Repository navigation
Feature World Type
Since: v0.16.0 — PR #20 — custom preset with raised y=32 floor
v0.18.0 — PR #24 — 11-option Floor Y dropdown on the World tab (−64, −48, −32, −16, 0, 16, 32, 48, 64, 80, 96); y=32 remains the default
v0.19.0 — PR #25 — preset is now default-selected when the Create World screen opens (via a client mixin into CreateWorldScreen.<init>)
post-v0.74.0 — PR #105 — adds Dungeon Train (Nether) and Dungeon Train (End) as two new entries in the World Type dropdown; the chosen preset determines which dimension the player and starter train spawn in on first login
v0.389.0 — PR #639 — removes Dungeon Train (Nether) and Dungeon Train (End) from the #minecraft:normal world-preset tag; new worlds can now only be created with an Overworld start. Existing Nether/End-start saves are unaffected — see Starting in the Nether or End below
Adds a custom world preset, Dungeon Train, selectable from the Create New World → More → World Type dropdown. It maps the overworld to a custom dimension whose floor sits at y=32 instead of vanilla's y=-64. Build height stays at y=320, so only the unused basement is removed — about 6 of 24 sub-chunk sections per chunk are eliminated.
For a train-on-rails game where players spend their time on the surface or aboard a moving Valkyrien Skies ship, the deep underground is wasted simulation. Removing it gives:
-
CPU: ~24% fewer noise samples per chunk-gen — the preset ships its own
noise_settingswithnoise.min_y=32, so the noise pipeline stops sampling discarded layers (not just the chunk dropping empty sections after the fact). - Disk + RAM: ~15-20% smaller region files; fewer non-empty sections in memory.
- Singleplayer → Create New World → More tab → World Type dropdown
- Cycle through to Dungeon Train and create the world
- Bedrock floor sits at y=32; everything above behaves like a vanilla overworld
For dedicated servers, set level-type=dungeontrain:dungeon_train in server.properties before first launch.
| Kept | Lost |
|---|---|
| Surface terrain (mountains, rivers, oceans) | Deepslate ore zone (y=-64..0) — including diamonds and ancient-debris-equivalent ores |
| Iron, coal, copper, redstone (surface ore zones) | Lush + dripstone caves below y=32 |
| All vanilla biomes (multi_noise) | Strongholds and mineshafts anchored below y=32 |
| Vanilla nether and end (unchanged) | A small amount of cave detail near the new floor — hidden by the bedrock layer |
PR #24 adds an 11-option Floor Y picker to the Create New World → World tab, visible only when the Dungeon Train preset is selected. The selection maps the world to one of eleven internal Y-variants at the moment the user clicks Create New World; the committed save then lives at the chosen floor height for its lifetime.
Dropdown options (multiples of 16):
| Y | World range | Use case |
|---|---|---|
| −64 | y=−64..320 | Vanilla height — keeps all deepslate/diamond, no perf gain |
| −48 | y=−48..320 | Clip the bottom 16 blocks of the deepslate zone |
| −32 | y=−32..320 | Keep most deepslate ores, mild perf gain |
| −16 | y=−16..320 | Keep top half of deepslate |
| 0 | y=0..320 | Keep surface ores only; sea-level floor |
| 16 | y=16..320 | Slightly above sea level |
| 32 (default) | y=32..320 | Shipped v0.16.0 default — ~24% chunk-gen savings |
| 48 | y=48..320 | Raised floor, preserves surface biome detail |
| 64 | y=64..320 | Sea-level-equivalent floor |
| 80 | y=80..320 | High floor, best perf |
| 96 | y=96..320 | Extreme — most aggressive perf gain, smallest world |
World top stays at y=320 for every option. Lower Y preserves more of the vanilla deepslate/diamond zone at the cost of chunk-gen savings; higher Y is cheaper but sacrifices ore layers.
Usage:
- Singleplayer → Create New World → World tab
- With World Type: Dungeon Train selected, the Floor Y row appears as a centered 150×20 CycleButton below Bonus Chest
- Click through to the desired Y
- Click Create New World
Dedicated servers: set level-type=dungeontrain:dungeon_train_y{N} (e.g. dungeontrain:dungeon_train_y0, dungeontrain:dungeon_train_y96) in server.properties before first launch. For the default y=32 use dungeontrain:dungeon_train (unchanged from v0.16.0).
The dropdown selection persists across Create-World screen entries within a single game launch, so re-opening the screen after a preset cycle restores the last chosen Y.
Starting in the Nether or End (PR #105)
⚠️ Removed from new-world creation in PR #639 (v0.389.0). The Dungeon Train (Nether) and Dungeon Train (End) entries no longer appear in the Create World screen's World Type cycle — new worlds can only be created with an Overworld start. This section is kept for reference and for anyone maintaining a world that already started in the Nether/End; the underlying mechanism below is otherwise unchanged and those saves keep working exactly as before.
Two additional World Type entries — Dungeon Train (Nether) and Dungeon Train (End) — started the player and the auto-spawned train in minecraft:the_nether or minecraft:the_end instead of the overworld. Worldgen for those dimensions is vanilla — only the starting dimension changes; the overworld is still configured exactly like the plain Dungeon Train preset (raised y=32 floor) and remains accessible via portals.
Usage (legacy — no longer reachable from the Create World UI):
- Singleplayer → Create New World → World tab
- Cycle the World Type button to one of:
-
Dungeon Train— start in overworld (default, and now the only UI-selectable option) -
Dungeon Train (Nether)— start in the Nether -
Dungeon Train (End)— start in the End
-
- Click Create New World — on first login the player is teleported to a random ground position alongside the train in the chosen dimension.
