Thanks for reading! There’s no hard linking of anything. Only objects that render to Custom Depth will cause a trail. In the project, I also have them rendering to Custom Stencil but this isn’t required, I just forgot to reset it.
Note that this effect may not work properly if you’re using Custom Depth for other effects as well. If you do have an issue, I would try adding your actors to the scene capture’s Show Only list. You can read more about that in the grass trails tutorial. I haven’t tried this though so I’m not sure if it’ll solve anything.