SkinIO

[SimonBenAnderson]

Transfer Skin weights between assets that have different topology

UE Skin Transfer Investigation Result

[SimonBenAnderson]

Simple example code using the WeightModifier to zero out all weights to the root

void SetAllWeightsToRoot2(USkeletalMesh* SkeletalMesh)
{
    if (!SkeletalMesh)
    {
        UE_LOG(LogTemp, Error, TEXT("SkeletalMesh is null."));
        return;
    }
 
    const FReferenceSkeleton& RefSkeleton = SkeletalMesh->GetRefSkeleton();
    if (RefSkeleton.GetNum() == 0)
    {
        UE_LOG(LogTemp, Error, TEXT("SkeletalMesh has no bones."));
        return;
    }
 
    USkinWeightModifier* Modifier = NewObject<USkinWeightModifier>();
    Modifier->SetSkeletalMesh(SkeletalMesh);
 
    FName FirstBoneName = RefSkeleton.GetBoneName(0);
    TMap<FName, float> Weights = {{ FirstBoneName, 1.0f }};
 
    int32 NumVertices = Modifier->GetNumVertices();
    for (int32 Index = 0; Index < NumVertices; ++Index)
    {
        Modifier->SetVertexWeights(Index, Weights, true);
    }
 
    if (Modifier->CommitWeightsToSkeletalMesh())
    {
        SkeletalMesh->MarkPackageDirty();
        SkeletalMesh->PostEditChange();
        UE_LOG(LogTemp, Log, TEXT("Weights updated to first bone successfully."));
    }
    else
    {
        UE_LOG(LogTemp, Error, TEXT("Failed to commit skin weight changes."));
    }
}