实际做法

点击某界面，通过其OnPointerDown（IPointerDownHandler）获得的eventData.position，生成射线进行检测。

 Ray ray = Camera.main.ScreenPointToRay(eventData.position);
 Physics.Raycast(ray, out RaycastHit hit)

完整代码

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.EventSystems;

public class ClickObjTest : MonoBehaviour, IPointerDownHandler, IPointerUpHandler
{
    public void OnPointerDown(PointerEventData eventData)
    {
        Ray ray = Camera.main.ScreenPointToRay(eventData.position);
        if (Physics.Raycast(ray, out RaycastHit hit))
        {
            // TODO:针对hit提供的信息做相应处理
        }
    }

    public void OnPointerUp(PointerEventData eventData)
    {
       
    }
}