Diagonal artifact in UV Layout

I have no real information about this other than it appears in everything.

Here it is with nothing selected. My scene has many objects, maps, materials and layers and I don’t remember when this first appeared. It doesn’t seem to affect any mapping but what the heck is it? It’s now breaking my concentration.

It doesn’t appear in any other Blend file so I’m wondering if it’s the result of some flaw I made in my workflow earlier.


Is it a Greace Pencil stroke? It doesn’t quite look like it, but maybe. Look in your UV window, Properties panel (N key ) , and delete any Grease Pencil layers.

got a blend file?

I’ll check the grease pencil - files too big to be convenient to share, 45MB. I’ll also try to recreate the problem.