0xheycat Transparent Cutout Cleanup
Overview
AI-generated sprites come on a background. Naive removal leaves a colored halo or jagged edge that screams amateur when tiles are placed together. This skill produces clean, premultiplied-safe alpha cutouts.
When to Use
- Any generated sprite needs a transparent background.
- Placed sprites show a white/gray halo or fringe.
- Edges look jagged or have leftover background color.
Process
- Generate on a PLAIN flat background (easier to key out than a busy one).
- Use a background-removal model (e.g. InSPyReNet / rembg) rather than a hard color key.
- Inspect edges at 400% zoom for halo or fringe pixels.
- Defringe / decontaminate edge color so no background tint remains.
- Erode the alpha by 1px if a faint halo persists.
- Save as PNG with straight alpha; verify on both light and dark backgrounds.
- Batch the cleaned sprites for the atlas packer.
Pair this with the ComfyUI rembg node in seamless-isometric-terrain/scripts.
Rationalizations (Stop Lying to Yourself)
| Excuse | Reality |
|---|---|
| "A white halo is barely visible" | On a dark tile it is glaring. Defringe every sprite. |
| "Hard color-key is faster" | It eats anti-aliased edges and looks jagged. Use a proper matting model. |
Red Flags - STOP if you catch yourself:
- Visible halo/fringe when placed on a contrasting background.
- Jagged, aliased cutout edges.
- Background color contaminating semi-transparent pixels.
Verification
You are NOT done until every box is checked:
- Edges are clean at 400% zoom on light AND dark backgrounds.
- No background-color contamination on semi-transparent pixels.
- All sprites exported as straight-alpha PNG.