Is there a filter / effect in AE that will generate trails after bright spots? You have certainly seen photos of the starry night, where the shutter has been open for a long time. The stars make nice circular trails, centered around Stella Polaris.
I want the same. In fact, I have a video made in daz3d Carrara, camera placed on a rotating globe, and the starry night rotates above. I want to illustrate this, giving the stars "trails", like in time elapse photos.
If your bright spots are animated solids or particles from one of the stock plug-ins then you'll need to Pre-compose the layer with the bright spots before applying Echo. If you have animated a bunch of bright spots on different layers then you can pre-compose all of them.
Increasing the number of echos and decreasing the time interval will give your streaks. Beware of long render times. Echo can easily take 4 or 5 minutes a frame for HD comps if your number of echos numbers in the hundreds.
Precisely what I am after, thank you!
I have no prefomance issues here. Even with 600 echoes it renders almost in realtime. I have a video with the sky fille swith stars, and using Echo, I am able to show how everything rotates around Stella Polaris (the polar star), Stella Polaris being the only one with no (practically no) trails.