Trying to get into making models for Microsoft Flight Sim, need some answers

Till now i have only done modelling and textures in one way.

All my model parts are in one single part and all my textures are all in a single layer.

But here in this video https://www.youtube.com/watch?v=e0uKPWn2p8Y&list=LL&index=1&t=3631s

this guy has so many parts of his building and each of them seem to have a texture of their own selection and their own UV’s probably. but when he exports everything gets rolled in one file.

I dont know this kind of modelling/texturing. How does it work? If i use a brown matcap for part A and Clear Matcap for part B and then export them, how do they get structured in the final file?

That tends to happen with exported files, it’s same exporting FBX to Substance, where you need to ensure no models using the same materials have overlapping UVs.

so i need to separate UV’s to their own spaces, just like i do with my one layered models?

If it uses the same material, yes, if it’s a different material, probably not. That’s how SP works, as it treats a texture based on the material name, so expects one UV for anything assigned that material name. Note, that doesn’t mean hte whole object, just those faces which have the same name.

ok so my question really becomes then…

how can i import materials [PBR etc] directly into blender for each parts of my building and then ave them all together?

is there a guide?

Till date i just used a Diffuse BSDF and imported an image file. But i just want to directly import materials instead of a final image i first make OUTSIDE of blender.

Well importing PBR is as easy as importing an image as you can use node wrangler and use ctrl+shift+T to select all maps, (metal, diffuse, normal, roughness).
To put htem all together into one image requires you think about how you want the model textures exported, if it’s just one single material/uv for everything, then that is going to be an issue as you have to accept you’ll need a huge texture size and even then, you’ll probably end up with areas which look blurry, you’d need a secondary UV there and bake from one to another, not ideal. I don’t know how Flight Simulator imports its objects, if it can handle multiple materials per asset, that is the way to go. There are plenty of videos on youttube showing you how to maximise UVs across objects.

Grant Abbit has some good videos on baking and uvs: