Materials vs. Texture Sets I am modeling an ottoman, and need help interpreting the instructions, which say, "Amount of materials should be same as amount of texture sets."

Some info on the model:
My ottoman is one mesh, with a high-poly version baked onto a normal map. The materials are a gray mottled leather with dark wood feet. I have been provided only this texture...



1st question:
So, a "material" is the full node set-up, and a "texture" is any of the maps or images used to plug in to that material's nodes (or just set on the UV mapping). Is that correct? But, then, what is a "texture set"? I would think they mean the group of generated images or textural maps for each of the 9 materials they list here:


Main textures:


BaseColor (sRGB)
AO (Linear)
Roughness (Linear)
Metalness (Linear)
Normal (RGB)
Opacity (Linear)
Emissive (sRGB)

Additional textures: Glossiness, Specular


Here are the other relevant instructions:


Single UV set per model, multiple textures sets if extra resolutions is needed
Only square textures, 4096x4096 resolution
Normal maps baked from hi-poly models
Metalness &amp; Specular workflow maps needed


...

What I would normally think to do in making a model like this is to apply a material to each part (one for the leather, one for the feet), then use a multi-noded setup for each one, including procedural texture for the basecolor, the provided texture image for bump and light-related maps (the baking of which I will be figuring out on the fly), the baked normal map I have from the high-poly mesh, plus certain settings on the Diffuse Shader.

It seems to me that this does not meet the following requirements:

Metalness &amp; Specular workflow maps needed (This confuses me anyway, as I've never really heard of using every single map, and I thought Metalness &amp; Specular were generally used one or the other. Also, can you even bake a procedural color into a image map?)

Amount of materials should be same as amount of texture sets (It seems like I will have 2 materials and something like 9 textures, so what really differentiates a texture set from a material in this context?)

Can someone set me straight, and maybe help me figure out the workflow here?
A "texture set" is the full set of textures for a material, as you've listed above.  For example, diffuse, specular, roughness, metalness, etc. = 1 texture set.  If you download a PBR material from a site like CC0 Textures, what you get is 1 texture "set."

I'm interpreting this requirement to mean that they want separate materials with separate texture sets.  In other words, don't put the leather and wood on the same maps.  You could of course put the all of them into one texture set, with just different parts of a map defining different material parameters but it sounds like they want it separated by material.

So the "leather" material would have its own diffuse, spec, etc., and the "wood" material has its own textures as well.  Sounds like this was your plan anyway.

Secondly, you are correct that Specular and Metalness are usually two different workflows.  I think your client wants the flexibility to be able to use either one.  Maybe they aren't sure which renderer they will use in the end.