Autometric

Autometric is a Lua script for Aseprite that automatically converts three flat layers into a clean isometric projection. Draw each face freely (position doesn’t matter), mark the ground with a red line, optionally place a single red pixel to anchor the roof, and let the script do the math.

Features

• Three working layers: created automatically: [ISO] FRONT (left iso wall), [ISO] TOP (roof), [ISO] SIDE (right iso wall)
• Flexible ground control: paint a horizontal pure‑red line to set Y=0 per face. Pixels above become the object; pixels at/below are ignored. No line? Ground defaults to the lowest opaque pixel.
• Roof anchor: a single isolated red pixel in the TOP layer defines the front‑left corner of the roof. No anchor? The roof auto‑centers for symmetrical eaves.
• Multiple isometric ratios – choose from 2:1 (classic), 1:1, 3:2, or 4:3. The preview updates instantly.
• Adaptive Top mode: the roof automatically adjusts height to match the tallest wall below it, perfect for irregular or stepped buildings.
• Real‑time preview: see the assembled result inside the script dialog.
• Single‑frame or full animation: Generate the current frame with Allons‑y! or process every frame of your animation with Animation.
• Clean output: three new layers are created, the working layers are hidden, and the result is centered on the canvas. Regenerating replaces old output.

How to use

1. Run the script. It creates the three working layers.
2. Draw each face in its respective layer.
   • FRONT = left wall, SIDE = right wall, TOP = roof (drawn top‑down, front edge at the bottom of the image).
3. (Optional) Mark the ground. Paint a horizontal line of pure red (R=255, G=0, B=0) anywhere in FRONT or SIDE. Everything above that line becomes part of the wall; the line itself is ignored.
4. (Optional) Anchor the roof. Place a single isolated red pixel in the TOP layer. That pixel becomes the front‑left corner of the roof. (If red pixels touch each other, they’re ignored as noise.)
5. Click Refresh to see the preview.
6. Choose your ratio and enable Adaptive Top if needed.
7. Click Allons‑y! for the current frame or Animation for all frames.
8. Use the Clear button to remove the output and show the working layers again.

Installation

1. Copy Autometric.lua into your Aseprite scripts folder:
2. Restart Aseprite or run File > Scripts > Rescan Scripts.
3. Launch the script from File > Scripts > Autometric (or bind it to a keyboard shortcut).

Requirements: Aseprite 1.3 or later, RGB color mode (RGBA). The script will warn you if the sprite isn’t RGB.

Important notes

• Never rotates or interpolates. It only shears and copies, keeping your art perfectly crisp.
• The output canvas size is based on your current sprite dimensions. If the assembled result is larger, it will be clipped—just enlarge your canvas and regenerate.
• For animations, the script computes a common ground anchor across all frames, so movement stays stable. Frames without a cel inherit from the previous frame.

Tips

• Use the Red button in the dialog to quickly set the foreground color to pure red.
• Adaptive Top works best when your walls have varying heights (e.g., a tall FRONT and a shorter SIDE). It adjusts the roof per pixel so it sits exactly on top of whatever wall is there.
• You can leave gaps of empty space above your ground line. Those gaps become “air” and will float in the isometric result.

Made with ❤️ for pixel artists who love isometric but hate the math.

Example:

Original drawing (Each layer can be drawn wherever you want.)

Results (with Adaptive turned on)

2:1

1:1

3:2

4:3

💬 Feedback & Support

I love seeing how you use Autometric in your projects. If you have questions, ideas, or just want to share what you’ve made, feel free to leave a comment or reach out directly. It’s always great to see your work in action.

If you found this tool useful, taking a moment to leave a rating really helps. Thanks for the support ❤️