Kurve

A free, open-source easing-graph panel for After Effects. Shape a cubic-bézier curve, then apply it to the temporal ease of your selected keyframes — with a preset library you can save, import, and share.

Features

• Bézier graph — drag the handles or type the four values directly.
• Copy / paste cubic-bezier(x1, y1, x2, y2) — round-trips with CSS, code, and other easing tools.
• Apply to selected keyframes — sets native After Effects temporal ease (influence + speed). Non-destructive: your keyframes stay editable, no expressions added.
• Preset library — built-in eases plus your own saved curves.
• Share libraries — export your presets to a .json file and import someone else's.

Install

1. Grab a free ZXP installer — Anastasiy's Extension Manager or the aescripts ZXP Installer.
2. Download Kurve_<version>.zxp from the Releases page.
3. Quit After Effects, drag the .zxp onto the installer (click through the "unverified publisher" note — it's self-signed and safe).
4. Launch After Effects → Window → Extensions → Kurve.

Full steps in INSTALL.md. Requires After Effects CC 2018 or newer.

Use

1. Select two or more keyframes on any property in the timeline.
2. Shape the curve (drag handles, type values, paste a cubic-bezier(), or pick a preset).
3. Click APPLY.

Each consecutive pair of selected keyframes gets the curve applied to the ease between them, so you can ease a whole run at once.

Native ease means no overshoot. Because Kurve writes real keyframe ease (not expressions), a single ease can't overshoot past a keyframe's value — so bounce / elastic / back curves aren't reproduced. Standard power/smooth eases are exact.

Build from source

No build step — it's plain HTML/JS + ExtendScript.

• Dev install: enable unsigned extensions (PlayerDebugMode), then run sync.ps1 to copy the folder into AE's CEP extensions directory. See INSTALL.md.
• Package a release: ./package.ps1 signs a .zxp with Adobe's free ZXPSignCmd (path set at the top of the script).

Architecture

Layer	File	Role
Panel UI	client/index.html	Bézier graph, presets, bridge (HTML/CSS/JS in a CEP panel).
Engine	host/kurve.jsx	ExtendScript — converts the curve to per-keyframe temporal ease and drives the AE DOM.
Manifest	CSXS/manifest.xml	CEP extension manifest.

The panel calls the engine over the CEP bridge (__adobe_cep__.evalScript('KV_fn(...)', cb)); the engine returns "OK|msg" / "ERR|msg" strings.

License

MIT © Kyle Sullivan