Hello, I realize that this thread is old. But I couldn’t find any other as relevant as this one for my question.
So knowing that R:Metal G:Roughness (for the extra bit) and B:AO is the way to go.
Is there any particular reason why Substance Painter propose this other setup in their UE4 export preset:
R:AO G:Roughness B:Metallic?
While UE4 docs points to the proposed preset (in this thread): A new, community-hosted Unreal Engine Wiki - Announcements and Releases - Unreal Engine Forums
As long as Green remains the Roughness for the extra bit. There is no difference between R and B in term of compression?
Thank you