Hi All,
Sorry for the late reply, I posted this a couple of weeks ago and thought it was lost at sea. I’m glad there are responses and questions! As @and-rad stated the details must remain on the first UV channel because of the tangent base. I’m also using an iterative bump-offset (3 iterations) in this setup rather than POM because it ischeaper.
I wasn’t aware that DBuffer decals had gotten a hike in 4.20, but I still think that this workflow I’m describing has some advantages. Namely that the decals, the trims, and the tiling texture which holds the grunge are all contained within the same material and placed seamlessly with the edge damages and grime following your details. The below example is three objects referencing the same material, the only thing different is the UV0 channel and some cuts on the object to the right. There is also no opacity being referenced, which can be expensive all on its own.
To answer @ChrisCorr, Doing things this way is almost texel-density agnostic. You could build a tank with it or a gun and the trims/floaters would not look too big or small. The reason why is that the grunge is an entirely separate entity from the details. The edge wear and dirt are not baked in, rather a short set of shader instructions meant to mimic what you get with something like smart masks in Substance Designer. Those tend to use Cavity and AO which are threshold-blended with grunge so they are an important part of this setup. So I’m using Normal Map, ID Map, and Mask (AO, Cavity, Height). Even though there are a few shader instructions in total, it stays in the green.
In the bunker project I did recently, almost everything was made with one trim sheet and one grunge map (four image textures).
