Deforming a mesh embedded in the flesh Component

[sameerkarjatkar]

I have FleshAsset which is embedded inside a skeletal mesh component . My target is to deform the mesh by some velocity when the user clicks on the Asset on the viewport . For that I take the mouse cooordinates and find the FleshAsset under it . I also find the Vertices that overlap the impact point .I applied deformations on the vertices but they are not visible on the viewport . Following is my code snippet

USkeletalMeshComponent pComponent = Cast(HitResult.GetComponent());
if (!pComponent)
return;
AActor FleshOwner = pComponent->GetOwner();
if (!FleshOwner)
{
return ;
}

TArray<UFleshComponent*> Components;
FleshOwner->GetComponents(UFleshComponent::StaticClass(), Components);
for (UActorComponent* Component : Components)
{
UFleshComponent* FleshComponent = Cast(Component);
FleshComponent->bAllowAnyoneToDestroyMe = true;
FleshComponent->bHasPerInstanceHitProxies = true;
FleshComponent->bRayTracingFarField = true;
FleshComponent->SetCollisionEnabled(ECollisionEnabled::QueryAndProbe);
if (FleshComponent && FleshComponent->IsAttachedTo(pComponent))
{
UFleshAsset* fleshAsset = const_cast<UFleshAsset*>(FleshComponent->GetRestCollection());
UDeformableTetrahedralComponent *pDefTetComp = Cast(FleshComponent);

    if (!pDefTetComp)
    {
 
       UE_LOG(LogTemp, Log, TEXT("DeformableTetrahedralComponent is Empty"));
    }
    else
    {
        pDefTetComp->RegisterComponent();
    }

    UStaticMesh* StaticMesh = fleshAsset->StaticMesh.Get();
    UBodySetup* BodySetup =  StaticMesh->GetBodySetup();
    if (BodySetup)
    {
        BodySetup->Modify();
        BodySetup->InvalidatePhysicsData();
        BodySetup->MarkPackageDirty();
        FTransform ComponentTransform = FleshComponent->GetComponentTransform();
        FleshComponent->SetSimulatePhysics(true);
        FKAggregateGeom& AggGeom = BodySetup->AggGeom;
        for (int32 i = 0; i < AggGeom.ConvexElems.Num(); ++i)
        {
            FKConvexElem& ConvexElem = AggGeom.ConvexElems[i];
            TArray<FVector> & tVertices = ConvexElem.VertexData;
            TArray<int32> Indices = ConvexElem.IndexData;
            for (int32 Index = 0; Index < Indices.Num(); Index += 3)
            {
                if (Index + 2 < Indices.Num())
                {
                    FVector Vertex1 = ComponentTransform.TransformPosition(tVertices[Indices[Index]]);
                    FVector Vertex2 = ComponentTransform.TransformPosition(tVertices[Indices[Index + 1]]);
                    FVector Vertex3 = ComponentTransform.TransformPosition(tVertices[Indices[Index + 2]]);

                    UE_LOG(LogTemp, Log, TEXT("Face vertices: %s, %s, %s"), *Vertex1.ToString(), *Vertex2.ToString(), *Vertex3.ToString());

                    if (PointInTriangle(HitResult.ImpactPoint, Vertex1, Vertex2, Vertex3))
                    {
                        UE_LOG(LogTemp, Log, TEXT("Impact point lies on face with vertices: %s, %s, %s"), *Vertex1.ToString(), *Vertex2.ToString(), *Vertex3.ToString());
                        float DeformStrength = 100.0f;
                        FVector DeformDirection = (Vertex1 - HitResult.ImpactPoint).GetSafeNormal();
                        Vertex1 += DeformDirection * DeformStrength;
                        DeformDirection = (Vertex2 - HitResult.ImpactPoint).GetSafeNormal();
                        Vertex2 += DeformDirection * DeformStrength;
                        DeformDirection = (Vertex3 - HitResult.ImpactPoint).GetSafeNormal();
                        Vertex3 += DeformDirection * DeformStrength;
                        // Update the vertices back to local space
                        tVertices[Indices[Index]] = ComponentTransform.InverseTransformPosition(Vertex1);
                        tVertices[Indices[Index + 1]] = ComponentTransform.InverseTransformPosition(Vertex2);
                        tVertices[Indices[Index + 2]] = ComponentTransform.InverseTransformPosition(Vertex3);
                        pDefTetComp->AddVelocityChangeImpulseAtLocation(DeformDirection, HitResult.ImpactPoint);
     
                   }
               }
           }
        }
        ConvexElem.ComputeChaosConvexIndices(true);
        ConvexElem.SetCollisionEnabled(ECollisionEnabled::QueryAndPhysics);
        BodySetup->CreatePhysicsMeshes();
        FleshComponent->RecreatePhysicsState();
        FleshComponent->MarkRenderStateDirty();
        StaticMesh->Build();
  
   }