Comparison of the solvent excluded surface (Left) of protein 1PPL and surface generated by the Laplace-Beltrami flow with V1 = 0 (Right). The latter is free from geometric singularity. In the generation of 1PPL MMS, an outer layer of 1.7Å is used to immerse the protein in solvent. The comptational domain for protein 1PPL is [−14.7, 57.8]*[−16.7,41.3]*[−8.2,39.8]. We set the grid size to be 0.5 Å, and 100 iterations are carried out.