tap to place an object in spatial mapping is not working, below is my code

using UnityEngine;

public class TapToPlaceParent : MonoBehaviour { bool placing = false; private GameObject Stage;

 // Called by GazeGestureManager when the user performs a Select gesture
 void OnSelect()
 {
     // On each Select gesture, toggle whether the user is in placing mode.
     placing = !placing;

     // If the user is in placing mode, display the spatial mapping mesh.
     if (placing)
     {
         SpatialMapping.Instance.DrawVisualMeshes = true;
     }
     // If the user is not in placing mode, hide the spatial mapping mesh.
     else
     {
         SpatialMapping.Instance.DrawVisualMeshes = false;
     }
 }

 // Update is called once per frame
 void Update()
 {
     // If the user is in placing mode,
     // update the placement to match the user's gaze.

     if (placing)
     {
         // Do a raycast into the world that will only hit the Spatial Mapping mesh.
         var headPosition = Camera.main.transform.position;
         var gazeDirection = Camera.main.transform.forward;

         RaycastHit hitInfo;
         if (Physics.Raycast(headPosition, gazeDirection, out hitInfo,
             30.0f, SpatialMapping.PhysicsRaycastMask))
         {
             // Move this object's parent object to
             // where the raycast hit the Spatial Mapping mesh.
             this.transform.parent.position = hitInfo.point;
             gameObject.transform.parent.position = hitInfo.point;

             // Rotate this object's parent object to face the user.
             Quaternion toQuat = Camera.main.transform.localRotation;
             toQuat.x = 0;
             toQuat.z = 0;
             this.transform.parent.rotation = toQuat;
             gameObject.transform.parent.rotation = toQuat;
         }
     }
 }

}