使用 ARKit，加载 3D 对象不会锚定到特定的经纬度位置

如何解决使用 ARKit，加载 3D 对象不会锚定到特定的经纬度位置

我尝试了 Apple ARGeotracking 来加载房屋的 3D 模型。我提供了纬度和经度位置，以便在该特定位置加载对象。但是该对象并未锚定到特定的经纬度位置。此外，对象往往会随着用户的移动而移动。

水平面检测代码

 // Create a new AR Scene View.
        sceneView = ARSCNView(frame: view.bounds)
        sceneView.delegate = self
        // Show statistics such as fps and timing information
        sceneView.showsStatistics = true
        view.addSubview(sceneView)
  
        //configure scene view session to detect horizontal planes
        let configuration = ARWorldTrackingConfiguration()
        configuration.planeDetection = .horizontal
        sceneView.session.run(configuration)
        
        //uncomment to see feature points
        sceneView.debugOptions = [ARSCNDebugOptions.showFeaturePoints]

// 响应用户点击 AR 视图。

 @objc
    func handleTapOnARView(_ sender: UITapGestureRecognizer) {
     
        addGeoAnchor(at: projectLocation2D)

    }

添加 ARGeoAnchor 并在参数中提供纬度位置

//MARK:- 添加土工锚

func addGeoAnchor(at location: CLLocationCoordinate2D,altitude: CLLocationDistance? = nil) {
    var geoAnchor: ARGeoAnchor!
    if let altitude = altitude {
        geoAnchor = ARGeoAnchor(coordinate: location,altitude: altitude)
    } else {
        geoAnchor = ARGeoAnchor(coordinate: location)
    }
    addGeoAnchor(geoAnchor)
}


func addGeoAnchor(_ geoAnchor: ARGeoAnchor) {
    
    // Don't add a geo anchor if Core Location isn't sure yet where the user is.
    guard isGeoTrackingLocalized else {
        alertUser(withTitle: "Cannot add geo anchor",message: "Unable to add geo anchor because geo tracking has not yet localized.")
        return
    }
    arView.session.add(anchor: geoAnchor)
}



var isGeoTrackingLocalized: Bool {
    if let status = arView.session.currentFrame?.geoTrackingStatus,status.state == .localized {
        return true
    }
    return false
}

func distanceFromDevice(_ coordinate: CLLocationCoordinate2D) -> Double {
    if let devicePosition = locationManager.location?.coordinate {
        return MKMapPoint(coordinate).distance(to: MKMapPoint(devicePosition))
    } else {
        return 0
    }
}

// MARK: - ARSessionDelegate
func session(_ session: ARSession,didAdd anchors: [ARAnchor]) {
    for geoAnchor in anchors.compactMap({ $0 as? ARGeoAnchor }) {
        // Effect a spatial-based delay to avoid blocking the main thread.
        DispatchQueue.main.asyncAfter(deadline: .now() + (distanceFromDevice(geoAnchor.coordinate) / 10)) {
            // Add an AR placemark visualization for the geo anchor.
            self.arView.scene.addAnchor(Entity.placemarkEntity(for: geoAnchor))
        }
        
        // Add a visualization for the geo anchor in the map view.
        let anchorIndicator = AnchorIndicator(center: geoAnchor.coordinate)

        // Remember the geo anchor we just added
        let anchorInfo = GeoAnchorWithAssociatedData(geoAnchor: geoAnchor,mapOverlay: anchorIndicator)
        self.geoAnchors.append(anchorInfo)
    }
}

didAdd 锚点方法被调用，这里我提供了 url 来加载模型，因为我使用 EchoAR sdk 将模型加载到我们的应用程序中。模型加载但它没有锚定到特定的地理位置。这里 modelURL 的值来自我使用的 echoAR sdk。它以 .usdz 格式返回模型。

extension Entity {
    static func placemarkEntity(for arAnchor: ARAnchor) -> AnchorEntity {
        let placemarkAnchor = AnchorEntity(anchor: arAnchor)
        if modelURL != nil{
        let entity = (try? Entity.load(contentsOf: modelURL!))!
        placemarkAnchor.addChild(entity)
        }
        else{
            Utilities.sharedInstance.showError(message: "8C. ===Unable to render AR Model===")

        }
        return placemarkAnchor
    }
}