UV Checker Generator

Every 3D artist learns the same lesson the hard way: you can spend an hour baking a beautiful albedo, only to find the model's UVs stretch it into a smeared mess. UV Checker Generator exists to catch that before you waste the hour. It produces a synthetic test pattern you apply to a model in Blender, Unity, or any engine to check whether UV islands are even, which way texture channels are oriented, and how dense your tiling is.

It's a one-trick node - generate a pattern, save it, assign it to the model's base color slot - but it's the kind of trick that makes the rest of a PBR pipeline trustworthy.

How it works

The generator builds a coordinate grid on the GPU, then draws one of four patterns:

• grid - colored cells separated by thin white grid lines. Rainbow mode maps the cell position into R/G/B so you can instantly spot channel swaps and flips.
• checker - the classic black-and-white chessboard. This is the one you want for the standard "are my UVs stretched?" sanity check.
• gradient - a simple U→red, V→green gradient, useful for spotting orientation issues and mirroring.
• numbered - the name promises tiles with numbers on them, which is great for dense atlas layouts… and it doesn't deliver. In the shipped code this mode falls through to the same grid pattern, no numerals drawn. Don't design a workflow around it yet.

Inputs

The relevant knobs:

• width / height (256–8192, in 256 steps) - output resolution. Power-of-two sizes keep game engines happy.
• pattern_type - grid, checker, numbered, or gradient.
• grid_size (2–32) - how many divisions per side. An 8×8 checker is the standard; 16+ is for spotting density problems.
• color_mode - rainbow, grayscale, or red_green. Only affects the grid pattern.

Everything flows to one output, uv_checker (IMAGE) → Save Image → apply to your material in the engine.

Installing it

UV Checker Generator comes from the ComfyUI-TextureAlchemy pack. In ComfyUI Manager, search "Texture Alchemy" and install, then restart. Manual route:

cd ComfyUI/custom_nodes
git clone https://github.com/amtarr/ComfyUI-TextureAlchemy
# restart ComfyUI

No extra dependencies and no model downloads - it's pure PyTorch. The node lives under Add Node → Texture Alchemist → Analysis. (The README's instruction to copy a ComfyUI_PBR_MaterialProcessor folder is a leftover from before the pack was renamed; use Manager or git clone.)

Using it like you mean it

Two quick wins. First, checker + a 2x2 or 4x4 tiled texture: apply the checker to your mesh and screenshot it - if the squares are uniform across the model, your UVs are fine and any future texture problems are the texture's fault, not the UV's. Second, red_green on the grid pattern shows you the U/V axes directly, which is how you catch a flipped or mirrored normal map before it bites you in the renderer.