Persistent Entities

Every machine has an entity behind it, which is what its UI is really a container of. By default that entity is temporary: it is spawned when a player interacts with the block and can despawn after.

Set description.persistentEntity to true in your machine definition if your machine needs its entity to stay persistent. This changes two things:

• The entity is spawned when the block is placed, rather than when a player first interacts with it.
• Hitting the entity does not despawn it.

The main reason to want this is direct access to the entity's container. An item slot element stores its contents as a MachineItemStack, which cannot hold everything an item can carry, so a machine that has to accept arbitrary items needs a persistent entity and its real container instead. See Machine UI.

Cleaning Up

Hitting a persistent entity no longer destroys the machine, so if you want that behavior, or any other way to destroy the machine, you have to implement it yourself.

Call removeMachineData to clean up machine data and update networks. It will not remove the block or the entity. To remove the block, entity, and clean up data, use destroyMachine instead.