arfoundation-samples/Assets/Scripts/DisableVerticalPlanes.cs

using UnityEngine;
using UnityEngine.Experimental.XR;
using UnityEngine.UI;
using UnityEngine.XR.ARFoundation;

/// <summary>
/// This example demonstrates disabling vertical planes as they are
/// detected and instantiated by the <c>ARPlaneManager</c>.
/// </summary>
[RequireComponent(typeof(ARPlaneManager))]
public class DisableVerticalPlanes : MonoBehaviour
{
    [SerializeField]
    Text m_LogText;

    void OnEnable()
    {
        GetComponent<ARPlaneManager>().planeAdded += OnPlaneAdded;
    }

    void OnDisable()
    {
        GetComponent<ARPlaneManager>().planeAdded -= OnPlaneAdded;
    }

    void OnPlaneAdded(ARPlaneAddedEventArgs eventArgs)
    {
        var plane = eventArgs.plane;

        // Check whether the plane is a vertical plane.
        if (plane.boundedPlane.Alignment == PlaneAlignment.Vertical)
        {
            // Disable the entire GameObject.
            plane.gameObject.SetActive(false);

            // Add to our log so the user knows something happened.
            m_LogText.text += string.Format("\n{0}", plane.boundedPlane.Id);
        }
    }
}