Combat system for newbies

[zook08]

Combat FAQ

I'm not going to put it all down, just trying to get the ball rolling. It's incomplete and some of it is probably plain wrong. Add what you think is necessary to understand the system, or correct me where I'm wrong.

I'm using the numbers from the random game masterfile. Keep in mind that custom-made scenarios can change about every unit attribute, define new types and also change some combat mechanisms.

(Hint: if yo want to see some of these numbers in action, look at lastbattle_Log.txt in your Advanced Tactics/bin folder)

Example units:

Rifle Infantry
Type: Infantry
Role: Front Line
Hit Points: 100
Attack vs. Infantry: 13
Defense vs. Infantry: 26
FavTries: 3
Initiative Attack: 5
Initiative Defense: 5
Attacks: 1
MaxAttacked: 5
Kill%: 25
Retreat%: 25

AT Gun
Type: Artillery
Role: Rear Area
Hit Points: 200
Attack vs. Infantry: 60
Defense vs. Infantry: 60
FavTries: 10
Initiative Attack: 5
Initiative Defense: 30
Attacks: 3
MaxAttacked: 10


The Basics
Combat lasts for 10 rounds, or until one side is destroyed or has retreated. In very rare cases, it can last up to 12 rounds, I can't remember why and am too lazy to look it up.

Initiative:
Each unit type (subformation type) has different Initiative ratings for attack and defense. Higher Initiative goes first.

Target selection:
When a unit fires, the target is selected semi-randomly: the unit selects X (X = FavTries) random targets from the enemy's Front Line and then fires at the one with the highest Favourite rating, i.e. target priority for that type (you can't see this number in-game but in the scenario editor). For example, an AT gun gets 10 random target picks per attack and has a higher Fav rating for tanks than for infantry. If it picks Rifle, Rifle, Rifle, Rifle, Rifle, Light Tank, Bazooka, Rifle, Rifle, Rifle - well, it'll fire at the tank. If it picks only Rifles, it will fire at one of those Rifle units.

That means: the more cheap-o Rifle you bring to a fight, the smaller the chance that your expensive killer tanks are targeted by the gun. But guns have 10 FavTries, meaning they are quite good at picking the right target. Also, this process is done for each attack (?) and each round. Since guns can fire three times per round and have 10 FavTries per attack, they will find their targets most of the time.

Hit Chance:
Each unit type has Hit Points and a Hit Chance, based on target type and whether it is attacking or defending. When it's the units's turn to fire, two random numbers are generated: one attack roll (a number between 1 and the attacking unit's Hit Chance) and one defense roll (a number between 1 and the defending unit's Hit Points). If the attacker's roll is higher, he scores a hit.

These numbers are modified by Readiness (1-100%), Experience (1-100%), Terrain (0-???%), Entrenchment (1-200% ?).

BTW, Terrain modifiers are different for each unit and different for attack and defense. They are hidden (very well hidden) in the rightmost tab of the unit attribute screen: "Vs. SFTypes / Vs. Classes / Foot (or other movement type)". You'll find a lot of important information there. For example,

Let's say a Rifle is firing at another Rifle. Defender is 50% entrenched, both have 100% Readiness and 40% Experience, no Terrain modifier.
The attacking rifle has an unmodified attack value of 13, plus 40% for experience makes 18.
The defending rifle has 100 Hit Points, multiplied by 1.4 (40%) for experience, multiplied by 1.5 (50%) for Entrenchment, makes 210.
The attacker rolls a number between 1 and 18, the defender rolls a number between 1 and 210. If the attacker's number is higher, it's a hit.

Some units can fire more than once per round. Rifle fires only once, AT guns fire three times.

You'll notice that infantry doesn't kill a lot. It fires only once and has lousy hit chances. Also, it is much better at defending than attacking. Why buy infantry then? It's cheap. It can entrench. And it soaks up enemy fire. Each shell fired at your infantry is a shell that doesn't hit your tanks.

