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AutoSieve Drop Registration

The AutoSieve supports dynamic drop registration using ScriptEvents.
Drops are sent as a JSON string after worldLoad, and UtilityCraft parses and registers them automatically.

Sending the ScriptEvent​

import { system, world } from "@minecraft/server";

const newDrops = {
  "minecraft:gravel": [
    { item: "minecraft:string", amount: 1, chance: 0.05 },
    { item: "minecraft:bone_meal", amount: 1, chance: 0.15 }
  ]
};

world.afterEvents.worldLoad.subscribe(() => {
  system.sendScriptEvent(
    "utilitycraft:register_sieve_drop",
    JSON.stringify(newDrops)
  );
});

You must always:

  • Wait for worldLoad
  • Use JSON.stringify
  • Send through utilitycraft:register_sieve_drop

Drop Object Fields​

Each block entry maps to an array of drops. Each drop may contain the following properties:

  • item
    Item identifier that can drop (namespace:item_name).

  • amount
    How many items are granted on success.

  • chance
    Drop probability from 0 to 1.
    Example: 0.25 means 25% chance.

  • tier (optional)
    Minimum mesh tier required for the drop to be eligible.
    If not defined, defaults to 0.

Example Drop Object​

const drops = {
  "minecraft:sand": [
    { item: "utilitycraft:copper_chunk", amount: 1, chance: 0.25, tier: 1 },
    { item: "minecraft:gunpowder", amount: 1, chance: 0.12 }
  ],
  "utilitycraft:crushed_netherrack": [
    { item: "utilitycraft:nether_quartz_chunk", amount: 1, chance: 0.33, tier: 1 }
  ]
};

Accepted Blocks and Basic Sieve Rules​

UtilityCraft defines an acceptedBlocks list for the Basic Sieve (tier 0).

Important behavior:

  • The Basic Sieve ignores any input block not present in acceptedBlocks, even if the block has drops registered.
  • Higher tiers may accept additional blocks depending on UtilityCraft configuration.

If targeting tier 0 usage, ensure the input block is supported.

Notes​

  • Drops are registered at runtime and do not require modifying UtilityCraft source files.
  • If a block entry does not exist, it will be created automatically.
  • Invalid drop definitions are ignored safely.