可以使用ARAnchor中的ARPlaneAnchor和ARImageAnchor来选择真实世界的平面或图像，将虚拟对象绑定到它们上面。

以下是绑定到平面的示例代码：

func renderer(_ renderer: SCNSceneRenderer, didAdd node: SCNNode, for anchor: ARAnchor) {
    guard let planeAnchor = anchor as? ARPlaneAnchor else { return }
    
    let plane = SCNPlane(width: CGFloat(planeAnchor.extent.x), height: CGFloat(planeAnchor.extent.z))
    let planeNode = SCNNode(geometry: plane)
    planeNode.position = SCNVector3Make(planeAnchor.center.x, 0, planeAnchor.center.z)
    planeNode.eulerAngles.x = -.pi / 2
    node.addChildNode(planeNode)
    
    let sphere = SCNSphere(radius: 0.1)
    let sphereNode = SCNNode(geometry: sphere)
    sphereNode.position = SCNVector3Make(planeAnchor.center.x, 0.1, planeAnchor.center.z)
    node.addChildNode(sphereNode)
}

以上代码在检测到ARPlaneAnchor时，在场景中添加一个平面节点和一个球形节点。可以根据需求添加更多节点和虚拟对象。

以下是绑定到图像的示例代码：

func renderer(_ renderer: SCNSceneRenderer, didAdd node: SCNNode, for anchor: ARAnchor) {
    guard let imageAnchor = anchor as? ARImageAnchor else { return }
    
    let plane = SCNPlane(width: imageAnchor.referenceImage.physicalSize.width, height: imageAnchor.referenceImage.physicalSize.height)
    plane.firstMaterial?.diffuse.contents = UIColor(red: 0, green: 1, blue: 0, alpha: 0.5)
    let planeNode = SCNNode(geometry: plane)
    planeNode.eulerAngles.x = -.pi / 2
    
    node.addChildNode(planeNode)
    
    let sphere = SCNSphere(radius: 0.1)
    let sphereNode = SCNNode(geometry: sphere)
    sphere