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

1. Generate on a PLAIN flat background (easier to key out than a busy one).
2. Use a background-removal model (e.g. InSPyReNet / rembg) rather than a hard color key.
3. Inspect edges at 400% zoom for halo or fringe pixels.
4. Defringe / decontaminate edge color so no background tint remains.
5. Erode the alpha by 1px if a faint halo persists.
6. Save as PNG with straight alpha; verify on both light and dark backgrounds.
7. 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.