Create an instant mirror copy of the current world to safely test, explore, and build without affecting your original save.
Description
InstantWorldMirror - Instant World Mirror
English | 中文
Instant Sandbox - Explore Without Consequences
InstantWorldMirror provides Minecraft players with an instant sandbox testing ground. Using the Dimension Mirror, you can create a mirror copy of the surrounding area at any location, freely explore, test, and experiment without worrying about any impact on the original world.
Core Use Cases
- Mod Testing: Test new mod functionality and compatibility in the mirror world without risking your main save
- Redstone Debugging: Copy your redstone contraptions for repeated testing and debugging without teardown costs
- Adventure Scouting: Explore dangerous areas in the mirror first to plan safe routes before venturing in
- Building Design: Preview building plans in the mirror, then build in the main world once satisfied
- Server Events: Provide safe activity spaces for players, with automatic cleanup after events
Features
Dimension Mirror
The Dimension Mirror is your key to the mirror world:
- Right-click any solid block to create an entry portal
- Supports Efficiency enchantment to reduce cooldown (20% reduction per level)
- No cooldown in Creative mode
- Supports creating mirrors from Overworld, Nether, End, and mod-added custom dimensions
Mirror World Mechanics
- Copies terrain within a configurable radius centered on the portal (default 10 chunks, configurable 1-32 chunks)
- Complete copying of blocks, block entities, biome data, and structure information
- Optional entity copying (mobs, decorations, etc.)
- Automatic synchronization of source world weather and time
- Natural mob spawning disabled by default, can be enabled via commands or config
Multiplayer Support
- Supports up to 8 parallel mirror dimensions, allowing multiple players to use their own mirror worlds simultaneously
- Multiple players can enter the same mirror session through the same portal
- Comprehensive permission system for server admins to control player access and item transfer rules
- Mirror world automatically enters cleanup when all players leave
Portal System
- Entry portal opens after world copy completes, lasts 5 minutes by default (configurable)
- Return portal in mirror world is permanent by default
- Use Dimension Mirror in mirror world to create return portal
- Automatic return to source world upon death
Performance Optimization
- Heightmap scanning technology skips air columns, significantly reducing unnecessary copying
- Section-level operations instead of block-by-block processing
- Sequential queue processing to avoid server overload
- Smart cleanup mechanism only processes modified chunks
Installation
- Install NeoForge 1.21+
- Download this mod JAR file
- Place in
.minecraft/modsfolder - Launch the game
Crafting Recipe
[Glass] [Obsidian] [Glass]
[Obsidian] [Ender Pearl] [Obsidian]
[Glass] [Obsidian] [Glass]Commands
All commands start with /iwm:
| Command | Description | Permission |
|---|---|---|
/iwm return |
Force return to source world | All players |
/iwm mob on/off/status |
Control mirror world mob spawning | OP (Level 2) |
/iwm allow <player> |
Allow player to use mirror feature | OP (Level 2) |
/iwm deny <player> |
Deny player from using mirror feature | OP (Level 2) |
/iwm itemtransfer <player> <true/false> |
Control player item transfer permission | OP (Level 2) |
/iwm status |
View dimension pool status and player info | OP (Level 2) |
/iwm forceclear <dimension> |
Force clear specified mirror dimension | OP (Level 3) |
/iwm purge |
Completely delete all mirror world saves (requires restart) | OP (Level 3) |
Configuration
Config file located at config/instantworldmirror-common.toml
Dimension Pool Settings
| Config | Default | Description |
|---|---|---|
| dimensionPoolSize | 4 | Mirror dimension pool size (1-8), determines max concurrent mirror sessions |
World Copy Settings
| Config | Default | Description |
|---|---|---|
| copyChunkRadius | 10 | Copy radius (chunks), total chunks = (radius*2+1)^2 |
| copyChunksPerTick | 2 | Chunks copied per tick, higher = faster but may cause lag |
| cleanupChunksPerTick | 4 | Chunks cleaned per tick |
| edgeCleanupRadius | 3 | Extra radius for BFS edge cleanup scan |
Portal Settings
| Config | Default | Description |
|---|---|---|
| entryPortalLifetime | 300 | Entry portal duration (seconds), -1 for permanent |
| returnPortalLifetime | -1 | Return portal duration (seconds), -1 for permanent |
| maxPortalLoadingTime | 600 | Maximum portal loading wait time (seconds) |
Item and Mob Settings
| Config | Default | Description |
|---|---|---|
| allowItemTransfer | false | Whether to allow players to bring items back by default |
| mirrorCooldown | 300 | Dimension Mirror cooldown (seconds), reduced by Efficiency |
| copyEntities | false | Whether to copy mob entities |
| copyDecorationEntities | true | Whether to copy decoration entities (paintings, item frames, etc.) |
| enableMobSpawning | false | Whether to allow natural mob spawning in mirror world |
Environment Settings
| Config | Default | Description |
|---|---|---|
| copyBiomes | true | Whether to copy biome data |
| copyStructures | true | Whether to copy structure data |
| copyHeightmaps | true | Whether to copy heightmap data |
Server Limits
| Config | Default | Description |
|---|---|---|
| maxMirrorWorldsPerPlayer | 1 | Maximum concurrent mirror sessions per player |
| staleSessionCleanupInterval | 300 | Stale session cleanup check interval (seconds) |
Client Settings
Client config located at config/instantworldmirror-client.toml
| Config | Default | Description |
|---|---|---|
| showCooldownHud | false | Show cooldown timer HUD in top-left corner |
Gameplay
- Craft a Dimension Mirror
- Go to the area you want to copy
- Right-click a solid block to create an entry portal
- Wait for world copy to complete (portal animation indicates loading state)
- Enter the portal to start exploring and experimenting in the mirror world
- Use Dimension Mirror to create a return portal, or use
/iwm returncommand - Mirror world automatically cleans up after you leave, ready for next use
Important Notes
- By default, items obtained in the mirror world are NOT kept when returning
- Cannot build Nether or End portals in the mirror world
- Each new mirror session copies the world fresh
- Changes in mirror world do NOT affect the source world
- Server admins have full control over player access permissions
Downloads
- CurseForge - Mod download
- GitHub - Source code
License
Apache License 2.0