"Normal Texture Coordinates" for Creation of Eyeball Veinlets

I've just done some experiments in order to better understand why the "Normal Texture Coordinates" work so well with the creation of eyball veinlets. I haven't found a satisfying explanation so far but what I can say is that "Normal Texture Coordinates" obviously introduce more variation by reflecting the mesh's topology as is can be demonstrated with the "Triangle Fan" of a default "UV Sphere":

1) Object Texture Coordinates


2) Normal Texture Coordinates


  • Ingmar Franz(duerer) replied

    "Normal Texture Coordinates" furthermore introduce a significant contrast between darker and brighter areas as a kind of filter on top of the "Texture" itself (Note: This is only a visual but no technical description!):