Dear nThank you very much for answering. it is always highly appreciated. And best wishes for the new year n**********nIn the case of Impedance function, If we can extract reaction forces at each node or etc.. and the corresponding deformations (transnational and rotational, all together 6 ) at each frequency in complex form, we could calculate the impedance function. nFor the nodal reaction extraction, for eg. in WB it allows to locate the nodes by few options...May be i ll try to use what you suggest in one of my other questions (using ENFOX etc..) But i can remember i tried this once but was not successful, i ll give it a go again..nn Following are the names of two papers i found out about the procedurenANALYSIS OF THE IMPEDANCE FUNCTIONS USING 3D FINITE ELEMENT MODEL OF SUBSOIL, J. Králik *, P. Roško**, J. Králik, jr.*nCalculation of Dynamic Impedance of Foundations Using Finite Element Procedures , by C. Coronado and N. GidwaninThank younBest Regardsn