Lightmass crash: "Static mesh element count did not match mesh instance count!"

Development Rendering
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1

This error seems to have popped up out of nowhere (was running fine, then suddenly not) when attempting to build my lighting.

=== Lightmass crashed ===
Assertion failed: StaticMesh->GetLOD(GetMeshLODIndex()).NumElements == MaterialElements.Num() [File:D:\Build++UE4\Sync\Engine\Source\Programs\UnrealLightmass\Private\Lighting\StaticMesh.cpp] [Line: 277]
Static mesh element count did not match mesh instance count!

Running a geometry build doesn’t reveal any errors.

I can’t seem to figure out what the heck is causing it… any ideas on what it’s talking about, and how I might go about fixing it?

Thanks!

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2

Solution was found here, under a different but similar error.

3

Hello Brittnell! I have the same problem, but it is not solved with the Swarm Agent! What can be? Thank you!

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4

In case anyone has this issue and cant find an answer like I could not, to the “Static mesh element count did not match mesh instance count!” I figured out a solution. Hopefully this helps someone.

I accidentally auto generated an LOD so low, that it had 0 triangles, must have moved a decimal point. Anyway, once I re-did that LOD so it had some triangles, it worked perfectly.