Explosion

File:Tntgif.gif

An explosion of a block of primed TNT.

An explosion is an active event where an entity detonates and blows up. In the process, this destroys most types of blocks, as well as cause injury to most other nearby entities, including the player, if they are within the blast range. Explosions also propel nearby entities (including the player) away from the center of the blast. Certain explosions have the ability to create fire, such as the ghast fireball, and beds in either the Nether or the End if one attempts to use it.

Causes

Explosions can be caused by:

• A TNT block
• Creepers and charged creepers
• Beds if one attempts to use it while in any dimension other than the Overworld
• Ghast fireballs
• Wither projectiles, as well as the initial explosion when summoning the Wither
• Breaking an Ender crystal
• Using the /summon command by doing /summon TNT to blow up the area where the player is, if /summon TNT ~ ~ ~ is used, but it will blow up the coordinates used (example: /summon TNT 63 83 73)
• Respawn anchors if one attempts to use it while in any dimension other than the Nether

Properties

• Position. A TNT explosion happens at the center of a primed TNT which is a 0.98 × 0.98 × 0.98 cube. A bed explosion happens at the center of the bed block (not destroyed before the explosion).
• Ability to generate fire. The only types of explosions that can generate fire are beds and ghast fireballs.
• Power. The power level of each type of explosion is as follows (from weakest to strongest):
  • 1 - Ghast's fireball
  • 2 - Wither skull projectiles
  • 3 - Creeper explosions (not charged)
  • 4 - Primed TNT
  • 5 - A bed when one attempts to use it in any dimension other than the overworld
  • 6 - Charged creeper explosions
  • 7 - Ender crystals
  • 8 - The initial blast when summoning the Wither
  • 9 - A firework with a firework star

Through the use of commands, it's possible to create entities such as primed TNT and ghast fireballs with a larger explosion power.

Effects

Model of block destruction

An explosion can destroy nearby blocks. The damage done depends on a ray system.

• A cube around the explosion epicenter is made and divided into a 16x16x16 grid. A ray is drawn from the center to each outer cube, resulting in 1,352 rays.
• Each ray has starts out with a blast force between 0.7x power and 1.3x power.
• The effect of the explosion is examined at various intervals on the ray with a step length of 0.3.
• The blast force is lowered by (block resistance / 5 + 0.3) times the step length by the non-air block (regardless of if the block was destroyed) at the every checkpoint, and further weakened by step length x0.75 between checkpoints, until completely absorbed or attenuated.
• A block is considered destroyed if it can't completely absorb the blast force at any checkpoint in it (air blocks can be destroyed too).

The following results can be derived from the above:

• The blast radius that is not absorbed by any blocks (in the open air) is equal to [1.3 * (power)]/(step length*.75)*step length. This gives the radius of an explosion not blocked by any blocks.
  • Blast Diameter:
    • The Wither's spawn blast has a range of 12.1 blocks
    • Charged creepers: 10.2 blocks
    • Ender crystals: 10.2
    • Non-Overworld beds: 8.6
    • Primed TNT: 6.9
    • Normal creepers: 5.2
    • Ghast fireballs: 1.5
    • Both variants of wither skull projectiles: 1.5
• The minimum block resistance required is a similar equation given by the [(blast radius) * (5)]. For a block to not be destroyed, it must absorb all of the blast force (i.e. have enough blast resistance) of the explosion.
  • Block Resistances:
    • 142.67 - Initial Wither summon blast
    • 121.00 - Charged creepers & Ender crystals
    • 99.3 - Non-Overworld beds
    • 77.67 - Primed TNT
    • 56.0 - Normal creepers
    • 16.42 - Ghast fireballs & wither skulls (Only the black variant)

By normal means, lava, water, obsidian, End portal and bedrock are indestructible by explosions, all their blast resistances are over 500. Note: explosions do not have a cumulative effect on blocks. Multiple explosions at once will not destroy a block with a higher blast resistance than the initial blast. Blocks do not have "temporary health" and don't manage damage from explosions, and the status of the block is monitored independently on each new explosion, not cumulatively.

Note: Destroyed blocks only have a 30% chance of being dropped as an item.

Effects on Entities

An explosion has different effects on entities than blocks. Entities are damaged and propelled by an explosion if any are within its damage radius of 2 × power. Note that the "damage radius" is different from the blast radius of explosion effect on blocks.

