Version: 9.12.0

Meshes

Several types of meshes are available in MEDCoupling:

- Point set mesh (abstract, can not be instantiated)
- Unstructured meshes
- Cartesian meshes
- 3D Extruded meshes

A mesh has the following properties :

- a name (a string)
**a dimension (called mesh dimension) and only one**(it implies that**all**cells constituting mesh have the same dimension, e.g. no mix between a volumic cube and a flat triangle in the same mesh). This point matters as it differs from what the MED file format authorizes.- a space dimension (the space where the coordinates of the points are defined)
- a set of nodes
- a set of cells (whose vertices are in the node set above)

In MEDCoupling library there is no explicit notion of faces nor edges. All cells, be it in 3D, 2D or 1D is described by a set of point, or by a set of coordinates.

As said above, a mesh has only one dimension, which is often called the "mesh dimension". This notion is different from the "space dimension", corresponding to the dimension of the space where the nodes are defined.

For example a mesh with a mesh dimension equal to 1 can have **cells** of type NORM_SEG2 (simple segments). This mesh can however have a space dimension of 3, meaning that we describe a 3D polygonal line. Another example: a mesh with a mesh dimension equal to 2, can have **cells** of type NORM_TRI3 (triangles) and NORM_POLYGON (arbitrary 2D polygons) for example. It can still have a space dimension of 3, meaning that we describe a planar surface embedded in a 3D space.

The (abstract) class that covers the concept described above is MEDCoupling::MEDCouplingMesh.