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GameMaker Sprite Strip Maker — _stripN per Animation

GameMaker wants one sprite per animation, and its strip importer reads the frame count from _stripN in the file name. This export cuts one strip per tag with every cell aligned on the pivot — built the way that importer cuts strips, but not loaded in GameMaker here.

Drop a sprite sheet, numbered frames, a GIF / APNG or an .aseprite file
Runs in your browser. Files are not uploaded.
Studio Sprite workspace: a 48 px samurai sheet with the detected grid, 60 frames in 10 animations, before Apply
The real Studio with a CC0 asset (OpenGameArt).
Exports to
  • GameMakerUNVERIFIED
  • Godot 4Verified· Godot 4.7.2
  • Unity 6Verified· Unity 6000.5.3f1
  • Phaser 3 / 4Verified· Phaser 3.90 + 4.2
  • PixiJS 8Verified· PixiJS 8.21
  • Aseprite JSONVerified· Phaser load.aseprite · PixiJS 8.21
  • .asepriteVerified· Aseprite 1.3.18
  • Spine / libGDXVerified· spine-canvas 4.2
  • Starling / Sparrow XMLVerified· Phaser 4.2
  • LÖVEVerified· LÖVE 11.5
  • DefoldBuilt· Defold bob.jar 1.13.1
  • CSS spritesVerified· Chromium
  • GIF / APNGDecoded· Pillow

What it does

  • One PNG per animation named spr_<name>_<tag>_stripN.png, N = frame count.
  • Cells aligned on the pivot, so the origin is the same in every frame.
  • gamemaker.json with each sprite's origin, speed and per-frame milliseconds.
  • UNVERIFIED in GameMaker: there is no headless GameMaker to test with; the strips were cut and compared with the source.

How to do it

  1. Drop the sheet and press Apply (or drop frames, a GIF or an .aseprite file).
  2. Name one tag per animation and set the pivots.
  3. In Pack & Export choose GameMaker.
  4. Import each strip in GameMaker and set the origin from gamemaker.json.

Engine exports and how each was checked

"Verified" means the exported files were loaded by the real engine or tool on real CC0 assets and the result was compared with the source. Anything that was not loaded is labelled as such.

TargetFilesCheck
Godot 4.tres SpriteFrames · .tscn AnimatedSprite2D · .png.importVerified Godot 4.7.2Loaded by Godot; every animation frame drawn and compared with the source file. The scene uses Nearest filtering; rotation is never used.
Unity 6.unity.json · Editor/NerulioSpriteImporter.cs · AnimationClipVerified Unity 6000.5.3f1Batch mode: sprite rects, pivots, pixels, clip keys and durations checked.
Phaser 3 / 4atlas JSON (multiatlas) · .anims.jsonVerified Phaser 3.90 + 4.2Frames and animations drawn by both versions.
PixiJS 8spritesheet JSON · animations · anchor · meta.scaleVerified PixiJS 8.21Rotated and multi-page atlases included.
Aseprite JSONhash / array · frameTags · slicesVerified Phaser load.aseprite · PixiJS 8.21Tags keep their direction and repeat count.
.asepritelayers · tags · durations · slicesVerified Aseprite 1.3.18Opened and rendered by the Aseprite command line.
Spine / libGDX.atlasVerified spine-canvas 4.2Every region drawn by the Spine runtime, rotated and trimmed; libGDX itself was not run.
Starling / Sparrow XMLXML per pageVerified Phaser 4.2Phaser 3.90 draws trimmed XML frames wrongly (its own bug); the "Sparrow XML (Phaser 3)" preset turns trim off and passes in 3.90 and 4.2.
LÖVELua quads · nerulio_atlas.lua · main.luaVerified LÖVE 11.5Every frame drawn and every animation stepped through the shipped helper.
Defold.atlas · .tilesourceBuilt Defold bob.jar 1.13.1Built by Defold's command-line builder; the built texture's UVs were read back.
GameMakerspr_<name>_stripN.png · gamemaker.jsonUNVERIFIEDNot loaded in GameMaker (no headless GameMaker). The strips are cut the way its strip importer cuts them.
CSS sprites.css · preview .htmlVerified ChromiumEvery class drawn from the shipped stylesheet.
GIF / APNGone file per animationDecoded PillowEvery frame and delay decoded again after export; APNG is exact.

Evidence

GIF decoder: 408 of 408 frames identical to Pillow on 29 real GIFs; APNG 132 of 132 on 16 files. .aseprite: 231 corpus files imported, re-written and reopened in Aseprite 1.3.18 with the same tags, durations and pixels (231/231). Exports: 49 runs in the real engines on real CC0 assets, 47 pass — the 2 failures are Phaser 3.90's trimmed-XML bug, which the Phaser 3 preset avoids.

Limits

  • A grid or island guess is a preview with a confidence; nothing is cut until you press Apply, and every choice has one-click alternatives.
  • .aseprite files whose layers do not compose exactly (e.g. group opacity) are imported flattened, and the Import panel says why.
  • Rotated frames in an imported atlas stay rotated; their export is UNVERIFIED.
  • Images up to 32,768 px per side (268 million pixels), subject to your browser's memory.

Questions

Was this tested in GameMaker?

No. GameMaker cannot run headless here, so the export is labelled UNVERIFIED; the strips were cut the way GameMaker's strip importer cuts them and compared with the source frames.

Does GameMaker read the timing?

Strips carry no timing; the speed and per-frame milliseconds are in gamemaker.json for you to enter.

Is it free, and do I need an account?

Everything on these pages is free and works without an account. There is no watermark and no export that is held back.

Are my sprites uploaded?

No. The Studio decodes, packs and exports in this browser tab. Projects are autosaved in the browser (IndexedDB) and can be saved as a .nerulio file.

Does it need Aseprite or an engine plugin installed?

No. .aseprite files are read and written in the browser, and each engine bundle carries what that engine needs (for Godot, the import settings and scene; for Unity and the Godot TileSet, a small editor script).