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I am downloading textures from online and I have found where to plug most of the on a principled shader from online. There is a map called mask, and after further research I am unsure what this does or how to apply it through a principled shader.
To be clear: I am still unsure that textures the mask would be mixing, as a mask doesn’t seem to be applicable to the other textures.
Textures downloaded from cc0 textures