Smart Precompose.json (85.7 KB)
Name - Smart Precompose
Description -
This automation precomposes the selected layer (or layers) and leaves all the attributes of the original file, while keeping the length used in the composition. If the layer is time remapped, it will also keep only the part that is actually used.
Cool… I tried to run it and maybe I didn’t understand exactly what it’s all about.
It precomposes each Layer in dependently but doesn’t precompose multiple layers into a single composition?
I didn’t investigate thoroughly, but it’s also worth mentioning in the description or with a user alert message that you delete layer comments… I wouldn’t want a script doing that without notifying me because I might use a comment for something else…
Sharing these automations is awesome!!!
Thanks Planlisn… you rock 
Thanks for the notes! I updated the description with a warning. Currently, the layer comments is the best way I know to store information.
Let me try to explain better what this automation is meant for:
It’s kind of a mix between the two ways of precomposing.
If you leave all attributes, you keep all the changes you made to the layer outside of the precomp, but the problem is that the precomp contains inside the whole length of the original footage. If you then try to manually shorten it and keep only the required part, it messes up the position of the keyframes and the the In/Out points.
If you move all attributes, you get a precomp that is the correct length, but all the changes you made to the layer are now inside the precomp.
This automation leaves all the attributes outside of the precomp, but keeps only the part of the footage that is actually used inside the precomp.
You can’t precompose multiple layers together while keeping the layer attributes outside of the precomp, that is why it precomposes each layer individually.
Nice.
Thanks for elaborating 
I helped to create this one, in general a very useful, smart and reliable automation.
Maybe in future I will add a new collection variable that will be able to store many items. Then you won’t need to use the layer comment to save if selected.