I tried to assign different materials to face - they work correctly only on Eevee rendering. enter image description here When I tried to render using Cycles - the surface always black - doesn't matter what the material or base color, only 2 properties have value - Emission and Alpha, they work correctly, face orientation is ok on this face.

enter image description here

And the blend file

  • $\begingroup$ I guess your environment (World) is just a color, hence no reflections... $\endgroup$
    – brockmann
    Apr 19, 2020 at 11:52
  • $\begingroup$ @brockmann yes, it is. But I already tried to change the world color to different colors - no effect on this face. It also correctly affects other facets, but not his one. $\endgroup$
    – Ashen One
    Apr 19, 2020 at 11:56
  • $\begingroup$ @brockmann no effect even with hdri. $\endgroup$
    – Ashen One
    Apr 19, 2020 at 12:04
  • $\begingroup$ @brockmann mb it is because I use Blender 2.9 alpha and It's a bug? Okay, let me try stable version. $\endgroup$
    – Ashen One
    Apr 19, 2020 at 12:05
  • $\begingroup$ @brockmann added blend file $\endgroup$
    – Ashen One
    Apr 19, 2020 at 12:12

1 Answer 1


The mesh has custom split normals in the problematic area. In order to see the split normals, switch to edit mode and enable Display Split Normals in the Viewport Overlays.

Viewport Overlays

View split normals

Problematic Normals

Problematic normals

If you have created the split normals intentionally you can edit them until they match the desired result (consult the manual for ways to edit normals). In case the custom split normals were created by accident and you don't want them, they can be deleted in Object Data Properties > Geometry Data > Clear Custom Split Normals Data.

Clear custom split normals

Clear custom split normals

Fixed Normals

Fixed normals

When custom split normals are stored, Auto Smooth is automatically enabled. It can be disabled in Object Data Properties > Normals > Auto Smooth, in case you don't need it.

Disable Auto Smooth

Disable Auto Smooth


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