MovieClip

I built this because AE's pre-comp command always frustrated me. Whenever you pre-comp a selection, After Effects creates a new comp that's the same size as the entire parent comp, not the size of what you actually selected. That becomes a problem the moment you try to click on something underneath it. AE picks up the pre-comp layer first because its bounding box covers the whole scene. You end up having to dig through the layer panel every time just to find and select what you wanted. It's annoying and it wastes time.

What I wanted was a pre-comp that only takes up the space of the layers inside it, tight to their bounding box. Nothing more. So clicking around your scene stays easy even after grouping things together.

I named it MovieClip as a homage to Flash. Back in Flash, you could select anything on the stage, hit F8, give it a name, and it became a MovieClip symbol with its own timeline, placed right back where it was with tight bounds. It was one of those features that just felt right. After Effects never had anything like it, so I made my own version.

Select any set of layers in your comp, run the script, give it a name, and they get packaged into a new child comp sized to their actual bounding box. The parent comp gets a single pre-comp layer dropped right where your selection was. Transforms, keyframes, and expressions stay intact. No extra nesting, no manual repositioning, no cleanup.

How to install

In After Effects, go to File → Scripts → Open Script File... and select MovieClip.jsx. Or drop the file into your AE Scripts folder and restart. It will appear under File → Scripts from then on, and you can assign it a keyboard shortcut like F8.

How to use

Select one or more layers in your comp, run MovieClip, type a name, click OK. The selected layers move inside a new child comp. The parent comp gets one clean pre-comp layer in their place.

Limitations in v1

3D layers are not supported. Bounding boxes are computed at the current playhead position. For layers whose shape changes significantly over time, the box reflects that one frame, the same way Flash baked symbol bounds at edit time.