.. _V1.01.266:

**v1.01.266** ZZZZ266 - Validating the COOR_ELGA option from CALC_CHAM_ELEM
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**Summary:**

This test validates in :math:`\mathrm{2D}` and :math:`\mathrm{3D}` the calculation of the coordinates of the Gauss point using the command CALC_CHAM_ELEM.

Modeling A:

The principle is to read the mesh with command LIRE_MAILLAGE, assign a model using command AFFE_MODELE and calculate the coordinates of the Gauss point using option COOR_ELGA of command CALC_CHAM_ELEM. There is therefore no uncertainty about the results to be obtained:


* For a discrete type "POI1" the Gauss point is at the same position as the node.


* For a discrete type "SEG2" the Gauss point is in the middle of the segment.

Modeling B:

It is the same approach but for different models:


* For elements with plane deformations.


* For elements with plane constraints.


* For edge elements in three-dimensional modeling (faces and segments).


* For elements with 2D modeling_ FLUIDE (U_P and U_P_ PHI)

This documentation is deliberately brief.