Surface masks that survive binarize
Your surface mask decides what every square metre of your terrain feels like underfoot — and it's the file most likely to silently break between your paint program and the packed WRP. This guide is the workflow that survives repeated repaints without falling apart.
The layer stack
Keep the mask as a layered working file and flatten only on export. One layer per surface, painted in the exact indexed colours your layers config expects — anti-aliasing off everywhere, because a single blended pixel becomes a surface your config doesn't know.
Slope overlays
Generate a slope overlay from your heightmap (a 40° threshold works well) and keep it as a guide layer. Painting grass onto a cliff face reads fine in 2D and looks absurd in-game.
Painting workflow
Work from the satmap, not from imagination: the mask and satmap must agree or the terrain shimmers between two stories. Block in the large reads first — rock, grass, gravel — then detail transitions where players will actually walk.
flatten — indexed colours only, zero anti-aliasing export PNG at full mask resolution run the tiler — inspect two tiles at biome borders rebuild world — walk the border in Buldozer
Fixing seams
Visible tile seams almost always mean the mask and satmap disagree at a tile border, or a stray colour slipped into the mask. Diff the border pixels of the two adjacent tiles before you touch anything else.
More guides coming.