Lately I have been experimenting with scaling textures in the engine. I use a lot of 2K textures for walls (I try to avoid tiling textures as much as possible and yes I am aware of methods on how to mask tiling so it looks more organic) and I have noticed that I can reduce the base color texture size to 512 and there is very little difference in quality as long as my Normal map stays at 2K. The same goes for Roughness. My question is if this is a common practice or what I am doing might cause other issues? My goal is to free up some VRAM while maintaining good quality.
Might not be the most common practice, but indeed, there is no reason not to use this approach if it suits you. The most resolution-sensitive map is normals anyway.
I’ve definitely seen write-ups showing and saying normal maps benefit most from higher resolutions, and it’s part of the reason you hear about tiling detail normal maps. For base_color, the main time players will definitely notice lower resolutions is with text, but you can get around that with decals.
Exactly. Normal Maps are the most important part of a texture, because it alters the lighting on a surface.
You can neglect BaseColor a bit, since you get the most details out of the other maps.(Metallic is most of the time either 0 or 1 anyways)
BaseColor < Metallic < Roughness < Normal