Answers.Body: <p>There are many ways to do this - here is one:</p>
  <ol>
  <li>Make a null object</li>
  <li>Make a mask path on the null layer using the pen</li>
  <li>Set a single keyframe on the mask's path</li>
  <li>Go to your object (e.g. a star in this example)</li>
  <li>Make a single keyframe on its position</li>
  <li>Copy your mask path keyframe</li>
  <li>Select your position keyframe</li>
  <li>Paste, and you should see your object now moves along the path</li>
  </ol>
  <p>To make a tail that follows the star:</p>
  <ol>
  <li>Add a new shape layer with a single line in it</li>
  <li>Make a keyframe on that line's path</li>
  <li>Copy the path from your null</li>
  <li>Paste it into your new shape layer.</li>
  <li>Now you will have a line the same shape as your star's path.</li>
  <li>Add a Trim Paths effect to your Line layer</li>
  <li>Animate the 'End' control on the Trim Paths effect to get the path you need.</li>
  </ol>
  <p>This set of scripts is excellent, and free. <a href="http://www.redefinery.com/ae/rd_scripts/" rel="nofollow noreferrer">http://www.redefinery.com/ae/rd_scripts/</a>
  It includes scripts such as &quot;shapes to masks&quot; and &quot;masks to shape&quot;.
  Highly recommended</p>
  <p><a href="https://i.sstatic.net/SMAYt.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/SMAYt.jpg" alt="screengrab" /></a></p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2020-09-11T10:37:11.100Z
Answers.LastActivityDate: 2020-09-11T10:46:45.177Z
Answers.LastEditDate: 2020-09-11T10:46:45.177Z
Answers.UserDisplayName: tomh
Answers.Body: <p>Please tell me you are not looking for <a href="https://opencv-python-tutroals.readthedocs.io/en/latest/py_tutorials/py_video/py_lucas_kanade/py_lucas_kanade.html" rel="nofollow noreferrer">optical flow</a></p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2020-09-08T09:12:52.070Z
Answers.Text: I'm trying to make a trim stroke effect, but this Is not the problem, the problem Is that usually you start from a stroke and you can make something follow this stroke, making a Path from it
Answers.UserDisplayName: Gianmarco
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2020-09-08T09:13:45.247Z
Answers.Text: But I didnt start from a stroke (a line), I start animating an object moving It, I would like to take his Path and make a stroke (a line)
Answers.UserDisplayName: Gianmarco
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2020-09-08T09:49:40.607Z
Answers.Text: Then you might check Quaternion Slerp; i use it to interpolate human motion between keyframes represent in bvh
Answers.UserDisplayName: xer-rex
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2020-09-08T09:57:03.280Z
Answers.Text: I Will give It a look
Answers.UserDisplayName: Gianmarco
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2020-09-08T09:07:41.453Z
Answers.LastActivityDate: 2020-09-08T09:07:41.453Z
Answers.UserDisplayName: xer-rex
Body: <p>I'm moving an object and I would like to make a track that &quot;follow it&quot;, I would like to make a path stroke (that I will animate, trimming it) from the path of the object I move</p>
  
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2020-09-04T17:34:57.723Z
Comments.Text: Does this answer your question? [How to use After Effects Trim Path with an Illustrator Path](https://graphicdesign.stackexchange.com/questions/49643/how-to-use-after-effects-trim-path-with-an-illustrator-path)
Comments.UserDisplayName: AndrewH
Tags: <animation>
Title: make a stroke from a path in after effect
UserDisplayName: Gianmarco
ThreadText: # make a stroke from a path in after effect
  
  (Asked by: username_0 on 2020-09-04)
  
  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
  
  **Tags:** animation
  
  > **Comments:**
  > **username_1**: Does this answer your question? [How to use After Effects Trim Path with an Illustrator Path](https://graphicdesign.stackexchange.com/questions/49643/how-to-use-after-effects-trim-path-with-an-illustrator-path)  
  
  ---
  
  ## 2 answers
  
  ### Answer by username_2 on 2020-09-11. Score: 2 | Accepted answer
  
  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
  
  [![screengrab](https://i.sstatic.net/SMAYt.jpg)](https://i.sstatic.net/SMAYt.jpg)
  
  
  ---
  
  ### Answer by username_3 on 2020-09-08. Score: 0
  
  Please tell me you are not looking for [optical flow](https://opencv-python-tutroals.readthedocs.io/en/latest/py_tutorials/py_video/py_lucas_kanade/py_lucas_kanade.html)
  
  > **Comments:**
  > **username_0**: I'm trying to make a trim stroke effect, but this Is not the problem, the problem Is that usually you start from a stroke and you can make something follow this stroke, making a Path from it  
  > **username_0**: But I didnt start from a stroke (a line), I start animating an object moving It, I would like to take his Path and make a stroke (a line)  
  > **username_3**: Then you might check Quaternion Slerp; i use it to interpolate human motion between keyframes represent in bvh  
  > **username_0**: I Will give It a look  
  
  ---
  
  