But
===

This macro command allows a fast and efficient post-processing calculation to determine the floor spectra of any building after dynamic seismic analysis.

For example, it can be used after a transient dynamic calculation of a building during the earthquake, where the connections between the ground and the base in mono-support or multi-support are simulated by ground stiffness (DYNA_TRAN_MODAL [:external:ref:`U4.53.21 <U4.53.21>`], dynamic transient calculation on a reduced modal basis, calculated as a relative coordinate system, calculated as a relative coordinate system, product concept: resu_gene) or after calculations resulting from the *Code_Aster* - *Promiss3D* coupling (CALC_MISS [:external:ref:`U7.03.12 <U7.03.12>`]), concept product: tran_gene or harm_gene) or even following a non-linear transient dynamic resolution (DYNA_NON_LINE, evol_noli concept, and on the observation table resulting from a calculation of this type).

This macro-command executes in succession:


1.
    * the extraction of the relative acceleration in one or more nodes of the mesh in the result concept (RECU_FONCTION [:external:ref:`U4.32.03 <U4.32.03>`]);


    * the combination with ground acceleration to obtain absolute acceleration (CALC_FONCTION [:ref:`U4.32.04 <U4.32.04>`]);


    * calculating the acceleration response spectrum with several damping coefficients (CALC_FONCTION [:ref:`U4.32.04 <U4.32.04>`]);


    * the envelope function of the relative displacement or acceleration corresponding to a given floor.


    * the printing of the spectra enveloped by floor and by direction.


    * the creation of a table for spectra are included in/envelope of all floors.

For practical examples of implementation, the reader can refer to test cases SDNL131 (post-processing of a pipe analysis), SDNV112 (multi-support type seismic building) or tests SDLX101, SDLX101, MISS01, MISS05 with coupling calculation *Code_Aster* - *Miss3D*.

The macro command produces a table_sdaster concept.