Autodesk Forge Viewer -始终显示标记

// 初始化 Forge Viewer
var viewer;
Autodesk.Viewing.Initializer({ env: 'Local' }, function() {
    viewer = new Autodesk.Viewing.GuiViewer3D(document.getElementById('viewer'));
    viewer.start();

    // 加载模型
    var documentId = 'urn:YOUR_URN_HERE';
    Autodesk.Viewing.Document.load(documentId, function(doc) {
        var viewables = doc.getRoot().getDefaultGeometry();
        viewer.loadDocumentNode(doc, viewables).then(function(result) {
            // 添加文本注释标记
            var markup3dExt = viewer.getExtension('Autodesk.Viewing.Markups3d');
            if (!markup3dExt) {
                markup3dExt = new Autodesk.Viewing.Extensions.Markups.Core.Markups3DExtension(viewer);
                viewer.loadExtension(markup3dExt);
            }
            var markup = new Autodesk.Viewing.Extensions.Markups.Core.Markup3D();
            markup.set(
                new THREE.Vector3(0, 0, 0), // 标记位置
                new THREE.Vector3(1, 1, 1), // 标记大小
                'Hello, Forge Viewer!'       // 标记文本
            );
            markup3dExt.addMarkup(markup);
        });
    });
});