A trajectory is a line that shows the path traveled by a selected object across a selected interval
Tools for switching Trajectory rendering modes can be found on the UI panel at the top
1. Parent trajectories
If you select a group object, trajectory will be rendered only for the highest one in the object hierarchy
2. All trajectories
If you want to show trajectories for every selected point controller or object, choose this option
3. Edges trajectories
If this option is enabled, trajectories will show the positions of edges connecting selected point controllers.
4. Edges and trajectories fixed
This mode shows positions on the selected point controllers and edges that connect them
Point controllers are shown as green points. In the current frame, they are marked with yellow circles
5. Using only key frames
In this mode, you will see trajectories of the selected point controllers in the keyframes.
To edit a trajectory you need to enable the Trajectory edit mode button. After this, you can move, rotate and otherwise adjust any point of a trajectory by applying standard manipulators.
Note: If you edit a trajectory for one or more frames in an interpolation interval, the interpolation mode for this interval will be switched to Fixed
This button fixes the trajectories on the selectd interval.
When this mode is enabled, trajectories for the selected objects are always redered on the interval you've set, even if you select another interval.
To remove fixing, simply disable the button.