MECHA - Multiple Entity Collision Hitboxes API
If you have ever tried to give a custom Minecraft entity a hitbox that actually matches its shape, you already know the pain. Vanilla mobs get one box and that is it. Wings, tails, long necks, stacked body segments, and oversized bosses all end up wrapped in a single crude cuboid that never feels right. The MECHA - Multiple Entity Collision Hitboxes API solves exactly that problem by letting mod developers attach more than one collision box to a single entity.
This lightweight library is a developer-facing tool, but it quietly powers the kind of modded creatures players remember. Whether you are building a dragon with a sweeping tail or a multi-part machine boss, MECHA gives you the framework to do it cleanly.
What MECHA Actually Does
At its core, MECHA is a simple API for enabling custom entities to implement more than one collision box. Instead of fighting Minecraft's built-in entity system, you implement the MultiCollidable interface in your custom entity class and override the getColliders method. That method returns a list of VoxelShape objects, and each one becomes an active collider on the entity.
The result is precise, shape-aware collision. A creature with two stacked slab-sized boxes, for example, can be hit on the lower half or the upper half independently, which opens the door to directional damage, weak points, and segmented bosses.
Key features at a glance
- Attach multiple collision boxes to a single custom entity.
- Simple interface implementation with a single overridden method.
- Works with standard VoxelShape cuboids, so positioning is fully under your control.
- Ideal for multi-part bosses, segmented creatures, and vehicles.
- Lightweight and dependency-friendly for modpacks and libraries.
Supported Versions and Loader
MECHA is built for the Fabric loader and targets modern Minecraft releases, with the API distributed through Modrinth. Because it is a library, it does not add content on its own; it exists so other mods can depend on it. That means version compatibility matters, and you should always match the MECHA build to the Minecraft version your other mods are running.
If you are hunting for a reliable build, you can download MECHA - Multiple Entity Collision Hitboxes API from Modrinth and drop it straight into your mods folder alongside any mods that list it as a dependency. Keeping the library version aligned with your game version prevents the classic "missing dependency" crash on startup.
How to Install MECHA
Installing a library mod is refreshingly simple, and MECHA is no exception. Here is the short version for players:
- Make sure Fabric Loader is installed for your Minecraft version.
- Place the Fabric API jar in your mods folder.
- Add the MECHA jar to the same mods folder.
- Add any mods that depend on MECHA.
- Launch the game and confirm everything loads without errors.
For developers, the setup is just as clean. You add the Modrinth Maven repository and the correct MECHA version to your build.gradle file, then declare the dependency with the modImplementation line. From there, implementing MultiCollidable in your entity class is all it takes to start defining custom colliders.
A quick example
Imagine an entity that needs two colliders, each the size of a slab. You build a list of VoxelShape cuboids, grab the entity's block position, and add one box for the bottom half and another for the top half. Return that list from getColliders, and MECHA handles the rest. It is a small amount of code for a big jump in how your entities feel in combat.
If you prefer a friction-free setup, the foxygame.net launcher is worth a look. It offers one-click install for MECHA - Multiple Entity Collision Hitboxes API and keeps your add-ons updated automatically, so version mismatches stop being your problem. The launcher's add-on catalog also makes it easy to pair MECHA with the mods that rely on it, all without manually editing config files.
Why Developers and Players Both Benefit
For mod authors, MECHA removes a huge amount of guesswork. You no longer need hacky workarounds or custom ray-tracing logic just to make a creature's tail register hits. The interface is small, predictable, and easy to read, which means less time debugging and more time building the content players actually want.
For players, the payoff shows up in gameplay. Multi-part bosses feel more dynamic when you can strike specific sections. Creatures with wings, limbs, and tails behave more naturally because their collision matches their silhouette. Even something as simple as a two-box entity changes how combat reads on screen.
Final Thoughts
The MECHA - Multiple Entity Collision Hitboxes API is one of those quiet libraries that makes ambitious mods possible. It is not flashy on its own, but it unlocks precise, shape-aware collision for custom entities in a way vanilla Minecraft simply cannot. If you are developing creatures with complex bodies, or you just want to run mods that depend on it, MECHA - Multiple Entity Collision Hitboxes API for Minecraft is a small download with a surprisingly large impact. Grab it, match your versions, and let your entities finally collide the way they were meant to.