Yea, I knew it would be "as clear as mud" LOL! That's why I crave a video tut on how to do it. I'm an old dog trying to learn new tricks. I need a step by step way to adding textures to my models and then exporting into flight sim. Doug, you're right on target and my frustration(?) comes from the myriad of videos on how to texture a model, but nothing (yet) specifically for FSX / P3D. I can already build them really good AND I have successfully exported them also into FSX / P3D4&5 using Blender 2.79, but again, I'm trying to learn Blender 2.8 / 2.9. The "devils" in the details "they" always say, and texturing is where the models come to life. Any chance to improve on that is a bonus!
If you have already exported, etc into FSX /P3D, then you have tackled that part. Improving the models along with texture creation is key for you at this time. The differences between the previous versions and the current version of Blender (besides the look of) is basically the location of certain functions. After a while, it can be 2nd nature. It took me a while to adjust to the changes as well.
As far as how I "used" to do it, was simply UV mapping onto the model in Blender then exporting it. I used to use Paint Shop Pro, now Photoshop. I have not "baked", (wasn't sure what that was until recently), nor have I done anything other than apply the texture to the model in UV Mapping then exporting. They always came out pretty good (in my opinion) and some of them are very detailed with struts for rafters (using alpha channels to show ONLY the rafters...) etc. I know the world is evolving, and I want to evolve with it. (Speaking of that, is there any advantage to PBR on buildings / hangars?)
Sounds like you are a lot farther along than you think, lol. To answer your question on the advantages of PBR, I can only suggest more reading for you. LOL. A lot of people have asked the very same question and to be honest, it really comes down to their meaning of "advantages of". For instance, "are PBRs easy to create?", "I don't understand them.", "I'm not sure they are necessary, so why should I bother?", or "should I use PBRs on simple buildings or hangars?". This really depends on what you, the developer wants. This is really like, "Should I use Normal/ Bumps maps or not?". There are advantages to each workflow, Specular, and PBR. If they are done correctly, there should not be any or very little difference between the 2 of them. Also, comes down to the shader used within the Sim, which one has been better designed or programmed within (I'm not speculating or suggesting which has been either.
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The tutorials/ articles that I have been giving people to read are:
"Theory of Physically Based Rendering" By Jeff Russell. Dry reading to some but explains what PBRs are.
"Physically-Based Rendering And You Can Too!" By Joe Wilson.
"PBR Texture Conversion" By Joe Wilson.
These tutorials/ articles go far beyond what FS or the Sim expects. They will use maps or textures that FS or the Sim developer may know by another name or don't use but explains the use of very well.
EDIT: PBRs can be done through a number of applications, such as Quixel (pay), Substance Painter (Pay),
Materialize v1.78 (Free), and
ArmorPaint (Pay)