Battle mechanics and formulas

From HOI2Wiki

Evaluation of battle

The description how battle is evaluated step by step (NOTE: not finished)

Army A (composed of units A1,A2...) attacks army D (of D1, D2..)
all modifiers (ground, weather, river crossing, encirclement, ESE, command ..) are evaluated
combat events such as Surprise and Breakthrough are evaluated where applicable
Every unit of army A randomly chooses a unit to target from B and vice versa
All units targeting unit D1 sum their attack values (see softness)

if the attack_sum = Attack_1+Attack_2... > Defence_1 than D1 gets 2*attack_sum - defence_1 hits else (i.e attack_sum < Defence_1 ) D1 gets just attack_sum of hits

In each round of the battle the organisation of the unit is decreased by the number of hits it takes
If organisation of a unit reaches zero ( 0 ), the unit stops attacking
The army loses the battle as soon as no units can fight (? - or below 5 org maybe)

Probability of events

Breakthrough
Surprise

Softness

attack = (hard_attack * (1-softness) + softattack * (softness))

Battle winning ability

In the approximation that attack affect just morale, the battle value of soldiers could be evaluated as:

BWA = attack * organisation

attack affects the rate in which unit will lower the organisation of enemy organisation determines the time the unit can withstand a given attack (time under constant attack deceasing its ORG)

more info: http://www.europa-universalis.com/forum/blog.php?b=184