Abstract: A constrained boundary recovery algorithm for 3D unstructured meshes which combines vector boundary advancing triangulation method(VBATM) with Steiner point perturbation is presented.From conforming mesh,constrained edges and faces could be recovered by Steiner point perturbation and VBATM to reconstruct triangulation on constrained faces.The tetrahedral-eating method can be used to get rid of Steiner points as many as possible.Different from existing methods,the algorithm does not need edges/faces swapping(flip) method and side compress method.Convergence and stability of the method are theoretically studied.Numerical examples are provided to illustrate effectiveness of the method.

Key words: conforming mesh, constrained mesh, Steiner point perturbation, boundary recovery, VBATM