这是我在 Autodesk Forge 和 Javascript 中的第一个项目，所以我很迷茫。

这是我的代码：

async function loadHeatmaps(model){

            const dataVizExtn = await viewer.loadExtension("Autodesk.DataVisualization"); 

            // Given a model loaded from Forge
            const structureInfo = new Autodesk.DataVisualization.Core.ModelStructureInfo(model);
        
            const devices = [
                {
                    id: "Oficina 6", 
                    name:"Oficina-",
                    position: { x: 22.475382737884104, y: 7.4884431474006163, z: 3.0 }, 
                    sensorTypes: ["temperature", "humidity"]
                }
            ];

            var offset =  Autodesk.viewer.model.getGlobalOffset();      
            removeOffset(devices[0],offset)

            // Generates `SurfaceShadingData` after assigning each device to a room.
            
            const shadingData =  await Autodesk.structureInfo.generateSurfaceShadingData(devices);
            
            // Use the resulting shading data to generate heatmap from.
            await dataVizExtn.setupSurfaceShading(model, shadingData);

            // Register color stops for the heatmap. Along with the normalized sensor value
            // in the range of [0.0, 1.0], `renderSurfaceShading` will interpolate the final
            // heatmap color based on these specified colors.
            const sensorColors = [0x0000ff, 0x00ff00, 0xffff00, 0xff0000];

            // Set heatmap colors for temperature
            const sensorType = "temperature";
            dataVizExtn.registerSurfaceShadingColors(sensorType, sensorColors);

            // Function that provides sensor value in the range of [0.0, 1.0]

            function getSensorValue(surfaceShadingPoint, sensorType) {
            // The `SurfaceShadingPoint.id` property matches one of the identifiers passed
            // to `generateSurfaceShadingData` function. In our case above, this will either
            // be "cafeteria-entrace-01" or "cafeteria-exit-01".
            const deviceId = surfaceShadingPoint.id;

            // Read the sensor data, along with its possible value range
            let sensorValue = readSensorValue(deviceId, sensorType);
            const maxSensorValue = getMaxSensorValue(sensorType);
            const minSensorValue = getMinSensorValue(sensorType);

            // Normalize sensor value to [0, 1.0]
            sensorValue = (sensorValue - minSensorValue) / (maxSensorValue - minSensorValue);
            return clamp(sensorValue, 0.0, 1.0);
            }

            // This value can also be a room instead of a floor
            const floorName = "01 - Entry Level";
            dataVizExtn.renderSurfaceShading(floorName, sensorType, getSensorValue);
        } 

        var viewer;

        function view_document(token_id, urns, derivative) {
            var options = {
                env: 'AutodeskProduction',
                api: derivative, 
                getAccessToken: function(onTokenReady) {
                    var token = token_id; //token from authentification
                    var timeInSeconds = 3600; 
                    onTokenReady(token, timeInSeconds);
                }//input for viewer initializer function
            };

            Autodesk.Viewing.Initializer(options, function() {
                
                //fetch the forgeViewer id in the html
                var htmlDiv = document.getElementById('forgeViewer');

                //create the view at the html div
                viewer = new Autodesk.Viewing.GuiViewer3D(htmlDiv);

                //start viewer
                var startedCode = viewer.start();

                if (startedCode > 0) {
                    console.error('Failed to create a Viewer: WebGL not supported.');
                    return;
                }

                console.log('Initialization complete, loading a model next...');

                for (let i = 0; i < urns.length; i ++) {
                    Autodesk.Viewing.Document.load(urns[i]["urn"], (doc) => {
                        var viewables = doc.getRoot().getDefaultGeometry();
                        viewer.loadDocumentNode(doc, viewables,{
                            preserveView: false,
                            keepCurrentModels: true,
                            placementTransform: (new THREE.Matrix4()).setPosition(urns[i]["xform"]), keepCurrentModels: true,
                            globalOffset: {x:0,y:0,z:0}
                        })
                    });
                }
                loadHeatmaps(this.viewer.model);
                });

        }

它应该可以工作。我从一个教程网站复制了它，到处都看到过类似的代码。但是当我加载它时，日志控制台上会出现此错误： 控制台上的错误

DG_V2:162 未捕获（在承诺中）TypeError：无法读取未定义的属性（读取“模型”） 在 loadHeatmaps（DG_V2:162:35）

你能帮帮我吗？我感觉什么都行不通。使用模型、this.model、autodesk.model、autodesk.viewer.model 或任何其他类型的组合均不起作用，这让我抓狂...