GIBI and Aster mesh entities
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The GIBI mesher manipulates typed and named objects (See GIBI usage doc).

The types used are:


* integer, real, text,... constants


* the POINTS,


* the MAILLAGES (mesh set).

The effect of command PRE_GIBI is:


*to write the points (GIBI) in the form of nodes (*Aster*): the names of the*Aster* nodes are of the form: :math:`{N}_{i}` where :math:`i` is the number GIBI of the corresponding point,


*to write the meshes (*Aster*) contained in the meshes (GIBI): the names of the*Aster* cells are of the form: :math:`{M}_{j}` where :math:`j` is the order number of the mesh GIBI in the result file GIBI,


*to write GROUP_MA (*Aster*) corresponding to meshes (GIBI) and of the same names,

**Note:**

*The mesh groups only contain the cells that actually define mesh GIBI. They do not contain the meshes of the objects referenced in this mesh (the edges for example) .*


*to write GROUP_NO (*Aster*) reduced to a single node and whose names are the names of the points in GIBI.

Note that PRE_GIBI does not generate a GROUP_NO containing multiple nodes. This would sometimes be very useful to impose boundary conditions on all the nodes on one side. To do this, the user has the DEFI_GROUP command in Aster, which allows you to create groups of nodes from groups of meshes.

The CREA_GROUP_NO keyword of the DEFI_GROUP [:external:ref:`U4.22.01 <U4.22.01>`] operator makes it possible to get around this obstacle.