2. GMSH entities and Aster groups

The GMSH modeler manipulates points, lines, surfaces, or volumes as geometric entities (not meshed). The GMSH mesh is built by meshing the lines, the surfaces and the volumes supported on them in this order.

In general, parts of the mesh are manipulated to apply material properties, boundary conditions, or loads. To access these subparts of the mesh, it is necessary to define « physical » ones in GMSH. A « physical » is composed of one or more geometric entities. The GMSH -Aster interface produces a group of elements for each « physical »: if the « physical 21 » consists of two volumes, the mesh group \(\mathit{GM21}\) contains the cells of these two volumes.

Note:

In GMSH, the entities constituting a « physical » are visualized by the Tools/Visibility menu and by selecting the number. You can then use the command DEFI_GROUP in Aster*to manipulate a more explicit group of elements name.*

Attention:

You should not create « physicals » combining other « physicals », as this would lead to the production of double meshes.

The number of « physicals » must be less than 1000000.