The HI-maude tool. In complex hybrid systems, different components may influence each others’ continuous behaviors. HI-Maude is a rewriting-logic-based tool that supports an object-oriented modeling methodology in which it is sufficient to specify the continuous dynamics of single (physical component and physical interaction) objects in such interacting hybrid systems. HI-Maude supports simulation and model checking for a number of numerical approximations of the continuous behaviors, based on adaptations of the Euler and the Runga-Kutta methods.