| Simulator Background Properties: To open the simulator background Properties Box, depress Select. Then double-click or control-click in a clear area of the simulation window. In the Properties Box, you can set a wide variety of properties. These properties are discussed in detail under the topic headings listed below. Table of Contents. Click on the topic of interest.
Reference System & Grid | Path Display | Time Parameters
Gravitatonal Potential Zero Level
Reference System & Grid Properties X enabled / Y enabled: These options control whether or not the X-axis and Y-axis are displayed. Default condition is to hide the axes. X grid enabled / Y grid enabled: These options control whether or not horizontal (X) and vertical (Y) grid lines are displayed. Default condition is to hide the grid lines. Horizontal / Vertical step: These properties set the size of the intervals on the X-axis and Y-axis. The step sizes are in terms of distance measures, such as meters (the default), rather than pixels. An axis interval is equal to two grid intervals.
The step sizes are also controlled by three hotspots located near the grid's origin. The scales controlled by the hotspots are indicated in the figure to the right. To change the X and Y scales, click-and-drag the hotspots. Changing step sizes using hotspots does not change the values in the background properties. The origin itself is a hotspot that you can click-and-drag from the lower left-hand corner to a new location. |
Return to Contents Path Display Properties Show path: This option enables the rendering of the path traveled by a body during Run mode (simulations). The simulator renders the path by drawing a representation (see next bullet) of the path at regular intervals. The path remains on display in Stop mode after the simulation concludes. Represent Path as: This option determines how the simulator represents the path. The choices are: dots of the same color as the body; pictures of the body; speed vectors that represent the body's speeds at the times the representations are drawn; and net force vectors that represent the net forces acting on the body at the times the representations are drawn. Display path, steps: This property determines how frequently the simulator draws a representation of the path. This property sets the number of "refresh steps" between renderings. Hence, the time interval between subsequent renderings of the path is the product of this property and the refresh time. Return to Contents Time Parameters Stop time, seconds: The duration of simulation runs (i.e., Run mode), provided that the Stop button is not pressed. The default duration is 10 seconds. The maximum duration is 60 seconds. Refresh time, ms: This property determines how often the simulator refreshes the simulation window during simulation runs (Run mode). The default refresh time is 100 ms or 0.1 sec. The minimum is 20 ms and the maximum is 200 ms. Low refresh times are more computationally intensive than high refresh times but may provide more accurate results, especially with regard to complicated motions. Together with the Display path, steps property, the refresh time also determines how often the simulator renders a body's path. Return to Contents Gravitational Potential Properties These two properties should only be used in conjunction with the gravity source element. Show zero level of gravitational potential energy: Show the zero level as a thick dashed green horizontal line. Zero level of gravitational potential energy: The Y coordinate (in meters or another distance measure) of the zero level line. Default value is zero. Return to Contents