how to modify vertex normals in skeletal mesh at runtime?

Development Programming & Scripting
1

hello, is there a way to modify vertex normals in skeletal mesh at runtime? I use SetVertexTangents(i, FVector(1, 0, 0), FVector(0, 1, 0), FVector(0, 0, 1)), but it not work, anyone helps me? thanks. my code is as below:
void ComputeNormals(USkeletalMesh *Mesh) {
// ExecuteOnRenderThread(&, this {
FSkeletalMeshLODRenderData *Model = &Mesh->GetResourceForRendering()->LODRenderData[0];

int32 ModelVertNum = Model->StaticVertexBuffers.PositionVertexBuffer.GetNumVertices();

TArray Positions;
TArray Triangles;
TArray uvs;

for (int32 i = 0; i < ModelVertNum; i++) {
Positions.Add(Model->StaticVertexBuffers.PositionVertexBuffer.VertexPosition(i));
uvs.Add(Model->StaticVertexBuffers.StaticMeshVertexBuffer.GetVertexUV(i, 0));
}

FRawStaticIndexBuffer16or32Interface &indexBuffer = *(Model->MultiSizeIndexContainer.GetIndexBuffer());

for (int32 i = 0; i < indexBuffer.Num(); i += 3) {
Triangles.Add(indexBuffer.Get(i));
Triangles.Add(indexBuffer.Get(i + 1));
Triangles.Add(indexBuffer.Get(i + 2));
}
TArray OutNormals;
TArray OutTangents;
UKismetProceduralMeshLibrary::CalculateTangentsForMesh(Positions, Triangles, uvs, OutNormals, OutTangents);

for (int32 i = 0; i < ModelVertNum; i++) {

FVector TanX = OutTangents[i].TangentX;
FPackedNormal TangentZ = OutNormals[i];
int a = 255;
TangentZ.Vector.W = (int8)a;
FVector TanZ = TangentZ.ToFVector();

FVector TanY = (TanZ ^ TanX) * ((float)TangentZ.Vector.W / 127.5f - 1.0f);

// Model->StaticVertexBuffers.StaticMeshVertexBuffer.SetVertexTangents(i, TanX, TanY, OutNormals[i]);

Model->StaticVertexBuffers.StaticMeshVertexBuffer.SetVertexTangents(i, FVector(1, 0, 0), FVector(0, 1, 0), FVector(0, 0, 1));

}

// Model->StaticVertexBuffers.StaticMeshVertexBuffer.InitRHI();

BeginUpdateResourceRHI(&Model->StaticVertexBuffers.StaticMeshVertexBuffer);
// });
}

I change normal to an strange odd value，but behavior is alway natural，confused