Specify a Solver Choose a solver and define solver parameters for your simulation requirements. For information about Solvers, see the chapter, Altair Activate Hybrid Simulator and Interface with Numerical Solvers in the Extended Definitions. On the ribbon, hover over the Simulate tool group, and click the simulation parameters tool: On the Simulation Parameters dialog that appears, select the Solvers tab and define the options in the tab as required for your simulation. Tip: You can monitor the solver step-size with the SimulatorInfo block found in the Activate > ActivationOperations palette.