This problem has been driving me crazy for two days and I can’t figure it out. I think I’ve ruled out a Blender bug…I’ve been using 2.82 and I tested the issue with another object and it works ok.
Here’s the issue…
This is a just a dummy texture I made to show the problem. By the way, this happens regardless of whether I use a single UV tile or UDIMS. It happens whether or not I use the original UV map from the imported OBJ, or create a new one.
When painting on the object, everything is OK when first opening the scene. If switch from texture paint mode to edit mode, then back again I either can’t paint in the spot the brush is or I get jagged poly imprints and colors in the wrong spots. It just looks like a mess. Zooming in and out will make the look change, but it still looks like crap. If you look at the UV map, the texture looks good. It’s just the way it draws in the viewport that looks weird.
I tested with another imported OBJ and it works fine. I would love to avoid retopologizing this object. Can anyone think of a reason that an object would make painting such a pain? One other thing I’ll mention is that Blender gets very sluggish when the problem starts happening during painting. My GPU and CPU fans go into overdrive and everything slows down. It only happens with this object.