Question: at what elevation does the jet land farthest, with and without air drag? Without drag it is the textbook 45 degrees (lower when the nozzle is above ground); drag shifts the optimum and cuts the reach. The instant sweep integrates the trajectory; the 3D run steps the real nozzle through the angles and measures where the water lands.
Press a button. The current nozzle, pattern, pressure and ground height are used.