6. Mesh module

Gmsh's mesh module regroups several 1D, 2D and 3D meshing algorithms, all producing grids conforming in the sense of finite elements (see section Mesh: finite element mesh generation):

• The 2D unstructured algorithms generate triangles or both triangles and quadrangles (when Recombine Surface is used: see Miscellaneous). The 3D unstructured algorithms generate tetrahedra.
• The 2D structured algorithms (transfinite and extrusion) generate triangles by default, but quadrangles can be obtained by using the Recombine commands (see Structured grids, and Miscellaneous). The 3D structured algorithms generate tetrahedra, hexahedra, prisms and pyramids, depending on the type of the surface meshes they are based on.

All meshes can be subdivided to generate fully quadrangular or fully hexahedral meshes with the Mesh.SubdivisionAlgorihm option (see section Mesh options list). However, beware that the quality of subdivided elements initially generated with an unstructured algorithm can be quite poor.