Adobe Substance 3D's Wes McDermott, recognized for his excellent tutorials that we've featured multiple times on 80 Level, has showcased how the Compare Mask feature in Substance 3D Painter can be used to blend moss based on ambient occlusion.
This isn't the artist's first time sharing content based on Compare Masks. He utilized this feature to set up highly realistic floors with fallen leaves on top based on height and released a full video explaining how to create a denting effect: