Follow trajectories


1. Turning a point into a trajectory follow

Add a cross marker on the point you wish to follow. Use the context menu Follow Trajectory.

The trajectory you draw has two functionning mode, an edit mode where you define the trajectory, and a normal mode where you can interact with it. 
Upon initialization, the trajectory is in edit mode.


Note: While in edit mode, the whole trajectory is semi transparent.In normal mode, the part that is before the current frame is opaque.


2. Define the successive positions of the trajectory

Drag the target to move the point associated to the current image.

Move forward one frame. The new position for the target marker defaults to the same position as the previous frame.
use the mouse wheel or the right key to move frame by frame.
On each frame, move the target to the new point location by drag and drop.

Explicitely end the trajectory edition using the context menu End Trajectory Edition.



3. Interact with the trajectory

When the trajectory is in normal mode points positions are locked.

Click on the trajectory to automatically jump the video to the corresponding frame.
Similarly, drag the target along the trajectory to browse the motion in time.

Trajectory hide itself after the last point specified.


 If some points are misplaced, go back into edit mode using the context menu Restart Trajectory Edition, move the point, and go back into normal mode.


4. Changing trajectory display

Use the context menu Configuration to access the corresponding dialog box.
You can modify the color and style of the trajectory draw, and specify if you want the labels of key images hapenning during the follow to be shown.



See also:
° Measure timeframes
° Draw and comment key points
° Leverage flat grid and perspective grid
° Save and share analysis