World Height: Y320+

A Hytale server early plugin that removes the hardcoded 320-block world height limit, allowing fully functional worlds up to 32,736 blocks tall — the maximum the engine supports.

What it does

Hytale's server has the world height hardcoded at 320 blocks (10 sections × 32 blocks) across 43 server classes — chunk storage, collision, physics, spawning, world generation, NPC AI, block interactions, and more.

This plugin intercepts class loading before the server starts and rewrites every hardcoded height constant to your configured value using ASM bytecode transformation.

Patched systems (43 classes)

Category	Classes	What's fixed
Chunk storage	ChunkUtil, ChunkStore, ChunkColumn, BlockChunk, WorldChunk	Section arrays resized, constant fields updated, safe deserialization
Collision & physics	CollisionConfig, BlockDataProvider, WorldUtil, MotionControllerWalk, PositionProbeBase	Mobs collide with blocks above Y=320, ground detection bitmask fix
Network	SetupPacketHandler, GamePacketHandler, BlockChunkLoadPacketSystem, FluidLoadPacketGenerator	Client receives correct world height, packet section clamping
Interactions	BlockPlaceUtils, PlaceBlockInteraction, SimpleBlockInteraction, RunOnBlockTypesInteraction, TargetUtil, BlockSelection, IChunkAccessorSync	Block placement and targeting work above Y=320
NPC / AI	BodyMotionFindWithTarget, BlockTypeView	NPCs see and navigate blocks above Y=320
Spawning	SpawningContext, ChunkSpawningSystems, LocalSpawnControllerSystem, FloodFillPositionSelector	Entities spawn correctly at any height
Block systems	WorldNotificationHandler, ConnectedBlocksUtil, FixFillerBlocksSystem, EnvironmentChunkColumnWriter	Block notifications, connected blocks, environment writing
Gameplay	FireFluidTicker, FarmingSystems, FarmingSystems$Ticking, WaterGrowthModifierAsset, WeatherTracker, PortalSpawnFinder	Fire, farming, weather, portals work at full height
World generation	GeneratedBlockChunk, ChunkGenerator, ChunkGeneratorExecution, StagedChunkGenerator, GridUtils, FlatWorldGenProvider	Terrain generates up to the new height limit

Installation

1. Build the plugin (see below) or download the release jar.
2. Copy WorldHeightY320Plus-1.0.0.jar into your server's earlyplugins/ folder:

   <HytaleData>/UserData/Saves/<YourWorld>/earlyplugins/
   

3. Start the server. You'll see in the console:

   [Y320+] World height: 32736 blocks (1023 sections)
   [Y320+] Patched com.hypixel.hytale.math.util.ChunkUtil (1/43)
   ...
   

Configuration

By default the plugin sets world height to 32,736 blocks (1,023 sections) — the engine maximum. If you want a lower height, set it via any of the following (first found wins):

Method	Example
JVM property	-Dhytale.worldHeight=1024
JVM property (alt)	-Dhytale.world.height=1024
Environment variable	HYTALE_WORLD_HEIGHT=1024

Constraints

• Must be greater than 320 (the engine default).
• Must be a multiple of 32 (auto-rounded up if not).
• Maximum: 32,736 — hard engine limit (BlockChunk stores heights as short via ShortBytePalette; max signed short = 32,767 → ⌊32767/32⌋ × 32 = 32,736).

Building from source

Requires Java 25 (JDK 25 LTS).

cd WorldHeightY320Plus
./gradlew build

The built jar is at build/libs/WorldHeightY320Plus-1.0.0.jar.

Technical details

• Plugin type: Hytale Early Plugin (ClassTransformer, priority 10000)
• Bytecode library: ASM 9.8 (bundled as fat jar)
• Target runtime: Java 25
• Transformation approach: ClassReader → HeightPatchClassVisitor → ClassWriter
• Special patches:
  • Array normalization for chunk sections (handles old-format 10-section data)
  • Safe deserialization with error-recovery round-trip
  • Packet section clamping for client compatibility
  • Height probe redirection (getHeight → updateHeight)
  • Collision result bitmask fix for extended ground detection

Why 32,736 and not higher?

The Hytale engine stores per-block height values using ShortBytePalette, where getHeight(), setHeight(), and updateHeight() all operate on Java short (signed 16-bit: max 32,767). Any height value above 32,767 would overflow to negative, corrupting the heightmap. The largest multiple of 32 (section size) that fits is 32,736 (1,023 sections).

Increasing beyond this would require patching ShortBytePalette method signatures from short to int throughout the engine — a much more invasive transformation that risks breaking serialization formats.

Compatibility

• Hytale Server — tested with the current release.
• Other mods — the plugin runs at priority 10000 (early) and only transforms known target classes, so it should be compatible with other mods.
• Existing worlds — worlds created with Y=320 will work. Chunks saved with 10 sections are automatically expanded at load time.

License

MIT