Hi, I’ve been experimenting with custom vertex normals lately. Unfortunately it seems like cycles produces unsatisfactory results when rendering these, especially the more glossy the material is.
Have a look at the images below(go to the full res, it’s 3k in width)
The issue should be obvious in the fourth image, the cycles render. There’s a sudden, dark gradient at the edges. I’ve also added the three passes where the issue appears: glossy direct, glossy indirect and ao.
This seems to be related to cylces doing raytracing, as none of these issues exist in the viewport, the blender render, unity or unreal.
It’s happening with light sources, as well as with (only) environment lighing. I tried tweaking various light and render settings and different methods to do the custom normals. All without success. They look great everywhere except in cycles with glossy materials.
I wonder if other raytracers have the same problem? I’ve tested in substance painter’s iray (only environment lighting) where it is not happening(or maybe very very slightly, barely noticeable).
I currently don’t have access to any other renderers. If you have access to vray, octane, keyshot or whatever else people use these days and want to test, I’ve attached my test cube as well(cycles_and_FWVNs.fbx.zip).
Any input on this is appreciated. I have no problem recompiling blender with some tweak or some patch, if that is what it takes, I just need the tweaks and patches as that is beyond what I can do
cycles_and_FWVNs.fbx.zip (6.21 KB)