First of all, Fallout dont support one of the common PBR workflows. It wont use glossy/spec nor metal/rough, it is more like metal/glossy. I am not sure about your setup. You use specular in your map setup, but the pbr materials are based on metal/roughness. I am not sure if you could take full advantage of the pbr materials. Anyway, specular is wrong, because it is nearly the same as the metalness map did. If you paint everything by hand, and make no usage of the material or smartmaterials its ok how you work. As far as i see. Fallout works with glossy/spec in the _s map. But you cant work with glossy/spec PBR. You have to work with metal/roughness and use the metalmap as specular for you export. But metalness is no longer for metal only and black and white / yes or no. It depends on the speculary of your material now. So it could be gray, too. And it is possible you have to darken your metal material color. Fallout dont support correct PBR color values for metal. Sure, your viewport material could be wrong in Substance Painter. Not sure if there is a correct shader for this. But for ingame it works. Export options are easy. Basecolor and Normalmap (OGL) as usual, For the _s Put the metallic into the red chanel and the Glossy (from the converted maps) into the green chanel. After that, I get this result. In Substance Painter http://www2.pic-upload.de/thumb/29043272/SpPipboy2.jpg And here Ingame http://www2.pic-upload.de/thumb/29043268/PipMG.jpg Maybe i am wrong, but thats how you could take full advantage of Substance Painter. Thats all what i see from my testings with Substance Painter.