I am loading .babylon objects from a server that are very heavy:
1- I want to add a po pup before loading these objects
2- the zoom +/- with the mouse wheel will be automatically reversible after a big zoom + / - : I want to stop it (I want to block this change).
You can also use an assetsManager and display a progress bar in HTML, as an overlay, according to the meshes being loaded. After all of them are loaded you hide the overlay.