the gui objects are not found nor the arcRotate camera and if you look at the inspector, there is no node anymore, only the camera created before loading the scene.
About the GUI elements, currently they aren’t exported in the .babylon format.
As for the camera, I’ve checked the generated .babylon file and it is there What was happening is that when you use SceneLoader.Load, this function creates an entirely new scene, which wasn’t the same one being returned in the createScene function. You would use this Load even before creating your scene, like in this example: Blender to Babylon.js exporter | Babylon.js Documentation.
In the case you want to add the elements of a .babylon file to an preexisting scene, like the one created on the playground, you want to use the SceneLoader.Append function, like I’m doing here in this updated version of your playground: https://playground.babylonjs.com/#67VZ89#3. You can see that I pass the existing scene as an argument to the Append function, and also a callback to run once it’s ready.
For your GUI elements you can save to the snippet server or save to JSON separately from the Scene. The GUI editor can be used to modify and save changes to your gui.