Entity Attributes & Spawns

Two small registries configure custom living entities: their default attributes, and where they naturally spawn.

Entity attributes

dev.architectury.registry.level.entity.EntityAttributeRegistry

Every LivingEntity needs a set of default attributes (max health, movement speed, and so on). Register them with EntityAttributeRegistry.register, passing your entity type and an AttributeSupplier.Builder:

EntityAttributeRegistry.register(
    MyMod.MY_MOB,                  // Supplier<? extends EntityType<? extends LivingEntity>>
    () -> Mob.createMobAttributes()
        .add(Attributes.MAX_HEALTH, 20.0)
        .add(Attributes.MOVEMENT_SPEED, 0.25)
);

Call this from your common initializer (after your entity type is registered).

Spawn placements

dev.architectury.registry.level.entity.SpawnPlacementsRegistry

Control where and how a Mob spawns naturally with SpawnPlacementsRegistry.register:

SpawnPlacementsRegistry.register(
    MyMod.MY_MOB,                            // Supplier<? extends EntityType<T>>
    SpawnPlacementTypes.ON_GROUND,           // SpawnPlacementType
    Heightmap.Types.MOTION_BLOCKING_NO_LEAVES,
    (type, level, spawnReason, pos, random) ->
        Monster.checkMonsterSpawnRules(type, level, spawnReason, pos, random) // SpawnPredicate<T>
);

The predicate decides whether a spawn attempt at a given position is allowed.