Just how hard is it to destroy a planet? Not that hard for a visual effects studio like Industrial Light Magic. The studio did the visual effects work for Rogue One, earning a well-deserved Best Visual Effects Oscar nomination for its trouble.
To show how they did it, ILM released an awesome reel showcasing scenes on Jedha and Scarif, where most of the destruction takes place. Each shot is broken down into different layers, with finer details added in different shots.
The shots start with a “beauty layer,†then a “gray renders + plate†is added to get some of the granular details added. After that, more beauty renders are added until the final shot is complete. This is an over-simplification of all the work that go into the shots; it is far more complicated work that takes months to complete.
Probably the most striking scene the video breaks down is the Death Star blast of Jedha. From the mountain silhouette to the eclipse-like Death Star and even the green beam that obliterates the planet, it’s gorgeous visual effects work.
Article source: https://www.technobuffalo.com/2017/02/19/rogue-one-vfx-reel-shows-how-entire-planets-are-destroyed/