Efficiently computing geodesic offsets on triangle meshes by the extended Xin-Wang algorithm

  • Authors:
  • Shi-Qing Xin;Xiang Ying;Ying He

  • Affiliations:
  • -;-;-

  • Venue:
  • Computer-Aided Design
  • Year:
  • 2011

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Abstract

Geodesic offset curves are important for many industrial applications, such as solid modeling, robot-path planning, the generation of tool paths for NC machining, etc. Although the offset problem is well studied in classical differential geometry and computer-aided design, where the underlying surface is sufficiently smooth, very few algorithms are available for computing geodesic offsets on discrete representation, in which the input is typically a polyline curve restricted on a piecewise linear mesh. In this paper, we propose an efficient and exact algorithm to compute the geodesic offsets on triangle meshes by extending the Xin-Wang algorithm of discrete geodesics. We define a new data structure called parallel-source windows, and extend both the ''one angle one split'' and the filtering theorem to maintain the window tree. Similar to the original Xin-Wang algorithm, our extended algorithm has an O(n) space complexity and an O(n^2logn) asymptotic time complexity, where n is the number of vertices on the input mesh. We tested our algorithm on numerous real-world models and showed that our algorithm is exact, efficient and robust, and can be applied to large scale models with complicated geometry and topology.