A world's maximum build height can be set using the
maxbuildheight element. Once a player tries to build past the set maximum build height, they will be prompted with a message stating that they can not build past the playing field.
A world's terrain generator can be modified to use a specific seed, world and/or whether the vanilla chunk generator is used. By default a new random seed is generated for each match, unless one is specified in the seed attribute.
When using the vanilla generator the default minecraft terrain generator will be used instead of generating null chunks.
The specific world generation rules such as flat worlds, etc., can be changed by editing the world's
level.dat file with a NBT editor. The
RandomSeed value in the level data file is not used.
Any chunks not in the world's
region/ folder will be generated according to the minecraft chunk generation rules. This means that only the terrain that you have modified needs to be saved with the world.
world="" attribute is used to specify the sub-folder that contains the map's
|A node defining properties for this world's generator.|
|The level data sub-folder to be used with this map.||Sub-folder Name|
|Specify if this world is uses the vanilla or null chunk generator.||true/false||false|
|This worlds generation seed.||String|
|Allow physics events, such as water flowing, before the match starts.||true/false||false|
Maps that are entirely indoors or underground can use the
internal attribute on the main map element
to prevent observers from accidentally teleporting on top of the map with the compass tool.
In order for this to work, the exterior of the map must be completely filled in with solid blocks,
all the way up to the maximum build height.
See Main Map Element