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Automatic Point and Line Tracking

This tool draws point and line tracks (as the manual tracking tool) by animating the movement of a single point along a line or circle. First select one or more points or lines to be tracked. Hold down the Shift-key, if more than one object should to be tracked. Then select a point on a line or on a circle, a slider or an expression, or a line or circe. In the latter case, you need to select the point to move on this line or circle too. The point will be moved, or the slider or expression be changed, creating the tracks of the selected objects.

Should the first tracked object become invalid due to an invalid intersection, the movement is automatically reversed. In case the first track point becomes invalid because two circles no longer intersect, the other intersection point will be chosen when the moving point reverses its movement. Thus the construction runs through all possible states.

The animation speed can be reduced or increased with the shift key and the left or right arrow keys. Repeated left mouse button clicks cycle the animation through 3 modes: animation and track, animation and hidden track, track with no animation. In the last mode the moving point can be dragged with the left mouse button. Other points can be dragged with the right mouse button at any time, but while this is done, the track will be hidden and any animation paused.

If a construction file is saved with this tool as active tool, it will become active when the file is loaded.

To stop the animation and clear the tracks, select any tool., or press Esc.

Permanent Tracks

To make the first track a permanent construction object, press shift and enter, or select the automatic track tool with the control key. A new object will be created using the currently selected color and weight properties. The track can be edited in the same way as any other object. It is possible to create intersections between the track and other objects, and to put points on the track.

Tracks saved this way are calculated at every change in the figure, which may slow down the program on older computers. It is therefore wise to limit the number of tracks, and to restrict their lengths to reduce the calculation load. Moreover, it is possible to turn the calculation of a track off or on by using the fixed checkbox in its properties dialogue.

Related topics: Manual Point and Line Tracking, Points, Animation

Next topic: Animation