This command is used to construct a four-node 3D acoustic viscous boundary quad element object based on a bilinear isoparametric formulation.
.. function:: element('AV3D4', eleTag, *eleNodes, matTag)
:noindex:
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``eleTag`` |int| unique element object tag
``eleNodes`` |listi| 4 end nodes
``matTag`` |int| Material Tag of previously defined nD material
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.. seealso:: `Notes <http://opensees.berkeley.edu/wiki/index.php/AV3D4>`_