I was wondering if it is possible make such effect in current PBR model. here's the link to the scratchmap and the tutorial I've tried but it looks uniform and too blurry in 2048:
Imo this should be dealt with an anisotropic shader. Take a look at the wiki page, maybe you can find something there: http://wiki.polycount.com/wiki/Anisotropic_map btw.. this effect and pbr don't have anything to do with each other. People tend to think pbr is some now technology or so.
it seems that UE4 doesn't support anisotropic maps yet - https://answers.unrealengine.com/questions/10648/undefined.html UE3 had it though. And if it can be done through anisotropic maps only then no PBR needed indeed.