CelTween — Motion Tween for Aseprite

Stop hand-placing every frame of a slide, drop or fade.

CelTween tweens the active cel across frames — position and opacity, with real easing curves — the way animation software does it, inside Aseprite.

Features

• 8 easing curves: linear, quad/cubic in, out and in-out, plus overshoot for that springy landing
• Position and opacity tweened together, or either on its own
• One undo — the whole tween is a single transaction, so one Ctrl+Z puts it back
• Auto-extends the timeline if you tween past the last frame
• Overwrite or preserve existing in-between cels

How it works

1. Select the cel you want to move.
2. Run Frame → CelTween: Tween Cel.
3. Set the target frame, the X/Y offset, an easing curve and optional opacity fade. Apply.

Install

Double-click the .aseprite-extension file, or Edit → Preferences → Extensions → Add. Requires Aseprite 1.3+.

Support

Bug reports and requests are welcome in the comments. Made by SpriteWright — see also AutoBlob, the blob tileset generator.

Transparency: CelTween’s code is AI-assisted, disclosed via itch’s AI tagging. It generates no imagery — it only moves the pixels you drew.