UE4 has a "Specular" input, and Toolbag2 has an "Advanced Metalness" module which mimics the same thing. In both cases, specularity has a range of 0.00 - 0.08 and when no texture is applied, outputs a 50% grey (therefore, the final output without a map is 0.04). You can input a grayscale specular map into this, and when…