Made my own ShaderBall where the UV is not made for painting on, but for help defining coordinates and aniso tangent space. It’s low poly with subdiv, and I can’t fix some of the stretching errors, particularly when trying to maintain direction. UV has overlaps and not suitable for painting or baking. Ball is basic, the base has some protrusions for SSS tests, a plane with wrong normal (in case I need to account for that), and two thin boxes in the back for SSS estimation and backlighting experiments (strong area light behind). Basic HDR for main lighting.
ShaderBall_AnisoGGX - GGX is fine on its own if you want long stretching on metals with some visible roughness.
ShaderBall_AnisoBechman+GGX - is required if you want a high polish appearance while being able to stretch strong lights (here, the sun). Only GGX doesn’t work at all. Mix factor is 0.01 Beckman. Beckman is 1.5 roughness and 1.0 aniso, where aniso direction is modulated with a stretched voronoi to produce ±0.001 variation. Color and roughness is fixed, and only a bevel node for normals. The GGX can be pretty much whatever.
ShaderBall_Cast - Some kind of cast appearance. The basic idea is using a dense Voronoi/Cells to generate random colors, which is then used to modify normals directly (going through a some stuff that also does normalize). Similar to how you would do carpaint flakes and snow glitter I guess. A “grease topcoat” on top which uses a reduced impact version of the same normals. Nothing fancy.