A mesh is a collection of primitive shapes (e.g. edges and vertexes) that represent the geometry of a scene object. There are two principal kinds of meshes: triangular meshes (Mesh) and polygon meshes (MNMesh). The triangular mesh is represented in the pipeline by a TriObject object and a polygon mesh is represented in the pipeline by a PolyObject.
The triangle mesh is a vertex based representation, and the polygon mesh is a winged edge topological model.
Patch meshes (PatchMesh) are covered in the section on Patches and Faces.