Forge Blocks

Blocks

Blocks make up the Minecraft world: terrain, structures, machines.

Creating a block

Basic blocks

Simple blocks need no custom class — instantiate Block with a BlockBehaviour$Properties (via #of) and chain:

• strength(hardness, resistance): hardness controls break time (stone 1.5, dirt 0.5; −1.0 = unbreakable like bedrock); resistance controls explosion resistance (stone 6.0, dirt 0.5).
• sound(SoundType): punch/break/place sounds.
• lightLevel(state -> value): light emission 0–15.
• friction(value): slipperiness (ice 0.98).

Blocks have no creative tab setter (handled by BuildCreativeModeTabContentsEvent when a BlockItem exists) and no translation key setter (generated from the registry name via Block#getDescriptionId).

Advanced blocks

For functionality (interaction, etc.), subclass Block.

Registering a block

A registered block has no item automatically. Create a BlockItem (registry name matching the block) to hold it in inventories; Block#asItem retrieves it (returns Items#AIR if absent). A Block without a BlockItem exists (e.g. minecraft:water).

Register all blocks; for config-disabling, disable the crafting recipe or use a FeatureFlag in the creative tab instead of skipping registration.

Block States

The metadata system (pre-1.8) was replaced by the block state system (1.8+). Each block property is a Property<?>; a Block + property-value map = a BlockState (e.g. minecraft:stone_button[facing=east,powered=true]).

BlockStates are immutable; all combinations generate at startup, so keep properties minimal — a rule of thumb: if it has a different name, it should be a separate block (chair direction = property; wood types = separate blocks).

Implementing

• Create static final properties: IntegerProperty#create(name, min, max), BooleanProperty#create(name), EnumProperty#create(name, enumClass), DirectionProperty#create(name, plane/axis). Reuse BlockStateProperties vanilla properties where possible.
• Override Block#createBlockStateDefinition(StateDefinition$Builder) and #add(...) every property.
• Set the default state via Block#registerDefaultState(BlockState) in the constructor (see DoorBlock).
• Override Block#getStateForPlacement(BlockPlaceContext) to choose the placed state.
• Read/write states via BlockState#getValue/#setValue, Level#setBlockAndUpdate/#getBlockState; compare with == (reference equality is valid).