c++
for (int32 LOD = 0; LOD < ShapeLODCount; LOD++) {
    FMeshDescription* SourceMeshDescription = BasicShapeLib[NewShape]->GetMeshDescription(LOD);

    TVertexInstanceAttributesRef<FVector4f> VertexColors = SourceMeshDescription->VertexInstanceAttributes().GetAttributesRef<FVector4f>(MeshAttribute::VertexInstance::Color);
    for (const FVertexInstanceID& VertexInstanceID : SourceMeshDescription->VertexInstances().GetElementIDs())
    {
        // Get the current vertex color
        FVector4f CurrentColor = VertexColors[VertexInstanceID];
        FColor CurrentFColor = FColor(CurrentColor.X * 255, CurrentColor.Y * 255, CurrentColor.Z * 255, CurrentColor.W * 255);

        // Check if the vertex is red, we use RED as our default color.
        if (CurrentFColor == FColor::Red)
        {
            // Update to the new color
            VertexColors[VertexInstanceID] = FVector4f(NewColor.R / 255.0f, NewColor.G / 255.0f, NewColor.B / 255.0f, NewColor.A / 255.0f);
        }
    }

    FStaticMeshOperations::AppendMeshDescription(*SourceMeshDescription, *AllNewMeshDescriptions[LOD], AppendSettings);
}

c++
for (int32 LOD = 0; LOD < ShapeLODCount; LOD++) {
    FMeshDescription* SourceMeshDescription = BasicShapeLib[NewShape]->GetMeshDescription(LOD);

    TVertexInstanceAttributesRef<FVector4f> VertexColors = SourceMeshDescription->VertexInstanceAttributes().GetAttributesRef<FVector4f>(MeshAttribute::VertexInstance::Color);
    for (const FVertexInstanceID& VertexInstanceID : SourceMeshDescription->VertexInstances().GetElementIDs())
    {
        // Get the current vertex color
        FVector4f CurrentColor = VertexColors[VertexInstanceID];
        FColor CurrentFColor = FColor(CurrentColor.X * 255, CurrentColor.Y * 255, CurrentColor.Z * 255, CurrentColor.W * 255);

        // Check if the vertex is red, we use RED as our default color.
        if (CurrentFColor == FColor::Red)
        {
            // Update to the new color
            VertexColors[VertexInstanceID] = FVector4f(NewColor.R / 255.0f, NewColor.G / 255.0f, NewColor.B / 255.0f, NewColor.A / 255.0f);
        }
    }

    FStaticMeshOperations::AppendMeshDescription(*SourceMeshDescription, *AllNewMeshDescriptions[LOD], AppendSettings);
}