BIM as a new planning tool in construction facilitates the generation of threedimensional finite element models of buildings. Hence, 3D FE models are available more and more also for earthquake analysis. The paper shows how dynamic Soil-Foundation-Structure-Interaction (SFSI) can be included in the analyses of 3D models in engineering practice with commercial FE software. Flexibility of the foundation slab is taken into account. A model of coupled distributed (Winkler) springs and dampers based on half-space solutions of impedance functions is suggested which consistently represents the rocking and vertical motions of the foundation. The results compare well with a more rigorous but numerically efficient SBFEM (Scaled Boundary Finite Element Method) analysis for a 3-storey building on a half-space.