Damage:
A hit can cause of of three things to happen: a kill (unit attribute: Kill%), a retreat (Retreat%) or a Readiness loss. Our rifle hit has a 25% chance to kill the enemy unit, 25% to make it retreat, that leaves a 50% chance for a Readiness loss. Retreated units lose Readiness and are out of the fight, Readiness loss means they will fight on, but with decreased effectiveness (because hit chance and hit points are modified by Readiness). Oh, and kill chances are further modified by target type (the "Vs. SFTypes" tab): a machinegun has a x0.02 modifier versus Light tanks, x0.01 vs. Medium tanks and 0 versus Heavy Tanks. In other words, the MG can only make the heavy tank retreat or cause it to lose readiness; it can never kill it.

Breakthrough:
You might have noticed that units are classified as either Front or Rear. Usually, only units in the Front line can be hit, but every unit, including Rear units, can fire. That means your AT gun is protected by the infantry in the Front line. Your bombers are protected by fighters. To hit them, you have to break through the front line. The exact mechanism is a bit more complicated (read the manual if you like) and I'm writing this from memory, but basically, the game remembers how often each of the attacker's units was fired at this round. It doesn't matter if it was hit, it's only important that somebody shot at it. If a unit was not fired at for some time (two rounds?), it has broken through the front line and can now wreak havoc in the rear. These units are colored yellow in the combat screen.

That means: always bring some cheap rifles. Even if their hit chances are ridiculous, they fire can prevent breakthroughs!


Example: AT Gun vs. Lt. Tank

Just to see what all the numbers mean in the game, let's ask: what's the best unit for killing tanks?
A Light Tank has 3000 Hit Points.
The AT Gun has 450 attack points vs. tanks when attacking, but 1350 when defending. It attacks three times per round and costs 1000 points.
The Rifle has 60/60 Att/Def versus tanks, attacks once per round and costs 100 points.

Forget Rifles. Chances for a hit are 60:3000 (modified by XP, Entrechment, Readiness etc.). That's a 2% chance, once per combat round. Even though you can buy 10 Rifles for every gun, the gun has a 15% chance against tanks when attacking and a whooping 45% when defending. And it fires three times per round. And it has an initiative of 30 when defending, not 5. And it's a Rear Area unit and can't be hit unless the enemy breaks through.

Now look at the Bazooka. 250/400 Att/Def vs. Tanks, fires once, costs 250. Sounds good. But... that's a 8/13% hit chance against a light tank, once per turn. Compare that to the gun's 15/45% and the gun's rate of fire of 3. I know, mathematically you can't just add up probabilities, but to keep it simple: the AT gun gives you 3x45% = 135% for a thousand bucks, the Bazooka gives you 1x13% for 250 bucks. It's a Front line unit, low initiative. The gun can kill infantry, the zook... not really. OK, it uses only 2 Supply/turn, the gun needs 6. But why buy them at all?

Simply because with the Zook, you can equip all your units with a little anti-tank power, even if it's not much. And it weighs only 1 point, not 10, so you don't need a lot of transport. For static defense against tanks - buy guns. For defending your mobile units from tanks - buy a few zooks, maybe, maybe. IMO, it's not worth it. And for attacking enemy tanks - buy tanks or dive bombers.


In the end, this game is all about combined arms. Always bring the right tool for the job and don't misuse your tools. You have an army of specialists. Riflemen are experts at being killed in large numbers, but even that is not without its merits because you always need an infantry screen. Mortars are experts at killing infantry on the attack (100/50 Att/Def). MGs are experts at killing infantry on the defense (90/270). AT guns are experts at killing tanks on the defense. Tanks are experts at killing everything and surviving the return fire, they are even better at sucking your war chest dry.

[Daniel_machinegun]

great post! I just took notes.

