Import mesh that has custom normals that face away from their original plane normal significantly.
look at the mesh at an angle such the mesh is between the camera and the sun
System Information:
AMD Ryzen 3 2200G, 16GB, Radeon RX 570
Expected Behavior
I expect my mesh to have rounded normals and respond to light correctly
Actual Behavior
the normals that are facing towards the sun start to glow from what i assume is an “unclamped” shining effect
this is further amplified using pbr materials that have higher roughness (which should be doing the opposite effect of dampening the gloss on the object)
demonstration:
tree normals viewed in blender, represented by the purple vectors
this issue happens to most tree meshes that use a similar normal transfer technique in other live games as well
another model i noticed this issue on was the forest pack officially released by roblox
Issue Area: Engine Issue Type: Display Impact: High Frequency: Constantlyi
Could we get an update for this request? It’s almost been a year now and It’s still affecting every single game that uses foliage with modified normals, even the big front page ones, It’s been a major roadblock for my environments and I’m sure many other artists as well
As a different pov, some UGC accessories appear to use this bug to create cool lighting effects on their accessories, so fixing this issue without a toggle of some form (or legacy support) would unfortunately break such UGC accessories.
Thank you for submitting this. An engineer from the rendering team took a look at this and determined that this is an artifact of how our lighting system was designed and that it would require a new material for foliage with Fresnel tuned down to address this.
More technical info:
The bright white highlight observed by the user is Fresnel reflection that is a part of our BRDF. Under ordinary conditions, it is bright only at grazing angles, when the surface is almost parallel to the light. But out-of-whack normals exaggerate the effect on random polygons in the mesh. It is further compounded by overlapping with specular reflection, which produces very bright pixel values.
To address the issue, it requires a separate BRDF (i.e. a new material) specifically for foliage with Fresnel toned down.
