Abstract: In consideration of the couple of requirements including user-friendliness and effectiveness inmodel segmentation, we propose a novel algorithm to compute geodesic loops based on the intrinsic relationshipbetween geodesic loops and geodesic Morse-Smale saddle points. First, we use the Fast MarchingMethod to compute a geodesic distance filed rooted at a given point on the surface. Then we backtrack ageodesic loop for each Morse-Smale saddle point. Finally, we provide two ways for loop selection. One is toselect the geodesic loop that best matches the input stroke. The other is to automatically select the one thataligns concave feature lines. Extensive experimental results show that our algorithm is efficient and effective.