Mesh file structure
================================

The *Aster* mesh file is read from the first line to the first occurrence of a line beginning with the word **FIN** **. This keyword is mandatory.

The *Aster* mesh file consists of a succession of independent mesh sub-files.


+-------------------------------------------------------------------------------------------------------------------------------------+
|                                                                                                                                     |
+ .. image:: images/1000000000000124000002006F3F93AA5FEF6722.png                                                                      +
|    :width: 1.4472in                                                                                                                 |
+    :height: 2.8827in                                                                                                                +
|                                                                                                                                     |
+ **FIN**                                                                                                                             +
|                                                                                                                                     |
+-------------------------------------------------------------------------------------------------------------------------------------+


The **Aster mesh** file is a file with format, in the sense of FORTRAN:


* line length is limited to 80 characters (any information starting from column 81 is simply ignored);


* the white character '' and the comma ',' are the only separators recognized,


* the% character is a reserved character to indicate the beginning, until the end of the line, of a comment,


* numerical data is interpreted in free format:


.. code-block:: text

    1 = 1. = 1.0 = 1.E+0 = .1E1 = 10.D-1

The **mesh** file must contain at least:


* a sub-file of node coordinates COOR_2D or COOR_3D, defined by 2 or 3 real numbers in a single orthonormal coordinate system.


* one sub-file per type of mesh used.

It may also contain, and this is recommended, a sub-file TITRE. It is almost essential to define, at the time of meshing, mesh group subfiles GROUP_MA and node group subfiles GROUP_NO **.**

Note that the assignment of a finite element type can only be done on a mesh (or exceptionally on a node for discrete elements) described in the mesh file. Loads or boundary conditions are affected on meshes or on nodes as appropriate.