This tutorial follows on from our other video, Using Poliigon textures in Maya with Arnold.
High quality textures are just the first part of creating realistic, believable materials. In the real world nothing is clean, even the most sterile environment will have imperfections and it's important to replicate that when creating realistic renders.
Create a new image texture node and load in the smudges texture (use the white smudges on a black background), be sure to click on override in the color space options so the gamma is set to 1.0.
Add in a color correction node and connect the texture to it, this will allow finer control once the setup is complete.
Add in an add node and feed in the original roughness map into the first input and then the smudges into the second.
Connect the add node to the roughness input of the Arnold shader.
Adjust scaling via the texture node and strength via the color correction node.
Create a new image texture node and load in the scratches texture (use the greyscale white scratches on a black background)), be sure to click on override in the color space options so the gamma is set to 1.0.
Add in a Bump 2D node and feed in the original normal map into the normal input and scratches texture into the bump_map input.
Adjust strength as required via the bump2d node.