为什么这段代码运行的时候点击部件会出现错误?

Question

我运行这段代码的时候，点击部件就会出现
Uncaught TypeError: Cannot read properties of undefined (reading 'position')at VertexEnumerator.js:87:28
这样的错误

const options = {
    env: "AutodeskProduction",
    api: "derivativeV2",
    getAccessToken: (callback) => {
        fetch("http://localhost:8080/api/auth/token")
            .then((response) => response.json())
            .then((json) => {
                const auth = json.access_token;
                callback(auth, 3600);
            });
    },
    language: 'en'

};
Autodesk.Viewing.Initializer(options, () => {
    const urn = "dXJuOmFkc2sub2JqZWN0czpvcy5vYmplY3Q6ZmRzaGZqc19mZHNrZmxzal8xMjM0NTY2Ni8lRTQlQkElOTQlRTglQkQlQjQlRTYlOTYlOUMlRTclQkElQkYlRTYlQTglQTElRTUlOUUlOEIlMjB2My5mM2Q";
    let htmlDiv = document.getElementById("MyViewerDiv");
    viewer = new Autodesk.Viewing.GuiViewer3D(htmlDiv);
    viewer.start();
    loadModel(urn);

});
let loadModel = (urn) => {
    return new Promise((resolve, reject) => {
        function onDocumentLoadSuccess(doc) {
            const node = doc.getRoot().getDefaultGeometry();
            viewer.loadDocumentNode(doc, node).then(() => {
                viewer.addEventListener(
                    Autodesk.Viewing.GEOMETRY_LOADED_EVENT,
                    setupModelInteraction
                );
            });
            resolve();
        }
        Autodesk.Viewing.Document.load("urn:" + urn, onDocumentLoadSuccess, reject);
    });
};
const getModelNodeIds = (names, tree) => {
    const nodeIds = {};
    names.forEach(name => {
        nodeIds[`${name}NodeId`] = findNodeIdbyName(name, tree);
    });
    return nodeIds;
};

const setupModelInteraction = () => {
    const partNames = ["T1", "X1", "Z1", "Z2"];
    let tree = viewer.model.getData().instanceTree;
    let nodeIds = getModelNodeIds(partNames, tree);
    console.log(nodeIds)
    setUpPiovt(nodeIds, tree)
}
const setUpPiovt = (nodeIds, tree) => {
    baseRodPivot(nodeIds.T1NodeId, tree)
}


const baseRodPivot = (ID_BaseRod, tree) => {
    let Pivot_BaseRod = new THREE.Mesh(new THREE.BoxGeometry(5, 5, 5), new THREE.MeshBasicMaterial({ color: 0xff0000 }));
    let Position_BaseRod = getFragmentWorldMatrixByNodeId(ID_BaseRod, tree).matrix[0].getPosition().clone();
    Pivot_BaseRod.position.x = Position_BaseRod.x;
    Pivot_BaseRod.position.y = Position_BaseRod.y;
    Pivot_BaseRod.position.z = Position_BaseRod.z;
    viewer.impl.scene.add(Pivot_BaseRod);
}

Answer 1

1.Position_BaseRod 不存在时，赋值必然失败.
2.Position_BaseRod 存在， 但没有position属性 先给position赋值

Pivot_BaseRod.position = {};
Pivot_BaseRod.position.x = Position_BaseRod.x;
Pivot_BaseRod.position.y = Position_BaseRod.y;
Pivot_BaseRod.position.z = Position_BaseRod.z;

Answer 2

经过调试后，我把 viewer.impl.scene.add(Pivot_BaseRod);这句代码删掉，就没有出现这个错误了，具体原因我也不清楚