Update app.py

app.py

@@ -712,7 +712,7 @@ async(c, o, p, d, n, m, s)=>{
           y = parseInt(evt.clientY - evt.target.getBoundingClientRect().y);
           
           if (Math.abs(x-xold)>16 || Math.abs(y-yold)>16) {
-            if (Math.abs(BABYLON.Engine.LastCreatedScene.activeCamera.radius - r_old) > 1/16) {
+            if (Math.abs(BABYLON.Engine.LastCreatedScene.activeCamera.radius) > 16) {
               BABYLON.Engine.LastCreatedScene.activeCamera.radius = r_old;
             } else {
               r_old = BABYLON.Engine.LastCreatedScene.activeCamera.radius;