问如何在查看器中添加多个模型？

EN

this.viewer.start(svfUrl, loadOptions, onLoadModelSuccess, onLoadModelError);
this.viewer.loadModel(svfUrl, loadOptions, onLoadModelSuccess, onLoadModelError); 

function loadModels(urns) {

    const viewerOptions = {
        env: 'AutodeskProduction',
        accessToken: token.access_token,
        extensions:[ ]
    };

    Autodesk.Viewing.Initializer(viewerOptions, () => {

        const div = document.getElementById('forgeViewer');
        viewer = new Autodesk.Viewing.Private.GuiViewer3D(div);
        viewer.start();
        urns.map((m)=>{
            Autodesk.Viewing.Document.load(`urn:${m.urn}`, (doc) => {
                var viewables = doc.getRoot().getDefaultGeometry();
                viewer.loadDocumentNode(doc, viewables,{
                    keepCurrentModels: true,
                })
                .then( onLoadFinished );
            });

        })
    });

    function onLoadFinished(doc) {
        console.log('loaded');
    }
}