Thanks @theluthier! The “Alpha Texture” definitively needs to be adjusted in order to avoid the card-like look. And the feathers are still too glossy what makes them distinguishable from the underlying body texture. Getting this all right is really tricky since there’re many settings and therefore many occasions to do it wrong 😉.
I’m also not sure whether the “Anisotropic Shader” in Blender 2.90 is working the same way as the one in Blender 2.66.1 since your Piero’s fur feathers are looking much better than my Piero’s fur feathers despite the same settings. Another point is the “Displacement Input Socket” of the “Material Output Node” (grey in Blender 2.661, violet in Blender 2.90; thanks to @spikeyxxx for the hint!) for the modeled feathers which now needs a “Displacement Node” where I plug the “Bump Texture” into the “Height Input”. I’m wondering whether I should use the “Principled Hair Node” for the fur feathers.
