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.

The world="" attribute is used to specify the sub-folder that contains the map’s region/ and level.dat files. This is used with conditionals to automatically load the holiday versions of the map, etc.

Element Description
<terrain/> A node defining properties for this world's generator.
Terrain Attributes
Attribute Description Value Default
world The level data sub-folder to be used with this map. Sub-folder Name
vanilla Specify if this world is uses the vanilla or null chunk generator. true/false false
seed This worlds generation seed. String
pre-match-physics Allow physics events, such as water flowing, before the match starts. true/false false
<terrain vanilla="true" seed="qwerty"/>

<!-- Christmas world conditional -->
<if christmas="true">
    <terrain world="christmas"/>
<if christmas="false">
    <terrain world="normal"/>

Internal Maps

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