After Effects & DaVinci Resolve

Box Cutter

by Will Rosekelly

Box transitions are four minutes of shape layers, keyframes and maths — every single time. This builds them on every cut in the comp, in one pass, in about a second — and the same patterns build split screens, a clip to a panel.

It only ever makes the matte. Your clips are never moved, trimmed, re-timed or touched. You get a layer of animated boxes, sitting above the cut, ready to set as a track matte when you want it — and not a frame before.

7 patterns
Grid, bars, split, slide, scatter, brick, Mondrian
4–18 frames
Or locked to your BPM, on the beat
Every cut
Whole comp in one pass, or just what you selected
Undoable
One Cmd+Z takes back the whole pass
Download Free Try the panel Free to try, capped at three mattes per pass and six boxes per build. Both the After Effects and Resolve versions are in the one purchase.
Grid

Running the real engine from the panel — same maths, same seed, same boxes. Pick a pattern, or switch to the matte to see exactly what lands in your comp. Frames from Zayyde — Revenge and Noluvv, both cut here.

Real output — every pattern cutting on the beat, four split screens off the same layouts, and the panel that built them. No hand-keyframing, and on a transition the matte is all it ever touches.

Live — try it

This is the panel

Not a screenshot. This is the actual panel, running the actual code, with a stand-in for After Effects behind it. Every control works — change a pattern, drag a slider, hit Preview and watch it map out where the mattes would land.

Start with a preset

Eight of them across the top. Or hit Surprise me — it rolls every setting inside ranges that still look deliberate, so you can click through looks until one lands, then save it.

Preview before anything is made

Preview maps every matte onto a strip of the timeline and tells you what it skipped and why — layers stacked on the same frame, a shot repeated over itself, a cut too close to the end to fit. Nothing is created until you press Make mattes.

Read the panel, not the manual

Every control says what it does in plain words. Anything that can't apply to what you've picked greys itself out rather than sitting there doing nothing.

What you're seeing here

The host is mocked, so Make mattes reports what it would build rather than building it. In After Effects the same button puts the layers in your comp.

Not ready yet? I'll email you when there's an update worth knowing about — new patterns, fixes, the odd discount. Nothing else, and one click to stop.

It makes the matte. That's all it makes.

Most transition tools earn their speed by rearranging your timeline — extending handles, nudging clips, dropping in adjustment layers, re-timing what you cut. Then a client note lands, you move one shot, and the whole thing comes apart.

This one builds a shape layer of animated boxes and stops. No clip is moved, trimmed, re-timed, re-ordered or re-linked. Nothing is set as a track matte for you either — that's a decision, and it stays yours. The boxes sit above the cut until you want them.

Because it only ever adds layers, the worst thing a bad pass can do is give you layers you don't want. Remove mine deletes only what the panel made and leaves everything else alone. One Cmd+Z undoes an entire pass.

And it builds split screens

The same partitions that cut a transition — grid, bars, bands, brick, Mondrian — are split-screen layouts. So the panel makes those too: one clip per panel, each framed for itself.

Two-up, three-up, or uneven

Bars gives you columns, Split gives bands, Mondrian gives panels of different sizes. Two presets on the row get you there in one click.

Choose what goes where

Click a panel and pick its clip from the comp. Leave it and the panels take your selected clips in order — select one and they carry on down the timeline from it.

Frame each one by hand

Alt-drag inside a panel to reframe it, scroll to punch in. The preview shows real frames from your own clips, so you can see what you are choosing rather than guess.

Built inside a precomp, so your timeline gains one layer, not one per panel — and like everything else here, nothing you already had is moved.

Enough control to make it yours

Seven patterns is the starting point, not the ceiling. Everything underneath is adjustable, and nothing is hidden behind a preset.

Shape

Rectangles or ellipses. Grid size, gap, inset, corner rounding, rotation, spin. Boxes don't have to fill the frame — dial the dropout and let some of them miss.

Movement

Scale, fade, both, or just appear with no animation at all. Smooth, on 2s, 3s or 4s. Snap, linear, ease or overshoot. Reverse to close instead of open.

Timing

4–18 frames, a fixed length, or locked to BPM with a division and an offset. Stagger and lean decide how the cascade fans out across the boxes.

Where they land

Every clip in the comp, just what you selected, at the playhead, on comp markers, or on the beat. A minimum gap stops them stacking up on each other.

The look

Colour, fill and stroke, opacity, feathered edges, blend mode. Invert to cut the boxes out of the frame instead of revealing through them.

Presets & Surprise me

Eight to start from, save your own, and a Surprise me button that rolls the whole panel inside ranges that still look deliberate. Click until something lands.

Both apps, one purchase

The same engine drives both versions — one seed gives the same boxes in either app, so a look you find in one is a look you can rebuild in the other.

After Effects
2019–2026 · macOS & Windows

A docked panel. Builds shape layers with real keyframes you can open up and adjust by hand afterwards, like anything else in your comp.

DaVinci Resolve
Resolve 18+ Studio · Fusion page

Builds the same patterns as Fusion mask nodes, wired and animated, on the clip you're parked on, and drops the playhead onto the middle of the wipe so you can see it straight away.

Installing

  1. Download BoxCutter.zip and unzip it. It's free — the panel runs in trial mode until a key goes in, so there's nothing to buy before you try it.
  2. Install BoxCutter.zxp with the free ZXP Installer — drag the file onto it, that's the whole job. It'll warn you about an unknown publisher; that's expected, the panel is self-signed.
  3. Restart After Effects. The panel is under Window → Extensions → Box Cutter.
  4. Paste your key once. It checks in about monthly after that, and keeps working when you're offline.

DaVinci Resolve is a separate download — BoxCutter-Resolve.zip. Unzip it and double-click Install on Mac.command (or run python install.py on Windows). It installs itself into Resolve's own Scripts folder and appears under Workspace → Scripts → Edit → Box Cutter. The same key unlocks it.

Get a key

$49
one payment · both apps · yours for good

Free to try without a key, capped at three mattes per pass and six boxes per build — enough to run it on a real sequence and see whether you like what it does. A key lifts both caps and covers three machines.

Questions

Does it change my clips?
No. It adds a shape layer of boxes above the cut and stops there. Nothing is moved, trimmed, re-timed or set as a track matte — you do that when you're ready.
What does the free version do?
Everything, capped at three mattes per pass and six boxes in each one. Every pattern and every control is unlocked, split screens included; you just get three at a time until you put a key in.
Do I need cuts in the comp?
No. Put one at the playhead in an empty comp if you like — a matte doesn't need a cut to exist. Cuts are just the most useful place to put them.
Which versions?
After Effects 2019 through 2026, Mac and Windows. Resolve 18 and up, Studio, on the Fusion page.
Does it need an internet connection?
Once, to activate. After that it works offline — it checks in roughly monthly and keeps working if you're off the grid when it does.
Will it wreck my project?
Preview maps out exactly where every matte will land before anything is made. One Cmd+Z undoes a whole pass, and "Remove mine" deletes only the layers the panel created.
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