Dataless Mutable Crash (UnrealConversionUtils.cpp)

Development Character & Animation
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1

In our main project, when compiling a Customizable Object (CO_Character) that includes a SkeletalMeshParameter, I get this crash:

Assertion failed: ElementSize * (FirstVertexIndex + VertexCount) <= (int32)SkinBuffer->GetVertexDataSize() [File:D:\build\++UE5\Sync\Engine\Plugins\Mutable\Source\CustomizableObject\Private\MuCO\UnrealConversionUtils.cpp] [Line: 1219]

Screenshot and log are attached.

The strange thing is, I migrated this exact Customizable Object with all dependencies (mesh, materials, skeleton) to a new project, and it compiles without any issues. That is why unfortunately, I can’t provide a repo which is actually crashing.

Skinning the whole mesh only to one bone also makes compilation work.

Transferring skin weights from a backup of that mesh breaks it again.

Any idea what might be wrong with our mesh/skeleton/project? Thanks in advance!

2

I think the problem is the project setting r.GPUSkin.UnlimitedBoneInfluences=True

after disabling it, it compiled. however, metahuman face is complaining about it now: [Image Removed]what should I do?

3

Hey there,

I’m working on a repro for this at the moment, but as a quick test, could you turn on AllowCPUAccess on all of your skeletal meshes that are being run through Mutable while keeping the GPU skinning on?

Dustin

4

Hi Matthias,

Skeletal Mesh Parameter conversion is missing the code to convert meshes with unlimited bone influences. I’ll add it ASAP.

Pere