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Explosion

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TNT exploding.

An explosion is a physical event, generally destructive, that can be caused by several different circumstances. It can destroy nearby blocks, propel and damage nearby players, entities, and their armor, and cause one or more fires. Explosions produce a "shockwave" particle effect.

Multiple close explosions may propel objects further, but have no cumulative effect on the destruction of a block. This is because explosions' damage to blocks is evaluated individually (per explosion), and blocks' blast resistance does not become "weakened" per explosion.

"Destroyed" blocks have only a 25% chance of dropping as collectible resources (and otherwise disappear), generally making explosions a poor resource gathering technique. Items that already exist as dropped collectible resources are not affected by explosions.

The propulsion effect of explosions is often used for TNT cannons.

Explosion Type Power Notes

Wither
(on creation)
7

Ender Crystal
6 May start fires

Charged Creeper
6

Bed
(in Nether or End)
5 Starts fires

TNT
4

Creeper
3

Ghast
fireball
1 Starts fires

Black Wither Skull
1

Blue Wither Skull
1 Treats blast radius blocks (except bedrock and end portal frames) as having a blast resistance of no more than 4.

Contents

[edit] Effect

[edit] Model of block destruction

1352 rays from the explosion center to points that uniformly distributed on the surface of a cube centered at the explosion with an edge length of 2. (However, this only defines their directions, not their length)
The roughly spherical pattern of blocks destroyed can be seen here.

An explosion can destroy nearby blocks. Its blast effect is evaluated independently on many explosion rays originating from the explosion center, as shown in the right figure.

  • Each ray has an initial blast force randomized in [0.7 × power, 1.3 × power].
  • The effect of the blast force is examined at checkpoints on the ray with step length of 0.3.
  • The blast force is absorbed (block resistance/5 + 0.3) × step length by the non-air block (no matter whether destroyed) at each checkpoint, and attenuated by step length × 0.75 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).

From the above process, the following results can be deduced (where ⌊x⌋ is the floor function):

  • The blast radius in the air of an explosion (i.e. only attenuated, not absorbed by blocks) = ⌊1.3 × power/(step length × 0.75)⌋ × step length = 10.2 (charged creepers), 6.9 (TNT), 5.1 (creepers), 1.5 (fireballs). For example, a TNT explosion can destroy a torch 7 blocks away. But how many blocks an explosion can destroy is non-deterministic and also dependent on the specific location of the explosion.
  • The minimum block resistance required to absorb maximum blast force of an explosion happening in nearby air = ((1.3 × power − attenuation steps × step length × 0.75)/step length − 0.3) × 5. To not be destroyed, a block has to absorb all blast force at the first checkpoint in it.
    • The attenuation steps is subject to collision restrictions. For explosion in air, there is at least one attenuation step. TNT and creeper explosion are always 0.49 and 0.5 meter away from nearest block (2 att. steps), but fireball explosion can happen anywhere (1 att. step).
    • Thus, the block resistances are 121.00 (charged creepers), 77.67 (TNT), 56.00 (creepers), 16.42 (fireballs).
    • So water, lava (Note: Only the stationary block) obsidian, and bedrock are always indestructible, and fences and less blast-resistant blocks can be destroyed by fireballs. These are theoretical values, and in reality less resistant blocks are not always destroyed, and since Minecraft is supposed to be simple, there is no such mechanic.

[edit] Interaction with entities

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

  • For each entity within the radius, define impact = (1 − distance from the explosion/radius) × exposure.
  • Apply (impact2 + impact) × 8 × power + 1 point (half-heart, so we don't have to divide by 2 everywhere) of damage to the entity.
  • Propel the entity so that its velocity increases by impact in the direction from explosion to the entity.

From the above process, the following results can be deduced:

  • Entities will always get at least 1 point of damage if they are within the radius, regardless of their explosion exposure.
  • The maximum damage that entities can take (at the explosion center with 100% exposure) = (1 × 1 + 1) × 8 × power + 1 point of damage = 97 (charged creeper), 65 (TNT), 49 (creepers), 17 (fireballs). When entities are away or covered by blocks from the explosion center, they take less damage.
  • The maximum velocity gain that an entity can obtain from a TNT explosion is 1, at the explosion center with 100% exposure.
A primed TNT AABB has directionally asymmetrical sample points (1/2.96 spacing) because of rounding.

[edit] 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 has sampling error that results in directional asymmetry of propulsion. For example, a typical TNT Cannon has maximum range in the west direction partly because the primed TNT has largest sampled exposure in that direction.

[edit] Causing fire

If the explosion has the ability, it randomly starts fires in 1/3 of all destroyed air blocks that are above opaque blocks.

[edit] Permanent lag

Permanent lag is essentially lag-fallout from an explosion, this consists of drops, liquid-physics, and increased render-complexity of the crater.

It is recommended that when making a large creative-mode explosion, one uses the command "/gamerule doTileDrops false" to stop drops from being generated by explosions.

