The MESH class is dedicated to the handling of unstructured meshes. Two classes derive from it : MESHING supplies functions for creating meshes from scratch (c.f. MESHING), while GRID gives specific constructors for creating structured meshes.
Underlying the unstructured meshes is the notion of connectivity. This section only covers meshes made out of standard elements, the MED_POLYGON
and MED_POLYHEDRA
case being detailed in section Polyhedra and polygons .
Nodal connectivity storage scheme
The cell types are ordered by their number of nodes.
As an example, let us consider a mesh made out of a linear triangle, two linear quadrangles and a quadratic triangle (c.f. figure fig_connectivity_example ).
Example for mesh connectivity
The type array writes : MED_TRIA3, MED_QUAD4, MED_TRIA6
The global numbering index is : 1,2,4,5 }. Its dimension is so that elements of type
are stored between element
and
(
).
The connectivity array writes : 1, 2, 3, 2, 4, 5, 3, 5, 6, 7, 8, 4, 6, 5, 10, 11, 9
The connectivity index array writes : 1, 4, 8, 12, 18
Its dimension is , in order to be able to write that nodes of element
are located in the connectivity array between
and
(
).\
The description of MESH methods is given by the following sections :