You could increase your ambient light intensity to until they disappear.
This looks like shadow acne. You can probably adjust the .bias on your shadow casting light to fix it.
Because of this area, I’m inclined to think the wavy lines could be a Moiré pattern … it happens with textures made of parallel lines that are looked at from specific points of view. You cannot remove this pattern, as it is something inherent to all raster displays. You can only reduce its effect with proper blurring, antialiasing, manual mipmaping and anisotropic filtering.
To check whether this is a Moiré pattern, move the camera – the pattern should change. When you try to get very close to the wavy lines, they should disappear.
Demo of a texture-based Moiré pattern:
Moire effect and color bending are two different things. I had problems with the latter.
I used dithering to improve this and just dithering once brought significant improvement.
Strong color bendings without dithering
dithering once, much better
I wonder what effect dithering would have on the moire effect? Does anyone have experience with this?
The moire in your first picture certainly looks like shadow acne. Turn off shadows on your light. If the moire goes away, it’s shadow acne.
Color banding looks different and yes . Material.dithering or .dither either (I can’t remember which) can help with that.
To get rid of shadow acne but still have shadowing, you will have to adjust light.shadow.bias
Yet a 3rd source of visual noise is due to texture filtering/mipmapping not being enabled, as pavel described. If you’re loading using textureloader or loading a gltf, filtering should be enabled by default.