It will have some effect on performance, I tested with a few different scenes and while the transition occurred a few frames were dropped. But it wasn’t an unreasonable amount, and the only case where I saw very long frames was in a scene that was already quite heavy by itself. So I think if your scene isn’t very very heavy it will be fine. The if statement won’t be necessary as the setSize function already checks if the size has changed before running: Babylon.js/thinEngine.ts at f610f68b036265c9e0b50ddb27428c1370ec468a · BabylonJS/Babylon.js · GitHub