ARCore unity - Place objects between two objects

Question

Using ARCore on Unity, I'm trying to place one gameObject between two gameObjects. Unfortunately it doesn't display, it seems it is a problem with Anchor.

*Using Vuforia, i didn't had problem to position game objects.

What i try to achieve is:

1. Place two objects (A and B) on the ground when i touch the surface. It Works

2. Place a gameObject (C) between the two objects (A and B).Not displaying

   // Place target objects A and B on surface touch
   
   GameObject prefab;
   GameObject prefab2;
   prefab = AndyPointPrefab;
   prefab2 = AndyPlanePrefab;
   
   hitpoint= hitpoint + 1;
   
   // Place object A
   
   if (hitpoint==1){
   
     target1 = Instantiate(prefab, hit.Pose.position, hit.Pose.rotation);
     target1.transform.Rotate(0, k_ModelRotation, 0, Space.Self);
     var anchor = hit.Trackable.CreateAnchor(hit.Pose);
     target1.transform.parent = anchor.transform;
     mIsFirsttargetVisible=true;
   
   }
   else if (hitpoint==2){  // Place object B
   
    target2 = Instantiate(prefab2, hit.Pose.position, hit.Pose.rotation);
    target2.transform.Rotate(0, k_ModelRotation, 0, Space.Self);
    var anchor = hit.Trackable.CreateAnchor(hit.Pose);
    target2.transform.parent = anchor.transform;
    mIsSecondTargetVisible=true;
    hitpoint=-1;
   
   }
   
   //Update function : todisplay point C in-between.
   Update() {
   
   // Place object C
   
   if(mIsFirsttargetVisible && mIsSecondTargetVisible){
   GameObject objectMiddle = GameObject.CreatePrimitive(PrimitiveType.Sphere); 
   Vector3 middlePosition =  (target1.transform.position+target2.transform.position)/2;    
   objectMiddle.transform.position = middlePosition;
   objectMiddle.transform.localScale = new Vector3(200.0f, 10.0f, 200.0f);
   }
   }
   

EDIT

I successfully arrived to place the gameobject in between.

i added this last line in my code: target1.transform.parent = objectMiddle.transform;

 if(mIsFirsttargetVisible && mIsSecondTargetVisible){
    GameObject objectMiddle = GameObject.CreatePrimitive(PrimitiveType.Sphere); 
    Vector3 middlePosition =  (target1.transform.position+target2.transform.position)/2;    
    objectMiddle.transform.position = middlePosition;
    objectMiddle.transform.localScale = new Vector3(200.0f, 10.0f, 200.0f);
    target1.transform.parent = objectMiddle.transform;
    }