Minecraft 1.3 adds the option of selecting a "seed" when creating a new world.
Many people don't know what a seed is, so this is a super short and simple explanation:
In order to generate random* numbers, computers use a "random number generator" (RNG). The RNG is a mathematical function that will cycle through a (very) large list of numbers in a chaotic order. The "seed" of this function can be thought as the starting point of this list.
So every time you start the RNG, you need to give it a seed number, so it can begin picking numbers from the chaotic list mentioned above. (Think of the RNG as a shuffled deck of cards, each seed is one way that the deck can be shuffled - and every time you draw cards, they will come in the same order).
What does this mean in practice?
When minecraft generates a world, it makes many random decisions (biomes, heigh, types of blocks, positions of ores), which are ruled by picking random numbers from the RNG. If you start the RNG with the same seed, it will (well, should) generate the exact same world**, every time.
EDIT: A little more info about what seeds do and don´t affect in minecraft:
- They DO affect the entire world topography (even non-yet created chunks)
- They DON´T affect spawn coordinates (using the same seed will create the same world, but with different spawn coordinates
- TO TEST: Do seeds affect plant creation?
TL;DR: You can share the seed of a cool world to give it to other people without having to send them your save.
* - random numbers generated by computers aren't really random, but this is a very nerdy subject ** - since the world is generated on the fly (more world is generated as people explore), the unexplored part of the world will be generated differently by different people. Only the area generated before you begin playing will be the same (unless Minecraft has a separate RNG for world generation and saves its state, that would be cool, but complicated). Seems I was wrong about this. Great! :-D
So is there a way to find the seed used for a world we generated randomly without one?
Or is the idea to put a random string of numbers into the seed box and have that as the seed in the event that we want to share it?
You say that using the same seed will only give you the same starting terrain, not the same map overall, but that doesn't make sense. The whole world should be deterministically generated from a single seed, it seems to me. That's why world saves are so comparatively small when the number of blocks are taken in to account. The terrain generation is 100% deterministic, so the save only needs to contain the seed and the changes that have been made to the proceedurally generated landscape in order to be able to completely reconstruct the terrain. Can you better explain why only the starting area would be the same?
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Quote from Adam222 »
So, yeah. Minecraft is kind of like walking into a high-class auction with top security and a solid reputation only to find out that everyone else in the room is a mugger. Who explodes.
Me and a few people from /v/ managed to confirm that seeds give you the same terrain, but not the same spawn.
We tested this by generating a world and giving the spawn coordinates of the the first generation, as well as general landmarks. Upon generating more worlds with the same seed, we had different spawns, but everyone was able to find the coordinates given in the first generation, which matched the landmarks. A few even spawned just a few blocks away from the initial spawn.
Can you better explain why only the starting area would be the same?
Depends on how the use of the RNG is implemented. It could be different if the same RNG was used both for world generation on demand, and mob generation. Then you could change the period of the RNG by forcing mobs to spawn (by staying near a dark cave during day, or lighting grass at night), or by preventing them from spawning in a similar way. It is like drawing more cards from that deck, so that you will have a different value when you draw the next one.
However, by the previous reports, it seems that this is not the case, either the world generation and mob controller have different RNGs, or indeed the world is entirely generated from the get go like you said. Anyway, way to go, Notch!
9634581020001 will create a very nice landscape with overhanging terrain, open lava lake near spawn...
I found a red mushroom there as well.
This is an amazing world!
Not just the lava lake, but the two mountain halves are epic!
I'm going to build a floating island city starting from in between the two halves!
you sire get a
EDIT: Next to a red mushroom there was a lot of clay!!!
No, placing/destroying blocks shouldn't effect future chunk generation.
And no, seeds don't effect spawn location, according to what people are reporting. Spawns seem to be placed randomly with no connection to the map seed.
Rollback Post to RevisionRollBack
Quote from Adam222 »
So, yeah. Minecraft is kind of like walking into a high-class auction with top security and a solid reputation only to find out that everyone else in the room is a mugger. Who explodes.
This is great, should be stickied...but first, make a guide telling us how to find the seed of a world we already have. Also, what does effect the spawn point then? A different random number?