[edit] Blast resistance

[edit values]

Block name Blast resistance

Bedrock
18,000,000

Command Block
18,000,000

End Portal
18,000,000

End Portal (block)
18,000,000

Anvil
6,000

Enchantment Table
6,000

Obsidian
6,000

Ender Chest
3,000

Flowing Water
500

Lava
500

Water
500

Dragon Egg
45

End Stone
45

Block of Diamond
30

Block of Emerald
30

Block of Gold
30

Block of Iron
30

Block of Redstone
30

Bricks
30

Brick Stairs
30

Hardened Clay
30

Cobblestone
30

Cobblestone Stairs
30

Cobblestone Wall
30

Iron Bars
30

Jukebox
30

Moss Stone
30

Nether Brick
30

Nether Brick Fence
30

Nether Brick Stairs
30

Stone
30

Stone Brick
30

Stone Brick Stairs
30

Stone Slabs
30

Iron Door
25

Monster Spawner
25

Cobweb
20

Dispenser
17.5

Dropper
17.5

Furnace
17.5

Beacon
15

Coal Ore
15

Cocoa
15

Diamond Ore
15

Emerald Ore
15

Fence
15

Fence Gate
15

Gold Ore
15
Block name Blast resistance

Hopper
15

Iron Ore
15

Lapis Lazuli Block
15

Lapis Lazuli Ore
15

Nether Quartz Ore
15

Redstone Ore
15

Trapdoor
15

Wood Planks
15

Wooden Door
15

Wooden Slabs
15

Wooden Stairs
15

Chest
12.5

Crafting Table
12.5

Trapped Chest
12.5

Cauldron
10

Wood
10

Bookshelf
7.5

Jack 'o' Lantern
5

Melon
5

Mob head
5

Pumpkin
5

Sign
5

Block of Quartz
4

Quartz Stairs
4

Note Block
4

Sandstone
4

Sandstone Stairs
4

Wool
4

Monster Egg
3.75

Activator Rail
3.5

Detector Rail
3.5

Powered Rail
3.5

Rail
3.5

Clay (block)
3

Farmland
3

Grass Block
3

Gravel
3

Sponge
3

Brewing Stand
2.5

Button
2.5

Cake
2.5

Dirt
2.5

Ice
2.5

Lever
2.5

Mycelium
2.5

Piston
2.5

Piston Extension
2.5

Pressure Plate
2.5
Block name Blast resistance

Sand
2.5

Soul Sand
2.5

Sticky Piston
?

Weighted Pressure Plate
2.5

Cactus
2

Ladder
2

Netherrack
2

Glass
1.5

Glass Pane
1.5

Glowstone
1.5

Redstone Lamp
1.5

Bed
1

Daylight Sensor
1

Huge Mushrooms
1

Leaves
1

Snow
1

Vines
1

Snow (cover)
0.5

Air
0

Carrot
0

Dead Bush
0

Fire
0

Flower Pot
0

Flowers
0

Flowing Lava
0

Grass
0

Lily Pad
0

Locked Chest
0

Melon Stem
0

Mushrooms
0

Nether Portal
0

Nether Wart
0

Piston Moving
0

Potato
0

Pumpkin Stem
0

Redstone Comparator
0

Redstone Repeater
0

Redstone Torch
0

Redstone Wire
0

Saplings
0

Seeds
0

Sugar Cane
0

TNT
0

Torch
0

Tripwire
0

Tripwire Hook
0

[edit] Typical damage radius

The player will receive damage, if within these radii of a 100% exposure ground 1-, 2-, or 4-TNT explosion, with the amount of damage labeled on each circle in the figures below.

KillRadiiGrenade1.png KillRadiiGrenade2.png KillRadiiGrenade4.png

[edit] History

Classic
0.24 Creepers were first introduced in on August 24, 2009, based on a failed pig model Notch had created.
0.26 (October 24, 2009) TNT was added.
Alpha
1.2 Added Ghasts, which shoot explosive ghast fireballs.
Beta
1.5 Creepers become charged when struck by lightning, increasing the explosion's radius and strength.
1.6 Trying to sleep in the Nether causes the bed to explode.
1.8 Explosions will now emit shockwave particles after exploding. Prior to Beta 1.8, explosions only emitted smoke.
1.9pre3 Bed and ghast explosions cause fire.
1.9pre4 Trying to sleep in the End causes the bed to explode.
Enchantment "Blast Protection" added, protecting against explosions.
1.9pre6 Ender Crystal added, an entity which sits atop of a block of bedrock. It can be destroyed with a melee or hit with an arrow or snowball, causing an explosion.
Sound Update The 'Sound Update' of November 13th 2011 gave TNT a new explosion sound.
Official release
1.3.1 12w24a Fixed explosions not pushing back players.
1.3.1 Explosions damage the player different amounts on different difficulties, and no damage is dealt to the player on peaceful.
1.4.2 12w34a Added the Wither, which shoots black wither skulls.
12w37a Wither will make a massive explosion upon its creation after its health is fully charged.
Blue wither skulls added.
12w38b New Creeper fall mechanics; Creepers will explode if they fall on the player from a certain height.
1.5 Destroyed blocks have a 1/power chance of dropping as items; previously it was a fixed 30% chance.

[edit] Trivia

  • Explosions more powerful than 100 look mostly the same from the outside, as only certain lines are used to determine if a block breaks. However, some of those lines continue underground.
  • An explosion powerful enough to break bedrock would have a blast radius of over 30,000,000 blocks. If it were an uninterrupted blast, it would cover 238,775,501.2 blocks. However, explosions only follow certain lines, not every block (see previous).
  • Any explosion going off in flowing water will apply propulsion to entities, but it will not affect any block, whether the blast resistance of that block is low or high.
  • Explosions in or under water won't emit particles.
  • Explosions can redirect projectiles including Ender Pearls.
  • Explosions can break blocks on the other side of blast-resistant blocks that survive.
  • Explosions will propel dead mobs' bodies if they go off just after the mobs dies.
  • If primed TNT explodes in a large, solid cube of stone blocks, it will create an exact 3x3x3 cube inside.

[edit] References