Secret Realm Generations (secret_realm_generation_type)
secret_realm_generation_type
The generation of a secret realm picks a generation type from this family to decide how the instance dimension is built. A data pack can only pick an existing type and cannot add new ones.
The registry entries a generation names (stem, dimension_type, biome) are resolved when an instance is created: datapack registries load in parallel, so what is read at decode time may not be bound yet. A failed resolution fails the creation (GENERATION_FAILED) and logs one line; no half-built instance is left behind.
"generation": { "type": "mxt:void", "biome": "minecraft:the_void", "dimension_type": "minecraft:the_end" }
mxt:stem
Takes one registered dimension generator as its template and opens an instance under a new dimension key.
| Field | Type | Default | Description |
|---|---|---|---|
stem | Dimension generator id | required | For example minecraft:overworld, minecraft:the_end. |
{ "type": "mxt:stem", "stem": "minecraft:the_end" }
mxt:flat
A superflat world.
| Field | Type | Default | Description |
|---|---|---|---|
preset | String | required | A vanilla superflat layer string, for example "1*minecraft:bedrock,2*minecraft:dirt,minecraft:grass_block;minecraft:plains". |
dimension_type | Dimension type id | minecraft:overworld | Which dimension type the instance uses. |
structures | Boolean | true | Whether to generate structures. |
{ "type": "mxt:flat", "preset": "1*minecraft:bedrock,2*minecraft:dirt,minecraft:grass_block;minecraft:plains" }
mxt:void
An empty world: no layers, one biome and no structures by default, which suits a secret realm furnished entirely from structures.
| Field | Type | Default | Description |
|---|---|---|---|
biome | Biome id | minecraft:the_void | The biome the whole instance uses. |
dimension_type | Dimension type id | none | Which dimension type the instance uses. |
structures | Boolean | false | Whether to generate structures. |
{ "type": "mxt:void", "biome": "minecraft:the_void", "dimension_type": "minecraft:the_end" }
mxt:template
Copies region, entities and poi from <server directory>/mxt_secret_realm/<template>/ and then loads them; this is the route for a hand-built map.
| Field | Type | Default | Description |
|---|---|---|---|
template | String | required | The template directory name; only [A-Za-z0-9_-]+ is accepted, and anything else fails the creation. |
stem | Dimension generator id | required | The dimension generator used to load this template. |
{ "type": "mxt:template", "template": "trial_arena", "stem": "minecraft:overworld" }
mxt:existing
Creates no dimension at all and uses one that already exists (including a datapack dimension/ entry). max_instances is meaningless for it, and the secret realm never unloads or deletes that dimension when an instance ends.
| Field | Type | Default | Description |
|---|---|---|---|
dimension | Dimension id | required | Uses this existing dimension as the instance directly. |
{ "type": "mxt:existing", "dimension": "minecraft:the_end" }
The border belongs to this type as well: it is the only one that touches that real dimension's border when a border is written, while every other type explicitly sets a freshly created dimension to the vanilla default border.