At this point, the Toolbar buttons that we are most interested in are those in the Simulator control pane.

As you may have guessed, the simulator operates in both an "on" and an "off" state.

In the "off" state, we can freely move and rotate objects in the model space.

In the "on" state, the simulators’ physics engine is activated, making it much more difficult to manipulate objects since we must now overcome physical forces such as gravity.