make a stroke from a path in after effect

Question

I'm moving an object and I would like to make a track that "follow it", I would like to make a path stroke (that I will animate, trimming it) from the path of the object I move

Answer 1

There are many ways to do this - here is one:

1. Make a null object
2. Make a mask path on the null layer using the pen
3. Set a single keyframe on the mask's path
4. Go to your object (e.g. a star in this example)
5. Make a single keyframe on its position
6. Copy your mask path keyframe
7. Select your position keyframe
8. Paste, and you should see your object now moves along the path

To make a tail that follows the star:

1. Add a new shape layer with a single line in it
2. Make a keyframe on that line's path
3. Copy the path from your null
4. Paste it into your new shape layer.
5. Now you will have a line the same shape as your star's path.
6. Add a Trim Paths effect to your Line layer
7. Animate the 'End' control on the Trim Paths effect to get the path you need.

This set of scripts is excellent, and free. http://www.redefinery.com/ae/rd_scripts/ It includes scripts such as "shapes to masks" and "masks to shape". Highly recommended

Answer 2

Please tell me you are not looking for optical flow