UV Checker Overlay

If you've ever stared at a texture in a game engine and wondered "why is that stretchy region there," the answer lives in the UVs - and the fastest way to see UV distortion is the old checkerboard trick: lay a checker over your albedo and the squares tell you instantly where the UVs stretch, compress, or tear. UV Checker Overlay is that trick as a node, and it doubles as a standalone checker generator for when you need a clean UV test grid. It's the node tech artists reach for without thinking, and it's one of the few things in this pack that's just plain stock-in-trade.

How it works

The node builds a checker pattern from cells_x × cells_y grid cells with line_width grid lines, then does one of two things depending on mode. In overlay mode it mixes the checker over your input image at mix strength (0.75 default) - that's the UV diagnostic, checking a real texture. In generate mode it ignores the input image and outputs the checker pattern alone - that's the clean UV test grid you slap on a mesh to check seams. palette picks the look: uv (the classic blue/white checker), neutral (gray), or mono (pure black/white). invert_pattern flips it.

The real distinction to remember: overlay = inspect a texture you have, generate = produce the test pattern you hand to a 3D app. The optional mask and its mask_feather/invert_mask controls let you restrict the overlay to part of the image.

The inputs that matter

• mode - overlay (over your texture) or generate (bare checker)
• cells_x / cells_y - grid density (8×8 default; the classic UV test is even cells so stretches show clearly)
• mix - how strongly the checker shows over the texture (overlay mode only)
• palette - uv / neutral / mono

Outputs: image (the result), mask, and checker_info with resolved settings.

Installing it

Ships in MKRShift Nodes from criskb. ComfyUI Manager → "MKRShift Nodes", or:

cd ComfyUI/custom_nodes
git clone https://github.com/criskb/MKRShift_Nodes

Restart ComfyUI; it's under MKRShift Nodes → Surface → Tech Art. No models or extra deps - numpy/Pillow/torch.

Common gotchas

The pack is too new for community lore, so trust the source. This node uses real widgets, not the pack's JSON convention - no JSON traps here. The one thing that trips people: in overlay mode the checker is blended over the image, so if mix is low and your texture is busy, you'll barely see the grid and wrongly conclude "no UV distortion." Set mix high (0.8+) for a real check. And when you're actually evaluating UVs, use generate mode output as a separate texture rather than eyeballing a blend - a pure checker on the mesh shows stretching unambiguously.