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salome-med  6.5.0
Meshes in MEDCoupling

Common concept shared by all type of Meshes

A mesh has a the following properties :

In MEDCoupling library there is no presence of faces nor edges.

As a mesh has one dimension and only once, that is to say every cells in mesh have the same dimension called MeshDimension.

That is to say the MEDMEM vocabulary of faces and edges do not exist anymore here in MEDCoupling.

For exemple a mesh with a meshDimension equal to 1, have cells of type NORM_SEG2. An another exemple, a mesh with a meshDimension equal to 2, have cells of type NORM_TRI3 and NORM_POLYGON for example.

The class that incarnates the concept described above is : ParaMEDMEM.MEDCouplingMesh.

Unstructured meshes

An unstructured mesh is defined by :

As unstructured mesh is dynamically defined enough, this struture is used by MEDCoupling to instanciate degenerated meshes as :

The norm used for cells connectivity of different types, is the same as specified in MED file except that connectivities are in represented in C format and not in FORTRAN format !

The class in charge to dealt with the described concept is ParaMEDMEM::MEDCouplingUMesh. This class inherits from PointSet abstract meshes.


This is a non instanciable class that deals with set of points without any connectivity aspect.

The class that incarnates this concept in MEDCoupling is : ParaMEDMEM.MEDCouplingPointSet.

This class is in charge to perform whole or part of algorithms of its subclasses (MEDCouplingUMesh and MEDCouplingUMeshDesc) for factorization reasons.

Some of most important implemented methods are :

Cartesian Mesh

A cartesian mesh is a mesh that represents structured mesh whose nodes are arranged along axes of trihedron. To instanciate an object of this type, only n arrays are needed. In this type of mesh space dimension and mesh dimension are equals and the value is n. The n arrays will have only one component and the values contained in these arrays will be ascendantly sorted.

The class that incarnates this concept in MEDCoupling is : ParaMEDMEM.MEDCouplingCMesh.

Extruded Mesh

An extruded mesh is a mesh also called 2.5 D. It a convolution of 2D unstructured mesh with 1D unstructured mesh. The problem is that this type of mesh is not managed by any file format that's why to build an instance of this mesh you need 3D unstructured mesh and a 2D unstructured mesh lying on the same coordinates. The advantage of this structure is that the interpolation time is optimized.

The class that incarnates this concept in MEDCoupling is : ParaMEDMEM.MEDCouplingExtrudedMesh.