Ok here’s the thing from what i gathered so far:
To keep you in the loop, I got a few responses from Epic, one is in this thread posted by another person running into a similar issue, the others are by mail and answerhub.
For the record we are talking about skinned moving skeletal meshes and not static ones.
My first problem (eyelid shades) had in fact to do with normals of the mesh and there is a workflow for it that i’ve tried before but epic guys presented it in a step by step procedure in max which solved that problem after i tried it again, its in answerhub.
The second problem the facets is still a problem: this thing has very little to do with the topology of the mesh, it has however to do with lighting and detailed shadows in UE and from what i also heard that there is still an ongoing side issue with normals and tangents inside unreal after the recent updates which may not be helping and is being looked into to be hopefully resolved in the future. I don’t know for sure if this has anything to do with my current problem or if it will reduce it. Because on the surface without knowing the shadow map contribution to this problem it would definitely look like a normals issue gone wrong that’s why it was my first impression, but its more complicated than that apparently.
The problem will not be immediately visible with unreal’s default lighting scenarios or indirect lighting (such as in your scene), however it will be visible under a directional light with detailed shadows, by this i mean trying to achieve high fidelity shadows on surface detail such as nose and hair strips casting detailed shadows on the face and themselves, for that, shadow cascades and dyn moving distance needs to be modified on the light and when you do this apparently the shadow map itself and the nature of it in engines will effect and bring about artifacts on the surface of the mesh. sort of like the bias settings and how that could introduce artifacts, (for the record i always leave this on default settings) and my shadow map res is set high 4K for now.
I’m still trying to understand it all and the why and the how are still lurking somewhere in my brain : ), but i’ve been hinted at these culprits along with the questionable normals issue on the side that has been reported.
So i went back and brought down my cascades to default settings and started tweaking other settings in the light to get similar results, but in the end i didn’t solve the artifact. it is still there but i brought it down a little.
That’s as far as i’m at for now. So try your scene under moving or stationary directional light with lets say dynamic shadow cascades set to 6 and moving distance adjusted to as best as possible according to a close up camera. You will most likely see these artifacts pop up. you may even leave the shadow cascades to 3 and try just with the moving distance until you get detailed shadows the artifacts will pop up. Also make sure they are skeletal meshes. if you don’t have time feel free to upload your mesh and i can show you what i mean.
The whole thing is about trying to get detailed shadows on characters and faces without these artifacts.