ARPlacementInteractableSingle.cs

using System.Collections.Generic;
using UnityEngine;
using UnityEngine.XR.ARFoundation;
using UnityEngine.XR.ARSubsystems;
using UnityEngine.XR.Interaction.Toolkit.AR;

public class ARPlacementInteractableSingle : ARBaseGestureInteractable
{
    [SerializeField]
    [Tooltip("A GameObject to place when a raycast from a user touch hits a plane.")]
    public GameObject placementPrefab;

    [SerializeField]
    [Tooltip("Callback event executed after object is placed.")]
    private ARObjectPlacementEvent onObjectPlaced;

    private GameObject placementObject;
    
    private static List<ARRaycastHit> hits = new List<ARRaycastHit>();

    private static GameObject trackablesObject;

    protected override bool CanStartManipulationForGesture(TapGesture gesture)
    {
        if (gesture.StartPosition.IsPointOverUIObject())
            return false;

        // Allow for test planes
        if (gesture.TargetObject == null || gesture.TargetObject.layer == 9)
            return true;


        return false;
    }

    protected override void OnEndManipulation(TapGesture gesture)
    {
        if(Input.touchCount == 0)
        {
            return;
        }

        var touch = Input.GetTouch(0);
        var touchPosition = touch.position;
        bool isOverUI = touchPosition.IsPointOverUIObject();

        if (gesture.WasCancelled)
            return;

        // If gesture is targeting an existing object we are done.
        // Allow for test planes
        if (gesture.TargetObject != null && gesture.TargetObject.layer != 9)
            return;

        //Checking if touch is over UI element
        if (isOverUI)
        {
            Debug.Log("UI is touched");
        }

        Debug.Log(isOverUI);
        // if (!isOverUI && GestureTransformationUtility.Raycast(gesture.StartPosition, hits, TrackableType.PlaneWithinPolygon))
        // Raycast against the location the player touched to search for planes.
        if (GestureTransformationUtility.Raycast(gesture.StartPosition, hits, TrackableType.PlaneWithinPolygon))
        {
            var hit = hits[0];
            
            // Use hit pose and camera pose to check if hittest is from the
            // back of the plane, if it is, no need to create the anchor.
            if (Vector3.Dot(Camera.main.transform.position - hit.pose.position, hit.pose.rotation * Vector3.up) < 0)
                return;
            
            //if(placementObject == null)
            //{
                placementObject = Instantiate(placementPrefab, hit.pose.position, hit.pose.rotation);

                // Create anchor to track reference point and set it as the parent of placementObject.
                // TODO: this should update with a reference point for better tracking.
                var anchorObject = new GameObject("PlacementAnchor");
                anchorObject.transform.position = hit.pose.position;
                anchorObject.transform.rotation = hit.pose.rotation;
                placementObject.transform.parent = anchorObject.transform;

                // Find trackables object in scene and use that as parent
                if (trackablesObject == null)
                    trackablesObject = GameObject.Find("Trackables");
                if (trackablesObject != null)
                    anchorObject.transform.parent = trackablesObject.transform;

                onObjectPlaced?.Invoke(this, placementObject);
            //}
        }
    }
}

I am using version 5.0 of ARFoundation. There is a problem in this code which I am struggling to fix about where Raycasting occurs.

Assets/Scenes/ceiling/ARPlacementInteractableSingle.cs(65,13): warning CS0618: 'GestureTransformationUtility.Raycast(Vector2, List, TrackableType)' is obsolete: 'Raycast has been deprecated. Use Raycast with updated signature instead.'

this line (in my version, line 64 in yours):
if (GestureTransformationUtility.Raycast(gesture.StartPosition, hits, TrackableType.PlaneWithinPolygon))

how do I implement 'use raycast with updated signature instead'?

(BTW your code and video have been incredibly useful for solving some problems with the Unity documentation)

Hello could you solve this problem? I have the same too...

    if (GestureTransformationUtility.Raycast(gesture.startPosition, hits, xrOrigin, TrackableType.PlaneWithinPolygon)) 

this is supported format for updated raycast.

using UnityEngine.XR.Interaction.Toolkit.AR;
using UnityEngine;
using System.Collections.Generic;
using UnityEngine.XR.ARFoundation;
using UnityEngine.XR.ARSubsystems;

public class Singleplacement : ARBaseGestureInteractable
{
[SerializeField]
private GameObject placementPrefab;

[SerializeField]
private ARObjectPlacementEvent onObjectPlaced;

private GameObject placementObject;
private static List<ARRaycastHit> hits = new List<ARRaycastHit>();
private static GameObject trackablesObject;

protected override bool CanStartManipulationForGesture(TapGesture gesture)
{
    if (gesture.targetObject == null)
    {
        return true;
    }
    return false;
}

protected override void OnEndManipulation(TapGesture gesture)
{
    if (gesture.targetObject != null)
    {
        return;
    }
    if (GestureTransformationUtility.Raycast(gesture.startPosition, hits, xrOrigin, TrackableType.PlaneWithinPolygon))
    {
        var hitPose = hits[0].pose;

        // Allow a new game object for AR placement object
        if (placementObject == null)
        {
            placementObject = PlaceObject(hitPose);

            onObjectPlaced?.Invoke(this, placementObject);
        }
    }
}

// Edited method to handle placement similar to ARPlacementInteractable
protected virtual GameObject PlaceObject(Pose pose)
{
    var placementObject = Instantiate(placementPrefab, pose.position, pose.rotation);

    // Create anchor to track reference point and set it as the parent of placementObject.
    var anchor = new GameObject("PlacementAnchor").transform;
    anchor.position = pose.position;
    anchor.rotation = pose.rotation;
    placementObject.transform.parent = anchor;

    // Use Trackables object in scene to use as parent
    var trackablesParent = xrOrigin != null
        ? xrOrigin.TrackablesParent
        : (xrOrigin != null ? xrOrigin.TrackablesParent : null);

    if (trackablesParent != null)
    {
        anchor.parent = trackablesParent;
    }

    return placementObject;
}

}
this is a working script for single prefab placement