Introducing Roughness maps

Roughness maps, as the name suggests, are images used to control the level of roughness on different parts of a texture. Lower levels of roughness will lead to a glossier object. Adjusting this property with a roughness map can have a significant impact on the level of realism of a material, as not all parts of a material always have the same level of roughness. Figure 4.4 shows the Roughness map corresponding to the Albedo map from Figure 4.1.

Figure 4.4 – A Roughness map for a brick texture

As you can see, the Roughness map looks just like the Albedo map, except it is black and white. To understand how a roughness map works, let’s view the Roughness slider in the Principled BSDF node, shown in Figure 4.5.

Figure 4.5 – Roughness slider in the Principled BSDF node

To control the roughness of a material, we only need to give Blender a single numerical value between 0.000 and 1...