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How to Export a Sprite Sheet for Unity or Godot

Pack sprites into one file, understand the JSON atlas that comes with it, and get it into your engine.

What a sprite sheet actually is

A sprite sheet is a single image containing many smaller sprite frames laid out in a grid. Engines load one texture instead of hundreds of individual files, which is faster to load and easier to manage. Alongside the sheet, an atlas — usually a small JSON or XML file — records where each frame sits: its x/y position and its width and height in pixels.

Packing a sheet with the Sprite Sheet Maker

Generate or draw a sprite in the Sprite Sheet Maker, then open the Sprite sheet + atlas panel in the sidebar and set three things:

• Count — how many seeded variations to generate (up to 256)
• Cols — how many frames wide before it wraps to a new row
• Scale — the per-frame pixel scale on export

Click Export sheet + JSON. Two files download: a single PNG sheet, and a JSON atlas listing every frame's position.

Reading the atlas

Each entry in the atlas looks roughly like this — an array of frames, each with pixel coordinates on the sheet:

{
  "frames": [
    { "x": 0,  "y": 0,  "w": 32, "h": 32 },
    { "x": 32, "y": 0,  "w": 32, "h": 32 },
    { "x": 0,  "y": 32, "w": 32, "h": 32 }
  ]
}

That's all a game engine needs to slice the single PNG back into individual sprites.

Using it in Unity

If every frame is the same size (which it will be, since a sheet is built from one generator or canvas), import the PNG and open Unity's Sprite Editor. Set Sprite Mode to Multiple, then use Slice → Grid By Cell Size and enter the frame width/height from the atlas. Unity will cut the sheet into individual sprites automatically, matching the same layout the atlas describes.

Using it in Godot

In Godot, import the PNG as a texture, then create an AtlasTexture resource for each frame — set its Atlas to the sheet and its Region to the frame's x/y/width/height from the JSON. For an animated sprite, add each AtlasTexture as a frame in a SpriteFrames resource on an AnimatedSprite2D node.

Animating instead of packing variations

If you're exporting a walk cycle or other animation rather than random variations, use the timeline's Strip + JSON export instead — it packs your actual animation frames in sequence, with the same kind of atlas.