Is there an effect that can achieve (example video), similar to Echo.

[Yompa]

Please see just a 5 second snippet in the linked video below from 1:45 - 1:50.

I am animating a circle to move along a path. How do I make the circle leave a trail, like a comet tail, as seen in the example video? I tried using the Echo effect, but the result isn't the same because the "comet tail" doesn't shrink in size or doesn't fade; it's as if a sausage is following behind the circle. But in the example video, you can see that the tail shrinks towards the tail-end and sort of fades away like a gradient. Anyone know how to achieve this? Thanks you!

God - YouTube

[imeilfx · Accepted solution]

Echo in that case is not the most efficient tool to achieve what you need. Here in that clip you have nothong more than tappered line traveling along path.
To do that i guess the easiest way would be to use 3rd party plugin called 3D Stroke that works similar to built in Stroke but have tappering and bunch of other features. But you have to pay for it. Second solution would be to use free VC plugin called Saber. And third one I have in mind would be to make some more complicated work (but learn bunch of new stuff if you are a beginer along with it) following those tuts: Create A Tapered Stroke in After Effects: Part 1 - YouTube  and Create A Tapered Stroke in After Effects: Part 2 - YouTube

[Yompa]

I know this is late. But thank you so much!