I want to know whenever Cesium automatically rebases it’s coordinates? Does Cesium fire a dispatcher or delegate whenever it rebases?
Cesium’s rebasing simply sets the UWorld’s OriginLocation property by calling SetNewWorldOrigin. And when that property changes, Unreal Engine itself calls ApplyWorldOffset on all AActors and UActorComponents in the level, so you can override that method to be notified. I’m not aware of a way to be notified of this from Blueprints (though it’s possible there is one and I simply haven’t found it), but if all else fails you can poll the Get World Origin Location | Unreal Engine Documentation from a Tick event or similar.