  A pair of pants is a genus zero orientable surface with three boundary
components. A pants decomposition of a surface is a finite collection of
unordered pairwise disjoint simple closed curves embedded in the surface that
decompose the surface into pants. In this paper we present two Morse theory
based algorithms for pants decomposition of a surface mesh. Both algorithms
operates on a choice of an appropriate Morse function on the surface. The first
algorithm uses this Morse function to identify handles that are glued
systematically to obtain a pant decomposition. The second algorithm uses the
Reeb graph of the Morse function to obtain a pant decomposition. Both
algorithms work for surfaces with or without boundaries. Our preliminary
implementation of the two algorithms shows that both algorithms run in much
less time than an existing state-of-the-art method, and the Reeb graph based
algorithm achieves the best time efficiency. Finally, we demonstrate the
robustness of our algorithms against noise.
