We have a simple bouncing ball animation from a training course that is perfect for this example. Let’s see how to add a motion trail.
Make sure the menu set is set to ‘Animation’:
The ‘Visualize’ main menu item will appear, it contains a number of tools for tracking the path of our animation objects:
Create Editable Motion Trail
Press the option box to open the options menu:
Time range: The option to set up the motion trail for either a specified start and end time or based on the length (in frames) of the time slider.
Use start/end if the animation on the object does not last for the entirety of the frames in the time slider. For example you may have a car that moves past a scene of 200 frames, and the car is only animated for the first 120 of those frames, so you would only want a motion trail for the car object from frame 1 (Start time) to 120 (End time).
Show frame numbers: Shows the frame number directly on the motion trail, this is a handy option!
Click ‘Create Motion Trail’, The objects motion trail is now visible complete with keyframe numbers:
As we play our animation the motion trail turns red, indicating the frames of the animation which have been played:
Updating an arc directly on the motion trail
If a change is made to a channel value on a keyframe (translateY for example), the motion curve will automatically update.
For this example I am going to change the Y channel value, and will be turning on ‘Auto keyframe’ to make things a little easier:
Move the time slider to an existing keyframe and move the object in the workspace, the motion trail will automatically update the reflect the new Y channel value for that keyframe: