Combat Notes from the Devs
With the exception of the terrain rules (which I'll get to in a moment), the stats generally follow a common sense approach, the biggest difference from comparison with many other games is that there are "more combinations" due to target types, and more modifiers.
At the core, when all other stats are the same and you have a unit with an attack of 20, compared to a unit with an attack of 10, the first unit will do twice the damage per shot. When you have a unit with a defense value of 20, compared to a unit with a defense value of 10, the first unit will take only 1/2 as much damage when it's hit versus the second.
So this would also mean that if you had a unit with an attack of 30 versus a unit with a defense of 30, the amount of damage would be similar to if you had a unit with an attack of 20 versus a unit with a defense of 20. The formula at its core is "my attack value against your defense value".
It's the modifiers, target types and terrain rules that can make things more complex.
First is the target type - this indicates which attack value is used. A tank against another tank would use the Hard Target Attack Value, and the Ground Target Defense Value. A tank against an infantry would use Soft Target Attack versus Ground Target Defense, etc.
Next is the terrain - Low Visibility areas (dense forests, cities) create "Close Combat" situations. A unit attacking into a close combat hex attacks with its close combat attack value (instead of it's regular hard/soft attack value). A unit inside a close combat hex defends with its close defense value.
And finally, some other unit specs will modify all the values (attack/defense) - these include the strength of the unit (a tank battalion strength 40 will have twice the attack value of a tank battalion strength 20), experience, efficiency, and morale.
Units with low efficiency and morale are reported by way of a red border on their strength bar; units with improved experience show a star on their description lines.
Depending upon your strategy, other specs can also play an important role - for instance, the Initiative value (reported in the unit Technical Readout popup as "Reaction Time") generally indicates how quickly the unit reloads (how fast it fires again after firing), and the Combat Time shows how many shots it can take before it runs out of ammo (particularly important if you are in a poorly supplied area or moving forward on your front line). There is also the fact that indirect/strategic attacks can damage all units in a hex, while direct attacks are against a single target. Range is also a factor for units that can shoot more than next hex - the farther the shot, the less damage it does. Weather is another modifier, with rain, mud, snow, and frozen ground modifying both the results and also the morale of participating units.
In a formula way, this would be an example of how it's applied (though the weightings are simplified here for illustrative purposes) :
Attacking Unit Value =
[Battalion Strength] * [Attack Value] * [Efficiency] * [Experience] * [Morale]
Defending Unit Value =
[Defense Value] * [Efficiency] * [Experience] * [Morale]
So a tank Battalion with strength 40, a soft attack value of 25, attacking in clear terrain (no close combat), with average efficiency, a little bit of experience, and average morale, would be:
Attack = 40 * 25 * 1.0 * 1.1 * 1.0
So, it's attack value would be 1100
Its attack on an infantry with ground defense value 30, average efficiency, no experience, and very low morale :
Defense = 30 * 1.0 * 1.0 * 0.5
Its defense value would be 15
The number of infantry squads lost when the shot hits is: [Attack] / [Defense] / 10
So in this case: Damage = 1100 / 15 / 10
The infantry would lose approx 7 squads (7 from its strength value). This is very very approximate, like I say the formula weightings are a bit different, but it gives you the idea of how the calculations are done, and there's not much magic or hidden mysteries. Just a lot of factors to consider that can modify the results.
+1, I would like the option to choose which unit my army attacks first though, ahh that would be nice. I know I used to be able to target the unit I wanted when using bombers, but it would be cool to tell your whole ground stack to focus on a specific unit first. Example: Paradrop rangers in, take out just the AA, and have them retreat once they finish off thier target. Bombers come in after that to take care of the rest [/quote]
The AI will generally target the weakest dangerous unit in a stack and follow the suggestion above. So if a stack had 5 full strength tanks and 1 damaged tank, the damaged tank would be targeted. Units like artillery and supply trucks and AA are "stand off units", which means that they will hide and cower behind any armor and infantry, so you must take out the fighting units before you can get to shoot at the support units. This is the primary reason you can't directly target who to attack.
Artillery and air are different in that they can target directly, or in the case of indirect fire they will damage the entire hex (although one particular unit will get the "direct hit" and suffer more damage).
1) Why does Battalion Strength not factor into defense calculation?
2) Is every 'shot fired' a guaranteed hit? (this includes area attacks from artillery and missile attacks)
The main reason why the Battalion Strength is not used in the defense value is that it doesn't affect "how much damage" the attack does. While you could argue that a damaged battalion might be a bit more spread out and harder to hit, in general the concept is that each shot will do approximately the same amount of damage. So if the strength of the Infantry was 60 squads to start with in the example I gave, the first hit it takes it will go from 60 to 53 strength, the second hit will take it from 53 to 46, and so on. That's assuming the "lab controlled" situation where the infantry isn't firing back, nobody's moving, the weather is unchanged, and there's no other units around that get involved.
Which sort of brings us to the second question, in Supreme Ruler every shot is a "hit". While this isn't entirely realistic in that it removes the possibility of the "lucky hit" or the "unlikely survival", for a game of this scope it plays better and more realistically overall.SR doesn't need "random factors" in the battle calculations because of the fact that we take so many elements into account that, due to the real-time nature of the game, you can't be certain of exactly what an outcome will be to any given battle. A battle that might be an overwhelming victory could turn out completely different if you remove the air support or extra artillery that took part. But on the other hand, if you and your opponent play the exact same battle in the exact same way, you'll get the same result.
PS - One additional factor in the Attack Value calculations is whether the unit that is attacking is moving - some classes, such as Anti-Tank, Artillery, and Recon, suffer a penalty on their attack strength if they shoot while moving. Tanks and Infantry generally do not suffer this penalty.
= Close Combat System = Close Combat is a method of resolving combat that uses values more appropriate to restricted terrain. Every unit has close combat values. Close combat resolution will be triggered when one unit involved occupies a close combat hex, which are emplacements,small or above military bases, cities and towns, mountains, and dense forest. Close combat hexes may be viewed by pressing V. The terrain type of the target's hex will determine what defense values are used. Note that attack and defense values are only two of a large variety of factors involved in combat resolution. Others include initiative, suppression and morale.
Infantry generally have higher close combat values while tanks have much lower values. Be sure to avoid using tanks in close combat areas!
- Infantry in city firing on tank in city. The infantry will use it's close combat attack value and it will be compared against the close defense of the tank during combat resolution. When the tank returns fire it will use it's close combat attack value and it will be compared against the close defense of the infantry
- Infantry in city firing on tank in the open. The infantry will use it's hard attack value and that will be compared to the ground defense value of tank. When the tank returns fire it will use it's close combat attack value and it will be compared against the close defense of the infantry