In Simulink^®, simulation pacing enables you to slow down a simulation to understand and observe the system's behavior. Visualizing simulations at a slower rate makes it easier to understand underlying system design, identify design issues, and demonstrate near real-time behavior. You can view the results and inspect your system while the simulation is in progress. Slow down animations in scopes to observe how and when the system changes state. 

Simulation pacing is useful in scenarios where one simulation-second is completed in a few wall clock time milliseconds. You can also manually interact with the model while it is running at a slower rate, which can help you to explore how your changes affect the simulation behavior. Note that the simulation will run at an approximation of the specified pace.