Global performance analysis for an offshore wind turbine is primarily conducted to calculate the global responses including displacements, motions, and loads that can be used for the design and design evaluation of the offshore wind turbine and its subsystems and components. The subsystems of an offshore wind turbine typically include the rotor-nacelle assembly (RNA), support structure, and if deemed relevant, power cables. For a bottom-founded offshore wind turbine, the support structure comprises the tower, substructure, and foundation. For a floating offshore wind turbine, the support structure comprises the tower, floating substructure, and station keeping system. The complexity and fidelity of these subsystems in the global performance analysis model may vary at distinctive design stages. In the design process of an offshore wind turbine, wind turbine manufacturers design the wind turbine generator (WTG) including the RNA and the tower.