May i suggest http://www.marmoset.co/toolbag Toolbag is great for making textures, it will auto update the files after you save so you can see your progress, Supports PBR spec or metalness. they also have a good page on how to use pbr http://www.marmoset.co/toolbag/learn/pbr-theory and an example http://www.marmoset.co/toolbag/learn/pbr-practice