How do Minecraft seeds work?

Question

I am completely new to Minecraft. Where can I learn more about how Minecraft's so-called "seeds" work?

(I imagine the Minecraft "world" as a cellular automaton, and the "seed" as an somehow encoded initial configuration from which by certain rules an initial scenery is calculated. But this is most probably not the (whole) truth.)

See: http://en.wikipedia.org/wiki/Random_seed – Private Pansy Dec 28 '14 at 00:38 — Private Pansy, Dec 28 '14 at 00:38

score 1 · Answer 1 · answered Dec 28 '14 at 00:35

If you do some research about pseudorandom generators (like rand() in c++), you'll find that they need to be seeded (with srand(some number) in c++).

With the same seed, considering the implementation meaningless, they are guaranteed to give the exact same numbers...

score 1 · Answer 2 · edited Jan 08 '24 at 11:09

When you create a world, a seed is chosen. You can type in one yourself to be used, or leave it blank to use the current system time:

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The string you type is converted into an integer, which is why, even if you put a seed with letters in it, it'll always appear as a number in game with F3 or /seed.

This seed is then used for all of Minecraft's pseudorandom calculations in generating the level. These functions take the seed, then map it to a seemingly random value, but always the same value.

Unlike a cellular automaton, because of the random function, the input seed has no real relation to the output level. "1234" and "1235" will not produce similar levels, and there's no patterns like "lots of 5's give you jungles", although it may be by chance that "5555" spawns you in a jungle.

You can learn more about seeds on the wiki page:

https://minecraft.wiki/w/Seed_(level_generation)

How do Minecraft seeds work?

2 Answers2