Autodesk.Viewing.webVR无法加载

Question

无法加载webVR扩展程序。

代码：

var options = {
                "docid" : docs[0].path , 
                env : 'Development',
                extensions:[
                    'Autodesk.Viewing.webVR',
                ]
            };
            var viewercon = document.getElementById('viewercon');
            viewer = new Autodesk.Viewing.Private.GuiViewer3D(viewercon, {}});
            Autodesk.Viewing.Initializer(options,function(){
                    viewer.initialize () ;
                    viewer.loadModel (options.docid) ;
            });

viewer3D.js版本2.12