I don't get why you feel the need to resort to personal attacks / character assassination, no one is attacking you, you don't need to fight and you can change your opinion on something, no one is going to think less or more of you for it, you seem to have set yourself up as the opposition of caves and you must do everything in your power to make sure your side wins, but there is no winning / losing in this as this is not a debate, it is just a discussion on a ways to implement caves in Elite Dangerous.Oh dear, oh deary deary me.......
They don't "STORE" the planets they are proceduarally generated using a key derived from the data supplied by the stellar forge, every time a player enters a system the planets are generated from this data, it all happens live, even the key is never stored but generated again every time a player jumps into a system, that's why making changes to the Stellar Forge can potentially change every system in the galaxy. It's never actually "stored" anywhere! I mean really? Here you are proposing a "cave system" and you don't even understand how they generate the planets?
And how many of those random signal sources are bugged, with hatches buried under the ground and objects floating and concealed by rocks. A lot of them, but they are small objects so they only need a small flat area and they don't in any way interact with the planet height map, well except for sometimes poking through it and being inaccessible! The same with plants and other objects like fumaroles and the surface rocks, they are sometimes often bugged, floating and sometimes buried, invisible as well. Be fun right, having a floating cave entrance!
Until a player enters a system and the seed is first run no-one knows what is in that system, not even FDEV. This is procedural generation, the fact you are only now asking that means you have been making suggestions for caves the entire time with zero understanding of how the planets are actually generated, so maybe you don't actually have an easy way to put caves onto planets.
Regardless thank you for confirming what I first thought it was a set of parameters with a set seed, I was thinking it had to be this way otherwise the amount of data stored would be fairly significate, I am impressed on how quickly they are able to generate them on the fly.
Anyway after further thinking, caves may not need to be permanent as I first thought and could use the same system they use to place other points of interest, I had initially discarded this idea when it first came to me as I thought they would try to this kind of stuff as permanent features, but I have since remembered that some of the points of interest have buildings, something that is in fact not temporary but implemented in such a way, so I see no reason why caves can't be done the same way, and if you need an in-game law reason why a cave will exist one day but not the next, well tectonics plate shifts / earthquakes
Ah, the old dungeon master's trick of generating cave systems.
Hey if it works why change it? good systems be good systems