This tutorial follows on from our other video, Using Poliigon textures in 3DS Max with Redshift.
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 redshift bitmap node and load in the smudges texture (use the white smudges on a black background), be sure to click on override in the node settings and make sure the gamma is set to 1.0.
Add in a RGB Multiply and connect the texture to the top input, this will allow finer control once the setup is complete.
Add in a Composite node and feed in the original roughness map into the layer1 input and then the smudges into the layer2.
Connect the composite node to the roughness input of the Redshift shader.
Adjust scaling via the texture node and strength via the multiply node.
Create a new redshift image node and load in the scratches texture (use the greyscale white scratches on a black background)), be sure to click on override in the node settings and make sure the gamma is set to 1.0.
Create a new bump map node and connect the scratches texture to it.
Create a bump blender node and connect the original normal map into the base input and the scratches bump map into the layer0 input. Then feed the output of the bump blender into the bump map input of the Redshift shader.
Adjust strength as required via the bump blender layer controls.