How does the magic work?

[Puzz3D]

You have units each composed of many men. When a man gets close to an enemy man they fight by taking turns striking at each other. This is called a combat cycle. Most men only have one hit point, but some have two and the general will have more than that. A calculation is made on each strike to see if it is a hit. When a man gets to zeo hit points (which is a single hit for most cases), the man dies. We don't know the exact algorithm being used in RTW to calculate chance of a hit in the combat cycle. STW and MTW used:

chance to hit = 1.9% * 1.2 ** (attack - defend + bonus)

where attack is the striker's attack value, defend is the target's defend value and bonus is the sum of any combat modifiers that apply to the situation. There are many situational combat modifiers. The chance to hit is compared to a uniformly distrbuted random number in the range 0 < n < 1. If chance to hit exceeds n, you get a hit. In STW and MTW, men always get to strike once within a combat cycle. A single man could parry multiple strikes from several men in one combat cycle, but only strike at one of those men.

I believe the algorithm in RTW is the same as used in STW and RTW, but the constant 1.2 is now 1.1, and there is a new "lethality" parameter for different weapon types that modifies the chance to hit. In STW and MTW, the system cutoff at - 20 and + 20 points difference which is very close to 1% and 99% chance to hit. The cutoff points will be different in RTW because each point apparently represents a smaller step on the chance to hit scale so you have more points covering the 1% to 99% range.

Ranged units shoot a projectile on a trajectory which is governed by a simple vacuum physics gravity model. Accuracy is a small random error placed on the initial trajectory. I believe lethality in this case is the projectile's ability to penetrate armor. A target's armor rating is used to calculate the probablility of a penetrating hit using a simple linear calculation and comparing the result to a random number as with melee combat. I think penetrating hits always reduce the hitpoints of the target. Some weapons such as artillery have a power parameter larger than 1 which means they can remove more than one hit point at a time.

Morale is a unit wide condition. Each unit has a starting moral and can gain or loose morale depending on its combat situation such as casualties, condition of the general and positioning relative to friendly and enemy units. If morale drops below a certain threshold, all the men in the unit rout. Lots of factors affect morale and they are deterministic in that random numbers are not used in the calculations.

Fatigue is a unit wide condition. Fatigue reduces a unit's combat points, morale and movement speed. The stamina and heat parameters modify the fatigue rate which varies depending on whether the unit is standing, walking, running, charging or fighting. There is a recovery rate which allows units to come back up to a less fatigued state. Standing is the fastest way to recover, but you might notice some recovery while walking with very fatugued units. Fatigue is also deterministic with no random differences entering the calculation.

Creative Assembly has yet to make known either the combat algorithms or the combat situational modifiers used in RTW. They did this for the previous battle engine used in STW and MTW.