Wind Sway Rig for Aseprite

Grass, bushes, trees, banners and hair move in the wind, but animating them by hand is tedious. Wind Sway Rig generates the loop from the sprite you already drew: pick a root, and the base stays planted while the tip bends. Rows move by whole pixels only, so there is no blending, no new colour and no change to your transparency; the loop closes exactly and is tagged wind.

• Root: bottom of the drawing, top (hangs down), a row number, or the bottom/top edge of your selection; rows beyond the root never move
• Bend profile: linear, ease-in (tips move most) or stiff base (rigid lower part, zone size in %)
• Travelling wave: the sprite is cut into column bands with a phase step per band, so a field of grass sways as a wave instead of in unison; plus a gust envelope
• Exact loop: 2-64 frames, 1-8 sway cycles per loop, frame N equals frame 0; amplitude 1-32 px
• Presets for grass, tree, flag / banner and hair / cloth; edge behaviour crop or wrap-around
• Layers: active layer or all visible layers with a strength per layer (foreground grass stronger than the trees); one Ctrl+Z undoes everything; RGB, indexed and grayscale, Aseprite 1.3+

How it differs from other wind tools and from Idle Motion Maker

	Wind Sway Rig	Heos Wind (Heosphorus, as listed on itch.io)	Idle Motion Maker (whole-sprite sway)
Root	row, edge of selection, bottom/top of drawing	painted anchor layer, distance field	none, the whole sprite moves
Colour modes	RGB, indexed, grayscale	RGB only, per its page	RGB, indexed, grayscale
Output	whole-pixel row shifts, every pixel copied from your sprite	distance-field warp with presets	whole-sprite shifts
Loop	frame N == frame 0, tested	loop or gust mode	loop

Honest note: Heos Wind has more tuning controls (painted anchors, jitter, scatter, carry mode) and costs about the same; this tool is the simpler, stricter one: pick a row, get a rooted pixel-exact loop, in any colour mode, with no new colours. The delta is based on that tool's public page, not on running it.

Tested in real Aseprite 1.3.18 (headless) on RGB, indexed and grayscale sprites, odd and even sizes, semi-transparent pixels, offset cels, multi-layer sprites and selection roots: root row never moves, displacement never decreases with distance, loop closes, only the colours already in your sprite, one undo step. Neighbouring wave bands can differ by whole pixels, which gives a small stair-step at band borders (pixel-art look); use a wide band or 0 % wave for a smooth block. A pole or trunk that must not sway belongs on its own layer. Commercial use of the resulting artwork is allowed; no credit needed.

Try the free Lite version first: Wind Sway Rig Lite.

More Aseprite tools by the same author: Shine & Glint, Parallax Loop Studio, Appear & Vanish FX, Hit Reaction Kit, Idle Motion Maker (whole-sprite bob and sway), Smear & Squash Studio, Selective Outline Studio, Pixel Sky & Cloud Generator.

Disclosure: the code was written with an AI coding assistant; the effects are plain pixel maths, no image AI.