World Settings - Chunker

Overview

World settings allow you to customize world-level properties during conversion. This includes game rules, difficulty, spawn points, and other world metadata that gets embedded in the level.dat or equivalent file.

Configuration File

World settings are defined in world_settings.chunker.json or passed via the -s flag (CLI.java:163-182).

File Structure

World settings are stored as a JSON object containing key-value pairs (CLI.java:177):

world_settings.chunker.json

{
  "LevelName": "My Converted World",
  "Difficulty": 2,
  "hardcore": false,
  "GameType": 0
}

World settings are applied directly to the world data structure. The available fields depend on the output edition and version.

Common Settings

While the exact fields available depend on the target edition, here are commonly used settings:

World Name

{
  "LevelName": "My Custom World Name"
}

Sets the world’s display name.

Difficulty

{
  "Difficulty": 2
}

Values:

0: Peaceful
1: Easy
2: Normal
3: Hard

Game Mode

{
  "GameType": 1
}

Values:

0: Survival
1: Creative
2: Adventure
3: Spectator

Hardcore Mode (Java)

{
  "hardcore": true
}

Enables hardcore mode (Java Edition only).

Spawn Position

{
  "SpawnX": 0,
  "SpawnY": 64,
  "SpawnZ": 0
}

Sets the world spawn point coordinates.

Time

{
  "Time": 0,
  "DayTime": 0
}

Sets the world time:

0: Dawn
6000: Noon
12000: Dusk
18000: Midnight

Game Rules

Game rules can also be configured:

{
  "GameRules": {
    "doDaylightCycle": "true",
    "doMobSpawning": "true",
    "keepInventory": "true",
    "mobGriefing": "false"
  }
}

Game rule values must be strings ("true" or "false"), not booleans.

Complete Examples

Peaceful Creative World

world_settings.chunker.json

{
  "LevelName": "Creative Build World",
  "Difficulty": 0,
  "GameType": 1,
  "GameRules": {
    "doDaylightCycle": "false",
    "doWeatherCycle": "false",
    "doMobSpawning": "false"
  },
  "Time": 6000,
  "DayTime": 6000
}

Hardcore Survival

world_settings.chunker.json

{
  "LevelName": "Hardcore Challenge",
  "Difficulty": 3,
  "GameType": 0,
  "hardcore": true,
  "GameRules": {
    "naturalRegeneration": "true",
    "keepInventory": "false"
  }
}

Adventure Map

world_settings.chunker.json

{
  "LevelName": "Adventure Map",
  "GameType": 2,
  "Difficulty": 2,
  "GameRules": {
    "commandBlockOutput": "false",
    "mobGriefing": "false",
    "doTileDrops": "false",
    "naturalRegeneration": "false"
  },
  "SpawnX": 100,
  "SpawnY": 64,
  "SpawnZ": 200
}

Skyblock Setup

world_settings.chunker.json

{
  "LevelName": "Skyblock",
  "GameType": 0,
  "Difficulty": 2,
  "SpawnX": 0,
  "SpawnY": 100,
  "SpawnZ": 0,
  "GameRules": {
    "keepInventory": "true",
    "mobGriefing": "false"
  }
}

Usage

# Place in world directory
my_world/world_settings.chunker.json

# Run conversion
java -jar chunker-cli.jar -i my_world -f BEDROCK_1_20_80 -o output

Java vs Bedrock Differences

Java Edition Specific

{
  "hardcore": true,
  "allowCommands": true,
  "DataVersion": 3465
}

Bedrock Edition Specific

{
  "Generator": 1,
  "NetherScale": 8,
  "bonusChestEnabled": false,
  "bonusChestSpawned": false
}

Universal Settings

{
  "LevelName": "World",
  "Difficulty": 2,
  "GameType": 0,
  "SpawnX": 0,
  "SpawnY": 64,
  "SpawnZ": 0,
  "Time": 0
}

Field Format

World settings use the underlying NBT format field names:

Field names are case-sensitive
Integer values: Use numbers (2, not "2")
Boolean values: Use booleans (true, not "true")
Game rules: Use strings ("true", not true)

Incorrect field names or types may be silently ignored or cause conversion errors.

