A mesh repair engine is configured to repair a hole in a three-dimensional (3D) model by (i) filling the hole with a rough mesh, (ii) refining the rough mesh, (iii) collapsing the refined mesh, (iv) refining the collapsed mesh, (v) flattening the refined, collapsed mesh, and then (vi) deforming the flattened mesh into a 3D surface that smoothly fills the hole in the 3D model. One advantage of the disclosed repair engine and associated hole repair technique is that the mesh repair engine is capable of generating polygons that fill regions of a 3D model that are not defined. Consequently, an end-user of the mesh repair tool is able to generate watertight 3D models from previously incomplete and non-watertight 3D models.