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Quote from Ultra-Orange »
Quote from Direwolf20 »
#37) Ores tend to spawn in packs
If you take one out you better be ready to take on its angry cousins!
Took out an over head coal node once and was snuffed by a gang of Gravel seeking revenge!
This is great, should be stickied...but first, make a guide telling us how to find the seed of a world we already have. Also, what does effect the spawn point then? A different random number?
That's what it seems to be. I'd also be interested for someone to confirm that trees, flowers, etc don't generate from the seed either. From what I've read of people decompiling and analyzing the code, that seems like it would be right, but I don't really know. That would also explain why chunks that haven't been edited from world gen would have non-0 save size.
Rollback Post to RevisionRollBack
Quote from Adam222 »
So, yeah. Minecraft is kind of like walking into a high-class auction with top security and a solid reputation only to find out that everyone else in the room is a mugger. Who explodes.
Would be epic........ if MINECRAFT FRICKEN WORKED!!!
Minecraft actually works. It's linked to your forum account. Whenever you don't understand what Beta means, more hours are added to the jar launcher's troll timer.
Many people don't know what a seed is, so this is a super short and simple explanation:
In order to generate random* numbers, computers use a "random number generator" (RNG). The RNG is a mathematical function that will cycle through a (very) large list of numbers in a chaotic order. The "seed" of this function can be thought as the starting point of this list.
So every time you start the RNG, you need to give it a seed number, so it can begin picking numbers from the chaotic list mentioned above. (Think of the RNG as a shuffled deck of cards, each seed is one way that the deck can be shuffled - and every time you draw cards, they will come in the same order).
What does this mean in practice?
When minecraft generates a world, it makes many random decisions (biomes, heigh, types of blocks, positions of ores), which are ruled by picking random numbers from the RNG. If you start the RNG with the same seed, it will (well, should) generate the exact same world**, every time.
EDIT: A little more info about what seeds do and don´t affect in minecraft:
- They DO affect the entire world topography (even non-yet created chunks)
- They DON´T affect spawn coordinates (using the same seed will create the same world, but with different spawn coordinates
- TO TEST: Do seeds affect plant creation?
TL;DR: You can share the seed of a cool world to give it to other people without having to send them your save.
* - random numbers generated by computers aren't really random, but this is a very nerdy subject
** - since the world is generated on the fly (more world is generated as people explore), the unexplored part of the world will be generated differently by different people. Only the area generated before you begin playing will be the same (unless Minecraft has a separate RNG for world generation and saves its state, that would be cool, but complicated).Seems I was wrong about this. Great! :-DOr is the idea to put a random string of numbers into the seed box and have that as the seed in the event that we want to share it?
We tested this by generating a world and giving the spawn coordinates of the the first generation, as well as general landmarks. Upon generating more worlds with the same seed, we had different spawns, but everyone was able to find the coordinates given in the first generation, which matched the landmarks. A few even spawned just a few blocks away from the initial spawn.
thanks for the seed man, also, the waterfall into the lava lake was epic
Depends on how the use of the RNG is implemented. It could be different if the same RNG was used both for world generation on demand, and mob generation. Then you could change the period of the RNG by forcing mobs to spawn (by staying near a dark cave during day, or lighting grass at night), or by preventing them from spawning in a similar way. It is like drawing more cards from that deck, so that you will have a different value when you draw the next one.
However, by the previous reports, it seems that this is not the case, either the world generation and mob controller have different RNGs, or indeed the world is entirely generated from the get go like you said. Anyway, way to go, Notch!
This is an amazing world!
Not just the lava lake, but the two mountain halves are epic!
I'm going to build a floating island city starting from in between the two halves!
you sire get a
EDIT: Next to a red mushroom there was a lot of clay!!!
And no, seeds don't effect spawn location, according to what people are reporting. Spawns seem to be placed randomly with no connection to the map seed.
That's what it seems to be. I'd also be interested for someone to confirm that trees, flowers, etc don't generate from the seed either. From what I've read of people decompiling and analyzing the code, that seems like it would be right, but I don't really know. That would also explain why chunks that haven't been edited from world gen would have non-0 save size.
Minecraft actually works. It's linked to your forum account. Whenever you don't understand what Beta means, more hours are added to the jar launcher's troll timer.
^^Five seconds from you will make my day