Common Game Rules

Rule	Description	Default
`keepInventory`	Keep items on death	`false`
`doDaylightCycle`	Sun and moon move	`true`
`doWeatherCycle`	Weather changes	`true`
`doMobSpawning`	Mobs spawn naturally	`true`
`mobGriefing`	Mobs can destroy blocks	`true`
`naturalRegeneration`	Health regenerates	`true`
`commandBlockOutput`	Show command block output	`true`
`doFireTick`	Fire spreads	`true`
`showDeathMessages`	Show death messages	`true`
`announceAdvancements`	Announce advancements	`true`

Game rule availability varies by edition and version. Some rules only exist in Java or Bedrock.

Validation

Chunker applies world settings during conversion (CLI.java:175-181):

Valid settings are applied to the output world
Invalid or unknown fields are typically ignored
Type mismatches may cause errors

Always test your world settings on a copy before using them on important worlds.

Discovering Available Settings

To find available settings for your target version:

Create a world in the target edition/version
Use NBT editors like NBTExplorer or Amulet
Examine the level.dat file structure
Use those field names in your world_settings.chunker.json

Exporting Settings

Generate world settings from the web UI:

Visit chunker.app
Go to Advanced Settings → Converter Settings
Configure world properties
Export the world_settings.chunker.json file

Partial Updates

You only need to specify settings you want to change:

{
  "Difficulty": 0
}

This changes only the difficulty and leaves all other settings unchanged.

Overriding Original Settings

World settings override values from the input world:

Input world has Difficulty: 2
Settings file has Difficulty: 0
Output world will have Difficulty: 0

Best Practices

Test on copies before applying to production worlds
Use minimal settings - only change what you need
Document your settings for future reference
Check edition compatibility - some settings are edition-specific
Validate field names using NBT editors

Common Use Cases

Reset Difficulty

Change world difficulty after conversion

Fix Spawn Point

Set correct spawn coordinates

Rename World

Give converted world a new name

Configure Rules

Set game rules for maps or servers

Troubleshooting

Settings not applying

Check JSON syntax is valid
Verify field names are spelled correctly (case-sensitive)
Ensure value types match expected format
Check that the setting is supported by target edition

Conversion fails with settings error

Validate JSON structure
Remove invalid or unknown fields
Check for type mismatches (number vs string)
Test with minimal settings first

Game rules not working

Ensure game rule values are strings: "true" not true
Check game rule name spelling
Verify the rule exists in target edition/version

World name unchanged

Ensure using LevelName not levelName (case matters)
Check file is being loaded (use -s flag to verify)
Try setting in web UI and exporting configuration

Advanced Settings

World Generation

{
  "generatorName": "default",
  "generatorVersion": 1,
  "generatorOptions": ""
}

World Border

{
  "BorderCenterX": 0.0,
  "BorderCenterZ": 0.0,
  "BorderSize": 60000000.0
}

Version Info

{
  "Version": {
    "Name": "1.20.4"
  }
}

Advanced settings should be used with caution. Incorrect values can cause world corruption or loading issues.

Configuration Overview

Learn about all configuration options

Converter Settings

Control conversion behavior

Dimension Mapping

Map dimensions between editions

Get Started

Using Chunker

Advanced

Development

​Overview

​Configuration File

​File Structure

​Common Settings

​World Name

​Difficulty

​Game Mode

​Hardcore Mode (Java)

​Spawn Position

​Time

​Game Rules

​Complete Examples

​Peaceful Creative World

​Hardcore Survival

​Adventure Map

​Skyblock Setup

​Usage

​Java vs Bedrock Differences

​Java Edition Specific

​Bedrock Edition Specific

​Universal Settings

​Field Format

​Common Game Rules

​Validation

​Discovering Available Settings

​Exporting Settings

​Partial Updates

​Overriding Original Settings

​Best Practices

​Common Use Cases

Reset Difficulty

Fix Spawn Point

Rename World

Configure Rules

​Troubleshooting

​Advanced Settings

​World Generation

​World Border

​Version Info

​Related

Configuration Overview

Converter Settings

Dimension Mapping

Build docs developers (and LLMs) love

Overview

Configuration File

File Structure

Common Settings

World Name

Difficulty

Game Mode

Hardcore Mode (Java)

Spawn Position

Time

Game Rules

Complete Examples

Peaceful Creative World

Hardcore Survival

Adventure Map

Skyblock Setup

Usage

Java vs Bedrock Differences

Java Edition Specific

Bedrock Edition Specific

Universal Settings

Field Format

Common Game Rules

Validation

Discovering Available Settings

Exporting Settings

Partial Updates

Overriding Original Settings

Best Practices

Common Use Cases

Troubleshooting

Advanced Settings

World Generation

World Border

Version Info

Related