What Is Sus MultiBlocked and Why It Changes Everything
Building complex multiblock structures in Minecraft mods has always been a challenge. Hardcoding every block position, orientation, and metadata into Java classes is tedious and error-prone. Sus MultiBlocked flips that workflow on its head. This library lets you design your multiblock directly in the game world, assign custom variables to each block, and export a clean JSON file that your code can read. No more guessing offsets or rewriting logic every time you tweak a structure.
How the In-Game Design Process Works
The core of Sus MultiBlocked is a special item called the Zone Selector. It operates in two modes, toggled by a configurable keybind. In Zone Selector mode, you define the bounding box of your structure and set global variables—key-value pairs that apply to the entire multiblock. You can name them, choose their type (integer, string, etc.), and assign default values. These variables are saved even after you close the GUI, so you can iterate quickly.
Switching to Block Customiser mode lets you fine-tune each block. Right-click any block in your structure to open a GUI where you override the global variables for that specific position. For example, you might set a "temperature" integer to 500 for a lava block and 0 for an obsidian block. Shift-right-clicking designates a master block, which serves as the reference point for all offset calculations. A second special keybind writes the entire structure to a JSON file, capturing every block’s relative coordinates, type, metadata, and your custom variables.
Turning JSON into Code: The Three Essential Classes
Once you have the JSON file, you create three classes in your mod. The first extends MultiStructure—this is the main controller where you specify the JSON path, whether the structure can rotate, and validation rules. The second is a MultiStructureElement subclass that represents each block. It automatically receives the x, y, z offsets and stored block data from the JSON, plus any custom variables you defined. The third is an optional AdditionalData class for fields not coming from JSON, like texture references or block instances.
This separation keeps your code clean. You can, for instance, use a "replacement block meta" variable to dynamically set the metadata during construction, avoiding hardcoded offsets entirely. The library handles orientation: you build your structure facing "up" by default, then specify which facings are valid (north, east, etc.) and whether the structure can spin around that facing. For large structures, you can optimize validation to trigger only when the master block is clicked, saving server ticks.
Practical Example: From Infernal Furnace to Custom Altar
Imagine you want an infernal furnace made of obsidian, lava, and netherrack. You build it in a creative world, use the Zone Selector to set a "heatLevel" integer variable, then assign different heat values to each block via the Block Customiser. After exporting the JSON, you write a MultiStructure class that loads the file, a MultiStructureElement that includes the heatLevel field, and an AdditionalData class if needed. In your tile entity logic, you read the heatLevel from each element and adjust smelting speed accordingly. The entire process takes minutes instead of hours.
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Key Features That Make Multiblock Creation Painless
- In-game variable system: Define global and per-block variables with a simple GUI, no coding required.
- Automatic offset calculation: The master block sets the origin; all other positions are relative, eliminating coordinate math.
- JSON export: Structures are saved as portable JSON files, ready to be loaded by your mod.
- Rotation and facing support: Configure which facings are valid and whether the structure can spin, all from your MultiStructure class.
- Validation optimization: Choose between validating on any block click or only the master block for large structures.
- Kotlin compatibility: The library is written in Kotlin, but works with any JVM language; just include a Kotlin runtime like ASJCore.
Getting Started with Your First Multiblock
After installing the library and its Kotlin dependency, craft the Zone Selector item. Build your structure in a test world, then use the selector to set global variables—think of them as the shared properties of your multiblock. Next, customize individual blocks by right-clicking them and overriding values. Set a master block, choose an output file name, and export. The resulting JSON contains everything: block types, metadata, offsets, and your custom variables.
In your mod code, create a class extending MultiStructure. Override the source path to point to your JSON, set the data class to your element class, and define allowed facings. Your element class should have a constructor that accepts the JSON fields plus any extra data from your AdditionalData class. From there, you can access variables like "heatLevel" or "linkedInventorySlot" directly in your tile entity logic. The library even includes a disabled example structure—a tower—to study.
Why This Library Beats Hardcoding
Traditional multiblock systems force you to manually define every block position in code, often with nested loops and fragile coordinate checks. Changing the structure means rewriting and recompiling. Sus MultiBlocked decouples design from implementation. You can tweak the layout in-game, re-export the JSON, and your code adapts instantly. This is especially powerful for modpacks or servers where balance adjustments are frequent. The visual, interactive approach also reduces bugs: you see exactly what you are building, and the exported JSON mirrors that reality.
Conclusion: A Must-Have for Mod Developers
Sus MultiBlocked transforms multiblock creation from a tedious coding chore into an intuitive in-game design process. By separating structure definition from code logic, it saves time, reduces errors, and opens up creative possibilities that were previously impractical. Whether you are crafting a simple altar or a sprawling reactor, this library gives you the tools to iterate quickly and maintain clean, readable code. For any modder tired of hardcoding block positions, Sus MultiBlocked is the upgrade your workflow deserves.