Every After Effects project starts out clean. Then the revisions come, and a few weeks in the file has ballooned: old footage you replaced in round two, dead comps from ideas that did not make the cut, solids you made for a quick matte and forgot about. Worst of all, there is no real way to tell what is actually safe to delete. Pull the wrong item and an expression breaks or a nested comp goes dark.
Reducer is a Filmit plugin for After Effects built to find all of that junk and shrink the file without breaking anything. You tell it which comps actually matter, it scans the entire project for everything not tied to them, and you clear the leftovers in one click. The demo above runs the whole workflow in under three minutes; this guide goes deeper on each piece: the scan, expression and child comp awareness, multiple main comps, keep folders, and the safe delete.
This video may reference an older version of Reducer. Features and UI may have changed since recording.
What is Reducer?
Reducer is a project decluttering panel for After Effects. The idea is simple: a finished project really revolves around one or a few main compositions, the ones you actually render. Everything else in the project panel is either feeding those comps or taking up space. Reducer lets you declare which comps are your mains, scans for unused items relative to them, and safely deletes the rest, leaving the project clean and organized.
It installs through Filmit Studio, the free companion app for Windows and macOS, and runs as a panel inside After Effects. Open it next to your project panel, drag in a comp, and you are ready to scan.
Where the built-in Reduce Project falls short
After Effects does ship its own cleanup tool. Go to File, then Dependencies, then Reduce Project, and it will remove unused footage and trim the project down. You can absolutely clean a project that way, and for a simple file it may be all you need.
The problem is what it does not consider. Reduce Project does not respect expressions, so an item referenced only through an expression is not protected, and it does not respect comps you want to keep when they are not inside a main comp. For real projects that is not granular enough, and that gap is exactly why Reducer exists.
Drag in a main comp and scan for unused items
Here is the core loop. The example project is packed with footage, comps, and solids, but the comp that actually matters is Comp 3. Drag Comp 3 into the main composition slot in Reducer, then click Scan for Unused Items. Reducer reads the whole project and returns a list of everything not tied to Comp 3.
That list is the entire product in miniature. Instead of squinting at the project panel and guessing, you get an explicit answer to the question After Effects never answers: what in this file is dead weight? Click Delete Selected and everything on the list is removed, leaving an organized project behind.
Pro Tip: Run a scan before you archive or hand off any project. It takes seconds, and a file containing only what the final comps need is far kinder to a teammate, a client, or future you.
The scan respects expressions and child comps
The reason you can trust that delete button is what the scan counts as in use. Reducer does not just look at what sits in a timeline. It walks the full dependency chain of your main comp: every child composition nested inside it, the comps nested inside those, and anything referenced through expressions along the way.
That last part matters more than it sounds. Motion design runs on expressions, a color controller here, a slider driving a dozen layers there, and those links are invisible when you eyeball the project panel. Because Reducer follows them, an item used only through an expression stays put. What gets flagged is the stuff nothing points to.
Multiple main comps for campaign work
One main comp is the simple case, but real projects often carry several finals side by side. In the demo, dragging both Comp 3 and Comp 2 into the panel tells Reducer to treat them both as mains: everything either one depends on is kept, and only the items that serve neither get flagged.
This feature came straight out of ad work. I have had projects with three different main ads in one file, all three needed to stay, and the only thing connecting them was maybe a shared color controller. With Reducer you name all three as main comps and clean around them in a single scan.
Pro Tip: Before you scan, drag in every deliverable: each aspect ratio, each cutdown, each alternate version the client might still ask about. If it could end up in a render queue, it belongs in the main comp list.
Keep folders for assets you are not ready to lose
Sometimes you want to protect items that no comp uses yet: a folder of GIFs you pulled as options, or Sourcer clips you might still cut in. By the strict logic of a dependency scan those are unused, but you would not want a cleanup to take them.
That is what keep folders are for, and they are optional. In the demo, the GIFs folder and the Sourcer clips folder are marked as keep folders before the scan. Reducer understands it: everything inside them is preserved, while anything outside them that nothing uses, like the stray Comp 1, still lands on the delete list. Delete Selected, and done.
Pro Tip: Set up a keep folder for stock pulls and reference at the start of a project. Then you can scan as aggressively as you like during the edit, knowing the maybe pile is never on the chopping block.
Review the list, delete, and undo if you change your mind
Reducer never deletes anything on its own. The scan produces a list, you read it, and nothing leaves the project until you click Delete Selected. If something on the list surprises you, that is useful information before the delete rather than a broken comp after it.
The cleanup is also undoable. In the demo, a full delete is reversed with a single undo. Between the review step, the dependency awareness, and the undo, the scary part of cleanup, that am I about to break something feeling, is gone.
Key takeaways
Reducer turns project cleanup in After Effects from a guessing game into a scan, a review, and a click.
Declare the comps that matter and Reducer lists everything in the project that is not tied to them.
The scan follows nested comps and expression links, so hidden dependencies never end up on the delete list.
Keep several deliverables in one project, even if all they share is a color controller, and clean around all of them.
Protect folders of GIFs, Sourcer clips, or anything else the scan should never touch.
You review the list, you click Delete Selected, and the whole cleanup can be undone.
Why I built Reducer
Reducer came out of my own bloated files. After weeks inside a project, the project panel stops telling the truth: it shows hundreds of items and no way to know which ones the finals actually need. The built-in route was never granular enough for the way I work, it did not respect my expressions or the comps I needed to keep.
The breaking point was ad campaigns, three finished ads in one project, connected by nothing but a color controller, with no safe way to clean around them. So we built the tool I wanted: declare the comps that matter, protect the folders that matter, and let the scan figure out the rest. Now cleanup is the easiest part of finishing a project instead of the part I avoided.
Get started with Filmit
Reducer installs through Filmit Studio, the free app that manages every Filmit plugin for After Effects and Premiere Pro. One install puts Reducer in your editor and keeps it updated. Need help? The settings button inside the panel links to filmit.io for support and feature requests, and to our Discord, where you can ping me directly.
Reducer is also part of the Filmit suite, over ten plugins in a growing library under one umbrella, so if you use Reducer you get access to the rest. A natural pair is Sourcer, the stock media search panel that drops clips straight into your timeline. Mark its folder as a keep folder and your stock library survives every cleanup.
