Java Tutorial: Register a Machine, Recipe Type, and Recipe

MBD2 21.1.1

This tutorial ships an editor-authored single-block crusher and recipe-type UI inside a Java mod, then adds an iron_ingot -> iron_nugget built-in recipe in Java.

The Java registration path ships the exported Recipe Type project, including this viewer template.

Result and IDs

Keep these IDs stable throughout the tutorial:

Object	ID
Machine definition/block	examplemod:crusher
Recipe type	examplemod:crushing
Recipe	examplemod:crush_iron

The machine ID and recipe-type ID are deliberately different. The machine's Recipe Logic setting must reference examplemod:crushing.

1. Configure Gradle

Follow Gradle dependency setup, then confirm:

./gradlew.bat compileJava

Your code needs MBD2 and LDLib2 on compileClasspath; the development run also needs both mods at runtime.

2. Author and export the products

Open /mbd2_editor and create a recipe-type project:

1. Set its registry ID to examplemod:crushing.
2. Add item input and item output widgets to the recipe UI.
3. Export the productive recipe-type file as crushing.rt.

Create a single-machine project:

1. Set its registry ID to examplemod:crusher.
2. Add one item Trait with recipeHandlerIO = IN; name it input.
3. Add one item Trait with recipeHandlerIO = OUT; name it output.
4. Enable Recipe Logic and choose examplemod:crushing.
5. Generate/author a UI containing both Traits and a progress bar.
6. Export the productive machine file as crusher.sm.

Package the products at these exact classpath paths:

src/main/resources/
└─ assets/
   └─ examplemod/
      └─ mbd/
         ├─ recipe_types/
         │  └─ crushing.rt
         └─ machines/
            └─ crusher.sm

Do not hand-edit these NBT product files. Keep editable projects separately and treat .rt/.sm as exported build artifacts.

3. Subscribe on the mod event bus

package com.example.examplemod;

import com.lowdragmc.mbd2.common.event.MBDRegistryEvent;
import net.neoforged.bus.api.IEventBus;
import net.neoforged.fml.common.Mod;

@Mod(ExampleMod.MOD_ID)
public final class ExampleMod {
    public static final String MOD_ID = "examplemod";

    public ExampleMod(IEventBus modBus) {
        modBus.addListener(MBDRegistration::registerRecipeTypes);
        modBus.addListener(MBDRegistration::registerMachines);
    }
}

MBDRegistryEvent implements IModBusEvent; do not attach these listeners to NeoForge.EVENT_BUS.

4. Register the recipe type and Java recipe

package com.example.examplemod;

import com.lowdragmc.mbd2.api.recipe.MBDRecipeType;
import com.lowdragmc.mbd2.api.registry.MBDRegistries;
import com.lowdragmc.mbd2.common.event.MBDRegistryEvent;
import net.minecraft.resources.ResourceLocation;
import net.minecraft.world.item.Items;

public final class MBDRegistration {
    public static final ResourceLocation CRUSHING = id("crushing");
    public static final ResourceLocation CRUSH_IRON = id("crush_iron");

    private MBDRegistration() {}

    public static void registerRecipeTypes(MBDRegistryEvent.MBDRecipeType event) {
        event.registerFromResource(
            ExampleMod.class,
            "examplemod/mbd/recipe_types/crushing.rt"
        );

        MBDRecipeType crushing = MBDRegistries.RECIPE_TYPES.get(CRUSHING);
        if (crushing == null) {
            throw new IllegalStateException("Missing recipe type " + CRUSHING);
        }

        crushing.recipeBuilder(CRUSH_IRON)
            .inputItems(Items.IRON_INGOT)
            .outputItems(Items.IRON_NUGGET, 9)
            .duration(100)
            .priority(0)
            .saveAsBuiltinRecipe();
    }

    private static ResourceLocation id(String path) {
        return ResourceLocation.fromNamespaceAndPath(ExampleMod.MOD_ID, path);
    }

    // registerMachines is added in the next step.
}

registerFromResource prepends /assets/, so its argument is examplemod/..., not assets/examplemod/....

saveAsBuiltinRecipe() inserts the built recipe into this recipe type's built-in recipe map. buildRawRecipe() only returns an object and would not make the recipe available by itself.

5. Register the machine product

Add this method to MBDRegistration:

public static void registerMachines(MBDRegistryEvent.Machine event) {
    event.registerFromResource(
        ExampleMod.class,
        "single_machine",
        "examplemod/mbd/machines/crusher.sm"
    );
}

Java resource type keys are:

Product	Type key	Suffix
Single machine	single_machine	.sm
Multiblock controller	multiblock	.mb

These differ from KubeJS's single alias. create_machine/kinetic is not a current public registration path.

The machine definition registers its generated block, item, block entity type, renderer, and exposed capabilities later in MBD2's registration lifecycle. Do not duplicate them in your own DeferredRegister.

6. Start and verify

Run the client and check the log in this order:

Loading recipe types
Loading machines

Then verify:

1. /give @s examplemod:crusher resolves.
2. The placed block uses the authored base state/model.
3. Its UI shows input, output, and the progress widget.
4. One iron ingot in the input starts examplemod:crush_iron.
5. After 100 working ticks, nine nuggets enter the output.
6. JEI/REI/EMI shows the recipe if a supported viewer is installed.

If the block exists but does not process, first confirm the machine product references examplemod:crushing and both item Traits expose the correct recipe IO.

Programmatic alternatives

• Create new MBDRecipeType(id) and event.register(type) when no editor-authored recipe UI/proxy configuration is needed.
• Build an MBDMachineDefinition and call event.register(definition) when the entire definition must be generated in code.
• Use MBDRecipeBuilder#save(RecipeOutput) only from a configured data-generation path; use saveAsBuiltinRecipe() for recipes shipped directly by registration code.

Continue with custom machine/reference APIs for builder details and RecipeLogic lifecycle for runtime behavior.