Update app.py

app.py

@@ -367,7 +367,7 @@ with gr.Blocks(css=css) as demo:
             canvas = gr.HTML(value="""<a href='#' onclick=\"
               var cntxt = document.getElementsByClassName('model3D')[0].getElementsByTagName('canvas')[0].getContext('webgl2');
               this.innerText = cntxt;
-              BABYLON.Tools.CreateScreenshot(BABYLON.Engine, BABYLON.Engine.LastCreatedScene.activeCamera, {forceDownload: false, precision: 1.0, (durl) => {
+              BABYLON.Tools.CreateScreenshot(BABYLON.Engine.LastCreatedScene.getEngine(), BABYLON.Engine.LastCreatedScene.activeCamera, {forceDownload: false, precision: 1.0, (durl) => {
                 document.getElementById('img_out').src = durl;
               }});
             \">webgl2</a><br/><img src='' id='img_out'/>""")