Always use the latest (stable) version of SeedMapper! If you want to play on an older version of Minecraft, use ViaFabricPlus. This mod allows you to use the latest features of SeedMapper, while still being able to play on older Minecraft versions.

SeedMapper

In-game Minecraft Fabric mod that allows you to do various things with the world seed. For reference, have a look at the features this mod has. Keep in mind though, this mod requires you to have access to the seed. If the seed is not known, you could crack it using SeedCrackerX by 19MisterX98. For questions and support please head to my Discord.

Installation

1. Install the Fabric Loader.
2. Download the Fabric API and move it to your mods folder:
   • Linux/Windows: .minecraft/mods.
   • Mac: minecraft/mods.
3. Download SeedMapper from the releases page and move it to your mods folder.

IMPORTANT

You need to have at least Java 23 installed to use this mod. I recommend to get Java 23 (or higher) from adoptium.net. Next, configure your Minecraft launcher to use this release of Java.

• Vanilla launcher: Go to Installations -> Edit -> More options -> Java executable.
• MultiMC: Go to Edit Instance -> Settings -> Java -> Java Installation.
• PrismLauncher: Go to Settings -> Java -> Java Runtime -> Auto-Detect....
• Modrinth App: Go to Instance settings -> Java and memory -> Custom Java installation -> Browse

Sometimes it may be necessary to click the option for skipping the Java compatibility check.

If you are on Windows, make sure to select javaw.exe, not java.exe.

If you run into issues, contact your launcher's support.

Features

Before using any of these commands, make sure the seed has been configured using /sm:config Seed set <seed>.

Seed map

Usage: /sm:seedmap

Opens an explorable seed map based on the configured seed. You can move the map by dragging the mouse, and zoom in or out by using the scroll wheel. You can toggle what features are visible by clicking the feature toggles at the top of the screen. This command is especially useful in combination with the /sm:source command!

Biome locating

Usage: /sm:locate biome <biome>.

Locates a given biome closest to the player. All biomes in all dimensions are supported.

Structure locating

Usage: /sm:locate feature <structure>[<pieces>]{<variants>}.

Locates a given structure closest to the player. All structures in all dimensions are supported. However, due to limitations in the underlying library, some structures (in particular desert pyramids, jungle temples and woodland mansions) may result in occasional false positives. For more advanced querying you can also use piece and variant data to further restrict the search. For example, the following command will search for end cities with ships: /sm:locate feature structure end_city[end_ship].

Ore vein locating

Usage: /sm:locate orevein (copper|iron).

Locates an ore vein closest to the player. The coordinates of the first ore vein block found will be returned. After this, you can use /sm:highlight orevein [chunks] to highlight the other ores.

Loot locating

Usage: /sm:locate loot <amount> <item> [<enchantment conditions>].

Locates chest loot closest to the player. All versions from 1.13 onwards are supported. SeedMapper will search through the chest loot of structures to find loot that matches the item and enchantment conditions. Note that queries for unobtainable loot and illegal enchantment combinations are not prevented by the command. If a search is taking too long, you should probably cancel it using /sm:stoptask.

Ore highlighting

Usage: /sm:highlight block <block> [chunks].

Highlights the specified block in the world. All versions from 1.13 onwards are supported. Due to high dependence on the OCEAN_FLOOR_WG heightmap, coal, copper and emerald ore locations may be off.

Ore vein highlighting

Usage: /sm:highlight orevein [chunks].

Highlights ore veins in the world. Raw ore blocks that generate as part of the ore vein are highlighted distinctly. Filler blocks are ignored.

Slime chunk locating

Usage: /sm:locate slimechunk.

Locates a slime chunk closest to the player. This will always be accurate.

Source mutation

Usage: /sm:source (run)|(as <entity>)|(positioned <position>)|(rotated <rotation>)|(in <dimension>)|(versioned <version>)|(seeded <seed>).

Executes a given command from a modified source. For example, modifying the source's position will execute the command as if you were in that position. This command is really powerful, use it!

Building from source

This mod internally uses (a fork of) the C library cubiomes by Cubitect. Java bindings for this library were created with (also a fork of) jextract. The bindings use the Foreign Function & Memory API from Project Panama. See CreateJavaBindingsTask.java for the Gradle task that automates this.

To build the mod locally, follow these steps:

1. Clone the repository:

   git clone --recurse-submodules https://github.com/xpple/SeedMapper
   cd SeedMapper
   

2. Compile cubiomes to a shared library. MSVC cannot be used to build the project! The following is for Windows:

   cd src/main/c/cubiomes
   cmake -S . -B build -DCMAKE_BUILD_TYPE=Release
   cmake --build build --config Release
   cp build/cubiomes.dll ../../resources/cubiomes.dll
   cd ../../../../
   

3. Install LLVM (version 13.0.0 is recommended) and set the environment variable LLVM_HOME to the directory where LLVM was installed.
4. Compile jextract. Again, the following is for Windows:

   cd jextract
   ./gradlew --stacktrace -Pjdk_home="$env:JAVA_HOME" -Pllvm_home="$env:LLVM_HOME" clean verify
   cd ../
   

5. Build the mod:

   ./gradlew build
   

   You should find the Java bindings in src/main/java/com/github/cubiomes.

Lastly, you can also consult the GitHub Actions workflow file, which contains complete build instructions for each major OS.