[Joshuatree]

Thx Zook.. say, are you for hire to write the next much improved manual? [;)] 

[swetiger]

Nice post! [:)]

[SSFSX17]

One minor correction - combat might last for 11 or 12 rounds because some SFTypes can move very fast. In particular, Fighters, Light Tanks and Scouts can fight for less than 10 AP per round.

[zook08]

ORIGINAL: SSFSX17

One minor correction - combat might last for 11 or 12 rounds because some SFTypes can move very fast. In particular, Fighters, Light Tanks and Scouts can fight for less than 10 AP per round.

I thought it was always 10/round. What's the actual cost - the AP cost for entering the hex?

[SSFSX17]

Taking Light Tanks as an example, Light Tank IV can move for 8 AP per hex. High-level Fighters spend even less AP per hex.

Still, if it takes 10 AP to fight, that's still not enough AP saved to fight for 11 or 12 rounds. I'm thinking that the maximum AP it takes to fight is 10 AP, and some SFTypes can fight for less than that if they have a high enough "MoveRedux" bonus.

[Vic]

Actually only 10 rounds are fought, but if the defender retreats in round 10 then there are still 2 rounds of receiving fire that are calculated. You should not see round 11 or 12 fights where the defender hold the hex.
 
kind regards,
vic

[Jeffrey H.]

I enjoyed reading this, thanks Zook. I especailly like your sprinkled in sarcasm.

Thanks for the tip on the combat log file.

[balderwfr]

In Lastbattle_log

ATTACKER: Light Tank IV attacks Machinegun
BEFORE MOD: Attval= 82, DefVal= 100
Attval after global combat modifier (wheater): 82
Attval after CombatMod for Landscapetype: 82
Attval after CombatMod for Staff ( 1): 82
Attval after Rdn mod: 82
Attval after AttackMod / DefensiveMod mod: 82
attval after SupplyConsume mod: 82
Attval after Battle For People X mod: 82
Attval after Battle Versus People Y mod: 82
Attval after XP mod: 131.2
Attval after Concentric Bonus ( 1.125): 147.6
Defval after Rdn mod: 51
Defval after SupplyConsume mod: 51
Defval after Entrench mod for defending hex: 51
Defval after xp mod: 80.07
defval after Crowding def Mod: 80.07
attval after Crowding att Mod (50%) ( 0.7231969): 106.7439
AFTER ALL MODS: Attval= 106.7439, DefVal= 80.07
, Results in RETREAT, + 4 AntiStruc Dam

Attval>Defval : Result is Ok.

but here,

COMBATROUND = 1
Attack SubRound = 1
ATTACKER: Light Tank IV attacks Rifle
BEFORE MOD: Attval= 82, DefVal= 100
Attval after global combat modifier (wheater): 82
Attval after CombatMod for Landscapetype: 82
Attval after CombatMod for Staff ( 1): 82
Attval after Rdn mod: 82
Attval after AttackMod / DefensiveMod mod: 82
attval after SupplyConsume mod: 82
Attval after Battle For People X mod: 82
Attval after Battle Versus People Y mod: 82
Attval after XP mod: 131.2
Attval after Concentric Bonus ( 1.125): 147.6
Defval after Rdn mod: 85.5
Defval after SupplyConsume mod: 85.5
Defval after Entrench mod for defending hex: 146.205
Defval after xp mod: 188.6044
defval after Crowding def Mod: 188.6044
attval after Crowding att Mod (50%) ( 0.7231969): 106.7439
AFTER ALL MODS: Attval= 106.7439, DefVal= 188.6044
, Results in PINNED , + 8 AntiStruc Dam

however Attval < Defval [X(]
I don't understand.

Why ?

[Vic]

After all mods the attval and defval are used as the maximum score in a randomize operation.

on average 106 vs 188 would be a miss, but if the attacker has a good random score and the defender not the attacker will still hit.

[Jeffrey H.]

He's attacking an unentrenched mg in one attack and then a well entrenched rifle in the other attack. I think those are the main factors which result in the two attacks having a differene in defense value.
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