HOI4 механики

HP. "HP" is an abbreviation for "hit points." This is the ability to absorb damage and is largely a function of manpower and role. Also referred to as Strength. Division HP represents how many hits or damage the division can take before it is physically destroyed. The more HP a division has, the fewer losses to its manpower and equipment it will take from the same amount of damage. When a division takes damage to its HP, its combat stats are reduced proportionally; for example, a division at half of its maximum HP can only use half of its maximum possible attacks or defences in combat.

Organization. Known as "morale" in previous games, organization is the readiness of a division to perform combat, the willingness of a unit to either continue attacking or to continue holding the province that they are defending. Once a unit no longer has any organization remaining, it can no longer fight in battles. Infantry and mobile battalions tend to be the primary source of organization in a division, so it is important to buffer lower-organization battalions like tanks and combat support battalions with enough of them to keep the division combat-capable. Moving a division causes organization loss at the rate of -0.2 organization per hour, and organization loss also slows down movement to up to -80%.

Armour. Decreases the number of soft and hard attacks made against the division if the attacking division's piercing is less than the defending division's armor, by up to -50% at less than 50% piercing. Higher armor than the enemy's piercing will also increase the number of unit attacks in combat and change the organization damage dice roll per attack from 1d4 to 1d6 as the unit can move around the battlefield more freely without getting pinned or damaged. A division's armour is equal to 40% of the highest armor in the division plus 60% of the average armour in the division. Armor is not a property of unit type, only of its equipment.
Piercing. Represents the ability of a division to pierce armour and pin down armoured forces, restricting the movement. If the value is higher than the enemy's armor value, then the division suffers no penalty to its damage and suffers no additional organization damage. Otherwise, the division deals -20% damage with at least 75% piercing, the division deals -35% damage with at least 50% piercing, and -50% damage otherwise. A division's piercing is equal to 40% of the highest piercing in the division plus 60% of the average piercing of all battalions and companies in the division.



Initiative. Higher initiative speeds up battle planning, so 20% initiative, as from a level 1 signals company, speeds up 2%/day planning to 2.4%/day. Higher initiative also increases the chance of a division joining a battle from the reserves, with each 1% initiative increasing reinforce rate by 0.25%. The stat for the division is the sum of those of all battalions and companies.

Each attack has the potential to be a hit (causes HP and organization damage) or a miss (no effect on HP and organization). After each attack, the defending unit removes one defense (if it has some left). The hit chance depends on whether the defender had any defenses left. If it did, the hit chance is 10%.Without any defenses left, the chance increases to 40%.

Divisions do not attack enemies uniformly. Each division has an "Engagement Width" of twice its own combat width, used to create a list of targets. Enemy divisions are added in a random order, rejecting any that would cause the list of targets to exceed the engagement width. If none of the enemy division fit, one is picked randomly. For example, a 36 width division has an engagement width of 72. Its list of targets could include five 14 width divisions (5*14 < 72) but if it were to encounter five 15 width divisions it would only engage four of them at a time (5*15 > 72).

The attacks are split into an uncoordinated and coordinated part. Uncoordinated attacks are spread between all targets in the engagement width according to their respective width. One selected priority target additionally receives all of the coordinated attacks, increasing the chance to overcome its defenses.
The coordinated share is 35% + Coordination × (1 + Initiative)

Надежность >95% = минимальные потери от истощения (на 80% меньше чем при 90% надежности), 90% надежности на 140 % потерь чем при 85% надежности

• Terrain: the attacker receives attack and breakthrough penalties in rough terrain, up to -50% (even more with heavy units)
  
• River crossing: penalty of -30% or -60% for attacker attack and breakthrough depending on the river size
  
• Night: penalty of -50% for attacks of both sides, mitigatable with Land Night Attack Land Night Attack bonuses
  
• Fort: penalty for attacker attack and breakthrough of -15% per fort level. Each extra attacking direction cancels out one fort level, but not the last level.
  
• Encirclement: penalty for defender -30% if all surrounding land provinces are enemy-controlled (excluding islands)
  
• Enemy air superiority: up to -35% penalty for whichever side is facing hostile air superiority
  
• Low supply: scaling attack/defense penalties up to -25%[25]/-65% and -35%/-15% for the attacker and defender, respectively
  
• Exceeding combat width penalty: -1% per extra percent of combat width, up to -33%
  Stacking penalty for having too many divisions in combat: -2% per division over the stacking limit. The stacking limit is 5, plus 3 per flanking direction.
  
• In multiple combats: -50% for a division that is in multiple combats (e.g. attacking while being attacked)
  
• Paradrop penalty: -30% combat penalty for 48 hours after being paradropped
  
• Amphibious penalty: -50%
  
• Commander skill: +2.5% per skill point for both attack and defense
  
• Planning bonus: up to +30% for the attacker, which can be further improved by a doctrine to +110% or more
  
• Entrenchment: +2% for the defender per each point built
  
• Air support: bonus to attack and defense (in addition to direct damage support planes do)
  
• Country bonus
  
• Division experience: -25% for Green Green, +0% for Trained Trained, +25% for Regular Regular, +50% for Seasoned Seasoned, and +75% for Veterans Veterans
  
• Intel advantage: up to +15% from army intel advantage (starting at 5 and maxing out at 50 intel advantage)
  
• Tactics: +20% from breakthrough as an example.

For example:

experience +75%
entrenchment +40%
terrain -40%
country +40%
commander skill +35%
results in a modifier of +456% to base stats (1.75*1.4*0.6*1.4*1.35=2,7783)

CAS damaging enemy units
The attacking planes deal (ground attack)*(number of planes) attacks against a randomly selected enemy division. An ace can increase the amount of attacks, while weather might decrease it (stacking multiplicatively). The attacks are resolved as between land units, but they ignore defense, hardness, and armor. Generals and field marshals can reduce the damage done to their units by enemy CAS with Camouflage Expert Camouflage Expert. Employed military high command characters who specialize in Concealment can also reduce the amount of damage inflicted by enemy CAS. The resulting damage values against organization and strength are scaled by 0.032 and 0.032, respectively, instead of 0.053 organization and 0.06 strength as in land combat between divisions.

Enemy units damaging CAS
Divisional anti-air (AA) weapons reduce the damage from CAS. Anti-air capabilities are averaged across all divisions including the reserve. The maximum damage reduction of 75% is already achieved at 10.8 average anti-air attack.

Additionally, the divisional AA (again using the divisions' average) has a 7% chance to shoot down a portion of the attacking planes. When it does, it can shoot down a fraction of attacking planes up to 0.5% × (air attack). The actual amount is a random value up to that portion (i.e. on average half as much) but at least one plane always gets shot down. None of the plane's attributes have an influence on the effectiveness of anti-air.