MeshLab is an open source, portable, and extensible system for the processing and editing of unstructured 3D triangular meshes.
The system is aimed to help the processing of the typical not-so-small unstructured models arising in 3D scanning, providing a set of tools for editing, cleaning, healing, inspecting, rendering and converting this kind of meshes.

Main features:

- Interactive selection and deletion of portion of the mesh. Even for large models.
- Painting interface for selecting, smoothing and coloring meshes.
- Input/output in many formats:

--- import:PLY, STL, OFF, OBJ, 3DS, COLLADA, PTX, V3D, PTS, APTS, XYZ, GTS, TRI, ASC, X3D, X3DV, VRML, ALN
--- export:PLY, STL, OFF, OBJ, 3DS, COLLADA, VRML, DXF, GTS, U3D, IDTF, X3D
--- Point Clouds support. Now 3D files that are composed only by points are well supported in PLY and OBJ format.
--- U3D support; MeshLab is the first open source tool to provide direct conversion of 3D meshes into the U3D format. Now you can create pdf, like this with 3D objects with just MeshLab and LaTeX.

- Mesh Cleaning Filters:

--- removal of duplicated, unreferenced vertices, null faces
--- removal of small isolated components
--- coherent normal unification and flipping
--- erasing of non manifold faces
--- automatic filling of holes

- Remeshing filters:

--- High quality edge collapse simplification (even with texture coords preservation)
--- Surface reconstruction from points (a ball pivoting variant, marching cubes and poisson's reconstruction)
--- Subdivision surfaces (loop and butterfly)
--- Feature preserving smoothing and fairing filters
--- Holes filling