The Floor Y dropdown is hidden for the Nether/End presets (it only affects the overworld bedrock floor). The Dungeon Train Options… sub-screen still applies — Train Y, carriage dimensions, generation mode, and group size all work the same in any starting dimension.
Persistence: the chosen dimension is committed to dungeontrain_world.dat (the existing per-world SavedData) as a startingDimension NBT tag, defaulting to overworld for legacy worlds. This is why existing Nether/End-start saves are unaffected by the removal above — the preset files and the StartingDimension enum are all still in place; only the tag entry that made them reachable from a new Create World screen was removed.
Known limitations:
-
Death/respawn is a separate mechanism, partially restricted since.
StartingDimension.rollRespawnDimensionindependently rolled a fresh 94% Overworld / 5% Nether / 1% End dimension on every death. As of PR #643 (v0.390.0), the death screen's "New World"/"Same World" buttons (DeathScreenLayoutHandler, plus the dev-only/new-worldcommand which shares the same code path) always start the fresh save in the Overworld — they create a new world, so the same "Overworld by default" intent as this page applies. The vanilla in-place "Respawn" button (RespawnDimensionEvents) is intentionally unchanged and still rolls the 94/5/1 split, since it's a deliberate run-variance mechanic that doesn't create a new world. See Feature-Death-Screen-Buttons for the full mechanism. - Default Train Y (78) in the End places the train above the central island; in the Nether it sits well above the lava ocean and below the ceiling. Both can be overridden via the Dungeon Train Options sub-screen if the user wants a different elevation for that biome.
Dedicated servers: level-type=dungeontrain:dungeon_train_nether or dungeontrain:dungeon_train_end in server.properties still works for anyone who sets it explicitly (the preset registry entry still exists) — only the graphical World Type cycle button no longer surfaces these two options.
| File | Purpose |
|---|---|
data/dungeontrain/dimension_type/overworld.json |
Default DimensionType with min_y=32, height=288 (y=32 preset) |
data/dungeontrain/dimension_type/overworld_y{N}.json (10 files) |
Y-variant DimensionTypes; min_y=N, height=320-N
|
data/dungeontrain/worldgen/noise_settings/overworld.json |
Vanilla overworld noise_settings with noise.min_y=32, noise.height=288
|
data/dungeontrain/worldgen/noise_settings/overworld_y{N}.json (10 files) |
Y-variant noise_settings (only noise.min_y + noise.height differ) |
data/dungeontrain/worldgen/world_preset/dungeon_train.json |
Default preset (y=32); nether/end reference vanilla |
data/dungeontrain/worldgen/world_preset/dungeon_train_y{N}.json (10 files) |
Y-variant presets referencing the matching DimensionType + noise |
data/dungeontrain/worldgen/world_preset/dungeon_train_nether.json |
Same dimension config as dungeon_train.json; the preset ID is the marker that signals "start the player in the Nether" (PR #105) |
data/dungeontrain/worldgen/world_preset/dungeon_train_end.json |
Same shape as the Nether variant; signals "start in the End" (PR #105) |
data/minecraft/tags/worldgen/world_preset/normal.json |
Lists only dungeon_train as of v0.389.0 (PR #639) — dungeon_train_nether/dungeon_train_end were removed so the UI selector shows one entry; both preset files still exist and resolve by key for legacy saves + the death-screen carry-forward flow. Y-variants remain intentionally out of the tag (the registry resolves them by key instead) |
src/.../world/StartingDimension.java |
Enum mapping preset path → dimension ResourceKey<Level> and NBT id (PR #105) |
src/.../client/worldgen/PendingStartingDimension.java |
Client-side static holder (mirrors FloorYState); updated each tick from the current preset path; consumed once on integrated-server start (PR #105) |
assets/dungeontrain/lang/en_us.json |
generator.dungeontrain.dungeon_train* keys all resolve to "Dungeon Train" so the preset button label stays consistent; dungeontrain.floor_y.* keys for the widget label/value/tooltip |
src/.../mixin/CreateWorldScreenWorldTabMixin.java |
@Inject at <init> TAIL of CreateWorldScreen$WorldTab; appends the Floor-Y row at hardcoded row index 5 |
src/.../mixin/CreateWorldScreenMixin.java |
init TAIL resolves the 11 preset holders into FloorYState; tick HEAD toggles widget visibility + re-applies the chosen Y on transitions back onto the plain DT preset |
src/.../mixin/CreateWorldScreenAccessor.java |
@Accessor exposing the package-private uiState field |
src/.../client/worldgen/FloorYState.java |
Client-side static holder for selected Y + per-screen widget + preset-holder map |
-
Disk footprint: ships 10 near-identical copies of the 2,541-line
noise_settings/overworld.json(one per non-default Y), ~900 KB uncompressed. A refactor to dynamic runtime registration (approach b from the Gate 1 plan) is tracked as a follow-up if size becomes an issue. -
Preset cycling quirk: cycling the World Type button forward while a Y-variant is active falls back to the plain
dungeon_trainpreset (vanilla'svalues.indexOf(current)returns −1 when the Y-variant isn't in the selector list, so it resets to index 0). From there, one more forward-cycle reaches Default. Thetickhandler explicitly does not re-apply Y when the user has just cycled from one DT variant to another — only on transitions from a non-DT preset back onto DT. - Vanilla density functions still reference absolute Y, so the new floor may produce small swiss-cheese caves just above bedrock — visually hidden, no gameplay impact.
- Existing worlds are unaffected. Only new worlds created with the Dungeon Train preset get the raised floor. Vanilla saves continue to work normally. Worlds created with a non-default Y on v0.18.0+ require the mod at v0.18.0 or later to continue loading (normal mod-version behavior; no migration).