How to Make an Item Extension


Item extensions allow you to add additional item properties to a set item. Item extensions offer properties for composting, fuel for blast furnaces, furnaces and, smokers and dispense behaviour.

Prior to this element type being made there was a fuel element type but has since been merged into item extensions.

Before you start

You may want to create your own item to apply fuel, compost, or custom dispense behaviour to the item, though it is possible to change vanilla items, it may cause conflict with other mods if you do so.

Creation and naming

  • First, go to the workspace.
  • Next, click on Create new element.
  • Type the name of your item extension. Names must not be repeated! The end-user will not see this name, so name it something that you can identify. One way you can prevent your item extension name from being repeated is to put the mod type before your mod name, for example: ItemExtensionMapleLeaf or MapleLeafFuel.
  • Click next.

Item extension settings

Setting name Setting description
Item extension source: This is the item that you will apply the additional properties to.

Item as a fuel

Setting name Setting description
Make this item a fuel: When this box is checked the item can be used as fuel in furnaces, blast furnaces or smoker blocks.
Fuel burn time (power):

This is the amount of time in ticks that the item will burn when used. Most wood blocks like planks have a burn time of 300 ticks (15 seconds). 

There are 20 ticks in a second so if you want to calculate seconds multiply seconds by 20 (ticks) to get your burn time for your fuel.

You can also click the green plus icon to set a conditional burn time value. This can be handy when you want the value to be based on something dynamic in time or have more control over other procedures.

Fuel burning success chance: This allows you to set a condition procedure when the item should be used as fuel. Similar to the fuel value condition this will allow or deny the smelting block to use the item based on this condition.

Item as a compost material

Setting name Setting description
Chance of success to compost: This is the percent chance that the composter will upgrade to the next level. This value is between 0 and 1. If you want 10% then the value would be a 0.1 chance.

Below you can find the values for vanilla items for composting.

30% (0.3) 50% (0.5) 65% (0.65) 85% (0.85) 100% (1.0)
  • Beetroot Seeds
  • Dried Kelp
  • Glow Berries
  • Grass
  • Grass Block (Bedrock only)
  • Hanging Roots
  • Mangrove Propagule
  • Mangrove Roots
  • Kelp
  • Leaves
  • Mellon Seeds
  • Moss Carpet
  • Pink Petals
  • Pitcher Pod
  • Pumpkin Seeds
  • Saplings (Any)
  • Sea Grass
  • Small Dripleaf
  • Sweet Berries
  • Torchflower Seeds
  • Wheat Seeds
  • Cactus
  • Dried Kelp Block
  • Flowering Azalea Leaves
  • Glow Lichen
  • Melon Slice
  • Nether Sprouts
  • Sugar Cane
  • Tall Grass
  • Twisting Vines
  • Vines
  • Weeping Vines
  • Apple
  • Azalea
  • Beetroot
  • Big Dripleaf
  • Carrot
  • Cocoa Beans
  • Ferns (Any)
  • Flowers (Any)
  • Fungus (Any)
  • Lily Pad
  • Melon
  • Moss Block
  • Mushrooms (Any)
  • Mushroom Stem
  • Nether Wart
  • Potato
  • Pumpkins
  • Crimson Roots
  • Warped Roots
  • Sea Pickle
  • Shroomlight
  • Spore Blossom
  • Wheat
  • Wither Rose
  • Baked Potato
  • Bread
  • Cookie
  • Flowering Azalea
  • Hay Bale
  • Mushroom Blocks
  • Nether Wart Block
  • Pitcher Plant
  • Torchflower
  • Warped Wart Block
  • Cake
  • Pumpkin Pie

Item as a dispenser output

Setting name Setting description
Enable custom dispense behaviour: When checked, this will enable custom dispense behaviour.
Dispense successfully if:

This condition controls if the dispenser should dispense the item.

When the dispense condition fails the fail sound will play for the dispenser.dispenser

On dispense attempt with result: This procedure determines what happens to the item after attempting to be dispensed. If nothing is selected or the selected procedure does not return itemstack, the current itemstack used for dispensing will be shrunk in size by 1 in case of dispense success.

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