Archive Entry

Item entity order and age mechanics

RDtomes-and-diagramsRD003Updated Jan 03, 2026Archived Jan 02, 2026

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Authors:Andrews54757

Endorsed by:Andrews54757

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Item entities have different properties which the technical minecraft community confusingly all call "age" for some reason. but make no mistake, it's not that simple.

ItemEntity.age: Despawn counter

Starts at 0 when the item is spawned, then increments by 1 every gtDefinition: Minecraft iteratively runs its processing code in a loop. One cycle of this loop is called a Tick or Gametick (gt). Gameticks are also used as the default measurement of time while working with re... inside entity tick. if passes 6000 (5 minutes), then the item is deleted. When merging, the merged entity's age is set to the minimum of the two merging entities. in effect, the lifetime of the item entityDefinition: Item entities are items in entity form. Each item entity can have a full stack of items, up to 64 items for 64-stackables. ## Item entity tick Every game tick, item entities will do the following ... is set to the longest of the two merging entities.

ItemEntity.tickCount: Tick counter

Starts at 0 when the item is spawned, then increments by 1 every gt. Every entity has this. increment happens before entity tick call in ServerLevel.tickNonPassenger.

ItemEntity.id: ID counter

Is fixed for an entity. Each entity is given an id that is one plus the previous id given to the previous entity.

Ticking Order

This is the order inside the ServerLevel.entityTickList which defines which entity is ticked first. Order is set by order of spawning.

Iteration Order

This is the order inside the EntitySectionStorage which is based per subchunk. If you want to find entities in a certain area (eg for picking up item entities with a player or hopper), you will get a list with the order defined here. Crossing subchunks will change the order.

Modulo 4

When ticked, entity uses the sum ItemEntity.tickCount + ItemEntity.id and checks if it is divisible by 4 to begin self-movement. Essentially makes it so items spawned at same tick drop at different ticks from rest, one of 4. Combined with the fact that the entity id is incremented with a globalDefinition: Annotates if a signal comes from a global system ( a 'brain' ), or from within a Slice. For example, one global clock could send signals to 8 slices on an interval, or all 8 slices could have their... counter, you can use this mechanic to do wireless redstone.

Item entity merging

When ticked (so obeys ticking order), entity checks if ItemEntity.tickCount is divisible by 2 if the item has crossed a block pos boundary, or 40 otherwise. Then it will check if it can merge with other entities in the same area (obeys iteration order). merging will reuse the entity with larger count, and discard the smaller count entity.