Today I got some totally overblown areas when using a material for a braided cable sleeve. When I was looking a bit deeper into the issue I realized that it only occured when these three things came together:
a) The material has anisotropic reflections
b) The material uses the sheen layer
c) The material is lit by a Rectangle Light with a Directional value between (roughly) 0.5 and 0.8, but maybe that depends on the size and distance of the light as well.
I tried to isolate / emphasize the issue in this little scene.
It’s not pretty, but you’ll see what I mean when you play around with the Directional value of the light and the materials’ anisotropy value.
I expected to find these overexposed artifacts on the specular or sheen layer, but they sit on the lighting render element and have a riduculous brightness value.
In the end I could simply deactivate sheen in my initial scene, so it’s not really crucial. But I was wondering what this is… Me doing stupid things???
