Efficient computation of a simplified medial axis

  • Authors:
  • Mark Foskey;Ming C. Lin;Dinesh Manocha

  • Affiliations:
  • University of North Carolina at Chapel Hill;University of North Carolina at Chapel Hill;University of North Carolina at Chapel Hill

  • Venue:
  • SM '03 Proceedings of the eighth ACM symposium on Solid modeling and applications
  • Year:
  • 2003

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Abstract

Applications of of the medial axis have been limited because of its instability and algebraic complexity. In this paper, we use a simplification of the medial axis, the θ-SMA, that is parameterized by a separation angle (θ) formed by the vectors connecting a point on the medial axis to the closest points on the boundary. We present a formal characterization of the degree of simplification of the θ-SMA as a function of θ, and we quantify the degree to which the simplified medial axis retains the features of the original polyhedron.We present a fast algorithm to compute an approximation of the θ-SMA. It is based on a spatial subdivision scheme, and uses fast computation of a distance field and its gradient using graphics hardware. The complexity of the algorithm varies based on the error threshold that is used, and is a linear function of the input size. We have applied this algorithm to approximate the SMA of models with tens or hundreds of thousands of triangles. Its running time varies from a few seconds, for a model consisting of hundreds of triangles, to minutes for highly complex models.