Evasion

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Revision as of 05:00, 20 October 2013 by >Magnanimous2 (Citation'd and reworded for clarity)
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Not to be confused with Dodge.

Evasion is a rating that measures a character's ability to avoid being struck by enemy attacks. Evasion is opposed by the attacker's Accuracy.

All classes start with 50 base evasion rating and gain 3 additional evasion per level. The first level is included in this, so a level 1 character will have 53 base evasion. This gives a base of 350 evasion at level 100.

Dexterity also grants bonuses to evasion. Every 5 points of dexterity provides 1% increased evasion rating.

Movement speed is beneficial for characters that employ evasion as the primary form of damage reduction, since it requires a play style where physically avoiding enemy spells and attacks is often necessary.

Mechanics

Evading an attack prevents all damage and other harmful effects including status ailments and stun. Only melee and ranged attacks can be evaded; spells will automatically hit. The chance to evade an attack is based on the defenders evasion rating verses the attacker's accuracy.

   Chance to Evade = 1 - Attacker's Accuracy / ( Attacker's Accuracy + (Defender's Evasion / 4) ^ 0.8 )[1]

Chance to evade can never be lower than 5%, nor higher than 95%. The exception to this is when Cannot Evade enemy Attacks applies from the Unwavering Stance keystone or Ezomyte PeakEzomyte Peak
Iron Hat
Armour: (84-113)(15-20)% increased Area of Effect
+(75-100) to Armour
+(25-50) to maximum Life
Unwavering Stance
Centuries of servitude, a day
of glory, an eternity of death.
; this completely removes the character's chance to evade.

Evasion also gives an implicit chance to avoid taking critical strikes from attacks.[2] Critical strikes from spells can't be evaded. If an incoming critical strike succeeds its hit roll, a second independent hit roll is performed to determine if the critical is evaded or not. If this roll succeeds, a critical strike is scored. If it fails, the attack still hits, but only for regular damage.

Evasion is not purely based on chance in the sense that each hit is independent. Instead, it uses a system of "entropy" to ensure that enemies won't get long strings of hits or misses by chance.[2] To summarize, these are the calculation steps in each attack:

  • If it is first time an entity is attacked or if the time between the last attack and this one is larger than 6 seconds, randomise the entropy from 0-99.
  • Calculate chance to hit of the attacker using the above formula, and add this integer to the entropy counter.
  • If this is 100 or greater, the check counts as a hit. Subtract 100 from the entropy counter. Otherwise it is a miss and the entropy counter doesn't change.
  • A critical hit is evaded on a separate random roll and will not affect this entropy value.

This system is designed to evenly spread out hits and misses such that players always evade an average number of times according to their ‘chance’ to evade. It is still based on chance because of the entropy counter's randomization in the first step. Note that if multiple mobs are attacking one character, all of the mobs' attacks share the same entropy counter.[3] Also note that the chance to evade calculation on the character page is based on the average accuracy of a monster at the player's level.

Example

A player is fighting three monsters, one(A) with a 70% chance to hit and two(B,C) with a 45% chance to hit.

  • A attacks. The player's entropy is a random number between 0-99, in this case 37.
  • A adds 70 to the counter, raising it to 100 or greater, and hits. 100 is subtracted and the counter is now 7.
  • B attacks, adding 45. 52
  • C attacks, adding 45. 97
  • A attacks, adding 70. This hits and the counter becomes 67. It happens to be a critical strike, which means it has a 70% chance to do bonus damage. This roll is independent and doesn't affect entropy.
  • The player runs away for >6 seconds, so a new entropy value will be rolled on the next attack.

Interaction with Dodge

Chance to Dodge bonuses granted by sources like Acrobatics function similar to evasion, but are rolled separately and are pseudo-random rather than entropy-based. Phase Acrobatics grants a chance to dodge spells.

Assuming a character has a 40% chance to evade and a 20% chance to dodge, a character has a 52% chance to avoid taking damage.

Chance to Avoid Attack = 1 - ( (1 - Chance to Evade) * (1 - Chance to Dodge) )

Passives

There are passive skill nodes that grant additional evasion or a combination of bonuses including evasion.

Evasion

These passives increase evasion rating by a percentage.

In the case of Ondar's Guile, the chance to evade projectile attacks is doubled.

Icon Name Bonuses
File:Passive-evasion.png Evasion
  • 10% increased Evasion Rating

  • 18% increased Evasion Rating
File:Passive-reflexes.png Reflexes
  • 30% increased Evasion Rating
File:Passive-evasionandenergyshield.png Evasion and Energy Shield
File:Passive-nullification.png Nullification
File:Passive-armourandevasion.png Armour and Evasion
  • 8% increased Evasion Rating and Armour
File:Passive-leatherandsteel.png Leather and Steel
  • 24% increased Evasion Rating and Armour
File:Passive-frenzychargesmall.png Evasion per Frenzy Charge
File:Passive-keystone-arrowdodging.png Ondar's Guile

Miscellany

These passives are related to evasion, but don't fit into any other category.

Icon Name Bonuses
File:Passive-keystone-ironreflexes.png Iron Reflexes
  • Converts all Evasion Rating to Armour
File:Passive-keystone-unwaveringstance.png Unwavering Stance
  • Cannot Evade enemy attacks
  • Cannot be Stunned

References

  1. Mechanics Thread, post by Malice
  2. 2.0 2.1 Mechanics Thread, post by Mark_GGG
  3. Mechanics Thread, post by Mark_GGG