FLAC3D is the best solution to solve complex geotechnical problems for three-dimensional analyses of soil, rock, concrete, structural ground support, and groundwater flow. Options can be added to expand analyses (dynamic, creep, thermal, and IMASS) and to create user-defined constitutive models (UDMs). FLAC3D 9 has an improved user interface (UI) and new interactive tools to construct and interpret models easily. FLAC3D provides an incredibly accurate simulation of real-world geotechnical conditions for engineering applications, such as slope stability, underground excavation behavior, and earthquake simulations. Flexible commands and scripting allow for model parameterization, flexibility, customization, and automation.