Mirrored Mesh Turns Dark After Harvesting Instances in UE5

[Kaydo007]

Hi everyone,

I imported two identical cube meshes from SketchUp into Unreal Engine 5 using Datasmith. In SketchUp, I grouped a cube, copied it, and mirrored it to face the original. Once imported into UE5, both cubes appeared fine.

However, when I used “Harvest Instances” on the mesh to optimize performance, the mirrored copy turned completely dark or black. It looks like a lighting or shading issue, possibly related to negative scaling from the mirror operation.

Has anyone faced this issue with mirrored geometry?
Is there a way to fix the lighting problem on the mirrored instance after harvesting? Or should I avoid mirroring like this before importing?

Any advice or workflow recommendations would be greatly appreciated!

Thanks!

[Kaydo007]

I solved it, i just needed to enable Nanite for the mesh, now it’s perfect

[OohWowow]

can you give a little more insight on what you mean be “enable nanite on the mesh”? I am running into the same issues at the moment in UEFN.

UEFN report here: Mirrored Static Meshes Break Lighting When Converted to Instances - General / Issues and Bug Reporting - Epic Developer Community Forums

[Kaydo007]

Open the mesh and in the details panel click on (enable nanite) and apply changes, or in the content browser right click on the mesh and click (enable nanite)