Make More Mob Cages Spawn

Question

I am playing in a minecraft world, and there seem to be very few mob spawners. I know it is possible to customize this setting in the world creator, but I would rather not

A. Lose all my progress, or
B. Worldedit my entire base into a new world

I have an NBT editor, would it be possible to change the setting from that and purge outer chunks so that they regenerate?

Answer 1

After doing some digging, and creating a new custom world to make comparisons with, I have found the tag that must be changed.

1. Download and install an NBT editor. (I used NBTExplorer.)
2. Head to your .minecraft install folder.

3. Open your saves folder, then the world you want to edit.

   

4. Open the "level.dat" file with the NBT editor you got previously.

   

5. Open the data section
   

   

6. About halfway down the screen there will be a tag for "generatorOptions"

7. Open the tag value and insert the following, (noting that if you have custom generated a world, this tag may already have a value):

{"useDungeons":true,"dungeonChance":**X**"}

Note the X; The X is how many times per chunk the game will try to make a mob cage/spawner. The default is 7.

8. Then make sure to save, and do keep in mind that this will only apply to newly loaded chunks.