Hi everyone,
I’ve run into a reproducible issue in Unreal Engine 5.5/5.6 when using the Path Tracer.
The problem:
The same meshes and materials render perfectly fine in Lumen and rasterization modes.
Any help, insights, or confirmation from others seeing the same would be greatly appreciated.
Thanks!
Can you screenshot your material setup for me? I am not getting this.
FixRotateAboutAxisNormals:
I also tried using world space normal, didn’t work either
(note the lighting is correct if the object don’t have any rotational offset, the closer it to original state the less artifact)
VAT material, I am using the “Vertex Animation Manager” plugin
the screenshot from the first post is the comparison with this material
Just checking back in on this — we’re still completely blocked by this Path Tracer normals issue in UE.
This isn’t just a curiosity for us — we have a production deadline and our necks are on the line if we can’t get reliable Path Tracer output with materials that adjust normals (e.g. FixRotateAboutAxisNormals / WPO).
If anyone from Epic or the community has insight, even confirmation that it’s a known bug, it would really help us plan next steps. Right now we don’t know if there’s a workaround or if we need to rethink our material setup entirely.
Appreciate any guidance — thanks in advance!
I just flagged it to the dev. He’s gonna have a look.
Ok the dev had a look and was able to make it a lot better. Its still not compeletely clean as we don’t have a clean split between the smooth shading normal and the normal-mapped shading normal in this case because the material applies both together. But its better. It will be in 5.7. If you build the engine I can send you a Git link to the changelist.
Awesome, it worked great — thanks a ton for checking it out and improving it!
