. ⟨inria-00072355⟩

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