But === Define the geometry of the shock locations of a wire structure. These locations are defined in a plane perpendicular to the structure modelled by beams POU_D_T and POU_D_E. It is then used by DYNA_TRAN_MODAL [:external:ref:`U4.53.21 `] to study the response of a structure whose movements are limited by the presence of this obstacle. It is also possible to define the initial section of a structure whose gradual wear and tear will be studied. In the latter case, the concept will be used by MODI_OBSTACLE [:external:ref:`U4.44.22 `]. Produces a table_function concept.