Thanks for answering but yeah it doesn’t entirely answer my question. I use .tga format for all my textures exported from substance painter and or photoshop. Photoshop exports are in 24 bits/pixel and substance painter only has an option for an 8 bit export, I’m assuming this is 8 bits per channel.
Secondly, yes I know you can combine roughness, metallic and specular into a singular texture but I rarely need all three. Mostly I often just need the roughness map on its own. If I were to import just the roughness into the engine as a single texture which compression settings should I use, if it even makes a difference. If you don’t know which compression settings I mean, they’re in the details panel when you open up a texture in unreal.
Primarily I just want to know whether having this single roughness map as a texture will take up as much space/memory as a diffuse map that has all three channels filled or does unreal automatically handle this part when you export your final project?