Dropping a real-world robot off of a table or down stairs can cost a project millions of dollars and several months of repair time.  Any change in controlling software for automation infrastructure runs the risk of incompatibilities, wasted materials, or even damage.  One way to protect your project from these effects is to test your new software using simulation in the place of your expensive and vulnerable hardware.  Simulation offers opportunities for testing and precisely reproducing special conditions, emergencies, and faults that are unparalleled in the real world.  One can slow down or stop time, alter the environment or state of the robot, view from multiple camera angles at once, and turn on or off logging with the press of a button.  And while the number of physical robots or assembly lines at a site may be limited, additional simulated robots or assembly lines can be added with little or no cost.  (Depicted is a simple pendulum.)