Eli5: How can games like minecraft or no mans sky be essentially infinite, yet take up a very small amount of storage?

Question

No mans sky is like 18GB or so on my PS4, yet there are 256 galaxies and literally around 18 quintillion planets. It can be played completely offline too, so it isnt coming from some server somewhere

I understand they’re procedurally generated, so they dont even exist until you pass through that area, but even after playing for countless hours and crossing thousands of miles of landmass, the save file is still extremely small

In: 1323

Answer 1

You don’t need to save everything that was generated. You only need to save what was CHANGED.

In minecraft if you have the seed everything will be exactly the same no matter how many different people load that seed so the only amount of data you need to save is the seed.

The only important bits that need to be saved are the blocks you changed. When you do this a lot the save files can start becoming very large as is the case with some of the very old minecraft servers that have absolutely insane save file sizes.