• All entities within the radius, define impact = (1 - distance from the explosion / radius) × exposure.
• Applies (impact² + impact) × 8 × power + 1 point (half-heart to simplify the equation) of damage to the entity.
• Propels the entity so that its velocity increases by impact in the direction from explosion to the entity.

Based on the above processes, the following can result:

• Entities will always be damaged by at least 1 point of damage if they are within the damage radius, regardless of their exposure to the explosion.
• The highest amount of damage that entities can take (at the explosion center with 100% exposure) = (1 × 1 + 1) × 8 × power + 1 point of damage = 113 (56.5) (summoning wither), 97 (48.5) (charged creeper, ender crystal), 81 (40.5) (bed Nether/End), 65 (32.5) (TNT), 49 (24.5) (creepers), 17 (8.5) (fireballs, wither skull). When entities are far enough away or there are blocks between the entities and the explosion from the explosion center, they will take less damage.
• The highest gain in velocity that an entity can obtain from a TNT explosion is 1, at the center of the explosion with 100% exposure.

Different damage effects will ensue. For example, existing items will be destroyed, and the armor on a player will absorb part of the damage. Items dropped in the process of or after the explosion are not affected because they had no interaction with the explosion.

The propulsion effect is often used for TNT cannons.

Calculation of explosion exposure

Explosion exposure is simply how much an entity is visible from the explosion center and is approximated with the ratio of visible sample points on the entity. The approximation algorithm can have errors that affect the propulsion's directional asymmetry. For example, a typical TNT cannon has a maximum range towards the west due to primed TNT having the largest exposures sampled were towards the west.

Causing fire

If the explosion can cause fires, it will randomly start fires in approximately 1/3 of all destroyed air blocks that are above opaque blocks. This is bugged and doesn't occur in versions Beta 1.6 - Beta 1.8.

Blast Resistance

Block Name	Blast Resistance
Bedrock	18,000,000
Enchantment Table	6,000
Obsidian	6,000
Lava	500
Water	500
End Stone	45
Bricks	30
Stone Brick	30
Cobblestone	30
Block of Diamond	30
Block of Gold	30
Block of Iron	30
Jukebox	30
Mossy Cobblestone	30
Nether Brick	30
Nether Brick Stairs	30
Nether Brick Fence	30
Stone Stairs	30
Slabs	30
Stone	30
Iron Bars	30
Iron Door	25
Monster Spawner	25
Dispenser	17.5
Furnace	17.5
Coal Ore	15
Diamond Ore	15
Wooden Door	15
Fence	15
Gold Ore	15
Iron Ore	15
Lapis Lazuli Block	15

Block Name	Blast Resistance
Lapis Lazuli Ore	15
Redstone Ore	15
Wooden Stairs	15
Wooden Planks	15
Chest	12.5
Crafting Table	12.5
Wood	10
Bookshelf	7.5
Jack o' Lantern	5
Melon	5
Pumpkin	5
Sign	5
Note Block	4
Sandstone	4
Wool	4
Rail	3.5
Clay Block	3
Farmland	3
Grass	?
Gravel	3
Cake	2.5
Sponge	3
Dirt	2.5
Ice	2.5
Lever	2.5
Mycelium	2.5
Pressure Plates	2.5

Block Name	Blast Resistance
Sand	2.5
Soul Sand	2.5
Stone Button	2.5
Cactus	2
Ladder	2
Netherrack	2
Glass	1.5
Glowstone	1.5
Bed	1
Leaves	1
Snow Block	?
Snow	0.5
Seeds (Item)	0
Flowers	0
Fire	0
Mushrooms	0
Portal	0
Redstone Wire	?
Redstone Torch	0
Redstone (Repeater)	0
Sugar Cane	0
Sapling	0
TNT	0
Torch	0
Flowing Lava	0
Flowing Water	500
Air	0

Typical damage radius

A player will be dealt a certain amount of damage if these radii are within an area of a 100% exposure ground 1-, 2-, or 4-TNT explosion.

Trivia

• An explosion powerful enough to break bedrock would have a blast radius of over 30,000,000 blocks, which is enough to destroy the entire world in 1.8 or later. An uninterrupted blast would cover 238,775,501.2 blocks.
• Prior to Beta 1.8, explosions produced smoke particles.
• Explosions can lift a player into the air to a height that is high enough to cause fall damage, making creepers and charged creepers dangerous in more than just initial damage dealt.
• Explosions from things like TNT or creepers will not break any blocks if the blast occurs in water, as explosions from ender crystals will not break any blocks at all.