3D Dynamics is an add-on module to PLAXIS 3D. Soil and structures are often not only subjected to static loads due to construction in and on the ground surface but also to dynamic loads. When loads are powerful, like for example earthquakes, they may cause severe damages. Vibrations may occur either man-made or natural. In urban areas, vibrations can be generated due to pile driving, vehicle movement, heavy machinery or train travel. The source of natural vibrations in the subsoil is earthquakes. With the Dynamics module PLAXIS can analyse the effects of vibrations in the soil.