Evasion



Evasion ( $$e$$ ) is mechanic that allows the unit to dodge an incoming attack. When evaded, the attack gets completely nullified. This means, anything that relies on attacks to hit their targets do not trigger, which includes most attack modifiers, and on-hit effects.

Mechanics
Evasion and blind trigger upon landing an attack, which is on projectile impact for ranged units. If it triggers, the attack does not affect the evading unit at all, so that no on-attack effects are triggered.

A similar mechanic to evasion is blind. While evasion makes a unit evade incoming attacks from other units, blind makes a unit miss upon attacking other units. Just like evasion, when an attack misses to blindness, it gets completely nullified.

True Strike and Accuracy are mechanics that nullifies Evasion.

Visual Feedback
Upon missing an attack on an enemy, a red floating text appears, reading, visible to the attacking player only. The enemy, who was just missed by an attack, also sees a floating text, but in white and reading  instead. Furthermore, a missed attack does not play any of the attack impact sounds.

Melee Heroes
For melee units,

Uphill Miss Chance
The uphill miss chance is a conditional effect, that only affects ranged attack projectiles of non-flying units. It causes % of the ranged attacks to miss if the attacker is at a lower terrain level as the target. A unit is considered to be on higher elevated terrain when it is no longer visible to the player due to the terrain. This means when an enemy stands on a relatively higher ramp, uphill miss chance applies whether visible or not. It does not matter how many terrain levels difference is between them, the miss chance always stays %.

Melee units, and flying units cannot miss due to the terrain.

Uphill Miss Chance Multiplier ( $$e_{up}$$ ) is defined as



Just like evasion and blind, uphill miss chance triggers upon the attack landing (which is on projectile impact for ranged heroes), not upon finishing the attack (which would be upon projectile launch for ranged heroes). This means moving up onto an elevated area after an attack projectile has been launched may cause the projectile to miss on impact to uphill miss chance, even when both units were on the same ground level as the projectile was launched.

Evasion Sources




Items
These items passively grant the wielder evasion bonus.

Blind
Blind is a debuff that makes a unit miss upon attacking other units. Sources of blind effects stack additively with each other.

Blind Debuff Multiplier is defined as


 * $$e_{bMu} = 1 - \sum (e_{b})$$

With  being the sources of Blind.

Stacking: Evasion and Blind
Multiple sources of evasion stack diminishingly with each other, while sources of blind effects stack additively with each other and multiplicatively with evasion. The uphill miss chance stacks multiplicatively with evasion and blind. The chances of all sources of evasion and blind are determined by pseudo-random distribution.

Evade Chance ( $$P(e)$$ ) is defined as
 * $$P(e) = 1 - \prod_{i=1}^n (1-e_{i}) \times e_{bMu} \times e_{up}$$

With  being the Evasion Sources,   the Blind Debuff Multiplier and   the Uphill Miss Chance.

A more concrete way of thinking about evasion stacking is that for an attack to bypass an evasion stack and hit, the attack should bypass each source of evasion in sequence. Only if all sources of evasion fail, is the attack able to deal damage. In this way, evasion's effectiveness can be understood to be stacking multiplicatively: while the actual chance to evade is diminishing, each source of evasion increases effective HP against physical attacks more than the last due to this multiplicative nature.

Sequentially, combination of evasion sources that are individually less than 100% is also less than 100%. There are currently a few abilities that have 100% evade change, e.g. and.

Unlike evasion, combination of different blind sources can exceed 100%, rendering an affected unit unable to land any attack.

Examples
Interactions between coming attacks and Evasion.
 * Example 1

Incoming attacks to hit hero who has wielded is %, because Butterfly provides % evasion.

within the radius has  evasion. Therefore, all incoming attacks are missed within the radius.

Evasion stacks diminishingly.
 * Example 2

has level 4 and a. What's are the chances of attacks hitting her?


 * Evasion Sources: : %, : %



in this example has % chance of getting hit by attacks. Because her evasion in this example is %.

True Strike
True Strike prevents the unit's attacks from missing, negating evasion, blindness and the % uphill miss chance for ranged units. It also prevents melee attacks from missing when the target moves more than  range away before the attack. Although unable to miss, attack projectiles of a ranged units with True Strike can still be disjointed. True Strike does not work when attacking buildings. However, it works against any other unit, including wards and allied units.

Accuracy
Accuracy is a mechanic similar to True Strike. Accuracy is applied as a debuff on the target.

There are two definitions of Accuracy in the game:
 * First Definition:
 * True Strike's counterpart — While True Strike prevents a unit from missing any of its outgoing attacks, Accuracy prevents a unit from being missed by any incoming attack.


 * Second Definition:
 * Chance-based True Strike — Just like proc chances for abilities, in this definition, attacks gain a chance to ignore evasion and blind effects.

Accuracy ( $$ac$$ ) is defined as


 * $$P(ac) = 1 - \prod_{i=1}^n (1-ac_{i})$$

With  being the Accuracy Sources.

Stacking: Evasion, Blind and Accuracy
Given a unit with evasion chance $$P(e)$$ and subjected to accuracy $$P(ac)$$ as defined in above sections, final chance to hit this unit $$H$$ is defined as


 * $$H = P(ac) + \big(1-P(ac)\big)\big(1-P(e)\big)$$

A intuitive way to view this calculation: The attacks against this unit have a guaranteed $$P(ac)$$ chance to trigger True Strike and land. The portion that does not have True Strike $$1-P(ac)$$ is subjected to the combined evade chance $$P(e)$$.

Or alternatively,


 * $$H = 1 - P(e)\big(1-P(ac)\big)$$

Which can be interpreted as: The attacks have $$1 - P(e)$$ change to hit and $$P(e)$$ chance to miss. But only $$1 - P(ac)$$ of the would-be-miss attacks actually miss, because $$P(ac)$$ of those attacks are changed to hit due to True Strike.

Example, has level 4  and a, being attacked by a hero affected by , level 4  while carrying a.



Those attacks have 80.65% chance to hit Phantom Assassin. In this example, 80% of the attacks is guaranteed to hit due to True Strike. Of the 20% of the attacks that does not have True Strike, they have 3.25% chance to hit Phantom Assassin.

Or alternatively,



The attacks normally have 96.75% chance to miss. But 80% of those 96.75% of attacks is guaranteed to hit due to True Strike. So only $$96.75% \times (1 - 80%) = 19.35%$$ of the attacks will miss, which give a 80.65% chance to hit.

Patch History
Esquiva Уклонение 闪避