>>297686741
What's the specular and roughness textures look like? Unity's specular standard shader uses the RGB channels of the specular texture for color, and the alpha channel for smoothness (aka roughness). https://docs.unity3d.com/2018.4/Documentation/Manual/StandardShaderMaterialParameterSpecular.html If your "roughness" texture is a single channel or greyscale texture you might need to combine it as the alpha channel to the specular texture.