Difference between revisions of "Damage"
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− | + | = Overview = | |
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+ | Damage in XCOM comes in two main ways - and then there are some oddballs. The two main ways are | ||
+ | *[[Weapons (UFO Defense)|Weapon]] damage, always a shot weapon, herein called a ''firearm'', and | ||
+ | *[[explosions|Explosive]] damage, also known as ''fireworks''. | ||
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+ | ''(They're all weapons, so please pardon the 'puny' words!) | ||
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+ | Both are similar, but not identical. | ||
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+ | '''Firearms''' list their ''average'' damage in the UFOpaedia - their actual damage is a range from 0 to 2 times that amount. | ||
+ | |||
+ | '''Fireworks''' also list their ''average'' damage in the UFOpaedia - but their range is half their average to three-halves their average, at ground zero (GZ). The ''average'' amount of damage then decreases by 10 per tile away from GZ, which concordantly means that their maximum (3/2*average) decreases by 15 per tile, and their minimum (average/2) decreases by 5 per tile away from GZ. | ||
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+ | ''(this is a stub, until I get around to working in the rest of Z's explanation from Discussion - MTR) | ||
= Formula = | = Formula = |
Revision as of 08:45, 28 October 2005
Overview
Damage in XCOM comes in two main ways - and then there are some oddballs. The two main ways are
- Weapon damage, always a shot weapon, herein called a firearm, and
- Explosive damage, also known as fireworks.
(They're all weapons, so please pardon the 'puny' words!)
Both are similar, but not identical.
Firearms list their average damage in the UFOpaedia - their actual damage is a range from 0 to 2 times that amount.
Fireworks also list their average damage in the UFOpaedia - but their range is half their average to three-halves their average, at ground zero (GZ). The average amount of damage then decreases by 10 per tile away from GZ, which concordantly means that their maximum (3/2*average) decreases by 15 per tile, and their minimum (average/2) decreases by 5 per tile away from GZ.
(this is a stub, until I get around to working in the rest of Z's explanation from Discussion - MTR)
Formula
Damage to Unit = (Weapon Damage * Damage Modifier) - Armour
If the bullet does negative or zero damage, then the bullet is ignored (for damage purposes, but you still get Firing Accuracy experience if it did hit). If the bullet does damage, then there's a chance that the armour plate that it struck will deteriorate by a few points.
That's the basic idea. Let's expand on the variables a bit:
Armour: The armour section the bullet hit.
Damage Modifier: 0.5 if the unit resists and 2.0 if the unit is weak against the weapon's damage type. I'm not sure, but there's probably also a 1.0 for units that neither resist nor are weak against the bullet type.
Weapon Damage: Weapon damage will be a random number between 0 and the damage level of the weapon. In reality, all weapons do half their listed damages, on average (but see below re: damage to soldiers).
A critical hit is therefore anything above 50% to 100% of the listed damage (or 100-200% for double damage, or 25-50% for units that take half damage).
Note that X-Com units take double damage from practically every major weapon type. So the Ufopaedia damage amount should be multiplied by 2, for practical purposes. Or, looked at another way, the Ufopaedia shows average damage for soldiers.
This is for sure with AP, Laser, Plasma, and Stun Bomb. For example: rifle bullets do up to 60 points of damage to X-Com units when they're only rated for 30. At least this is true for unarmoured soldiers. No wonder your units drop like flies. I'm not too sure if armour helps reduce this to normal damage.
-- NKF, Dec 18 2003, reposted by --JellyfishGreen 16:01, 21 Apr 2005 (BST)
Damage Modifiers
Everything's 100% except the following:
Vulnerable to...
Incendiary: Reaper 170% High-Explosive: Silacoid 130% Laser: Sectopod 150% Melee: Unarmoured Soldier 120% Civilian 120% Sectoid 120% Celatid 120% Floater 120% Celatid Acid Spit: Unarmoured Soldier 160% Civilian 160% Sectoid 160% Celatid 160% Floater 160% Personal Armour 110%
Resistant to...
Armour-Piercing: Cyberdisc 80% Muton 60% Zombie 60% Incendiary: Personal Armour 80% Chryssalid 80% Ethereal 70% Snakeman 70% Tanks 40% Power Suit 0% Flying Suit 0% Silacoid 0% High-Explosive: Sectopod 80% Zombie 80% Tanks 70% Cyberdisc 60% Laser: Zombie 70% Plasma: Sectopod 80% Zombie 70% Stun: Personal Armour 90% Chryssalid 90% Power Suit 80% Flying Suit 80% Ethereal 80% Zombie 0% Melee: Tanks 90% Celatid Acid Spit: Tanks 40%
"I find it amusing that Celatids are vulnerable to their own spit" -- Danial
Example
Adapted from Zombie's kindly example:
Scenario: Beginner level Muton mission. Your soldier is carrying a normal Pistol and you want to know what is the chance that a Muton Soldier's front armor will absorb a direct hit without lowering health.
Vitals: Muton Soldier front armor = 10 Muton Soldier health = 125 Muton susceptibility to Armor Piercing ammo = 60% Pistol listed power = 26 (average)
Calculation: Max damage for a Pistol against a Muton is lowered due to susceptibility: Modified max damage = INT(26 * 2 * 60 / 100) = INT(52 * 60 / 100) = INT(3120 / 100) = INT(31.2) = 31 where 2 is the max modifier and 60/100 is the damage modifier
The range of values the Pistol can deal is 0 to 31 points of damage (or a range of 32 different values). The equation's steps are shown because XCOM's math sometimes leads to slightly unexpected values in subsequent steps.
The Muton Soldier has a front armor rating of 10. It will absorb up to this much damage without changing health. In other words, it will negate the first 10 points of damage a Pistol can dish out (0-10; 11 possible values). Since the Pistol's range is 32, the probability that a direct hit will be blocked by Muton armor is simply 11 / 32 = 34.4%.
Okay, say you want to know the probability of doing damage to a Muton's health. Weapon range of the pistol is still 32, but instead of absorption we want penetration. 10 points of damage is absorbed, so we need at least 11 to penetrate. 32 - 11 = 21 values which will breach. 21 / 32 = 65.6%.
21 is also the maximum number of damage points which might be deducted from the Muton's health. Assuming the Muton was initially uninjured, in the worst case (for him!) he will have an ending health of 125 - 21 = 104.
On average, there will be 15.5 damage dealt (0-31). Then armor (10) reduces this to an actual (penetrating) average damage of 7.67.
Armor vs. Health Damage
Health and Armor Damage have a very simple relationship:
Health Damage = 10 * Armor Damage, minus 1 to 10 Or the other way around: Armor Damage = INT( Health Damage / 10 ) + 1
In table form:
Armor Health Damage Damage Min Max 0 0 0 1 1 9 2 10 19 3 20 29 4 30 39 5 40 49 6 50 59 7 60 69 8 70 79 9 80 89 etc.
Of course, this assumes armor is not zeroed out by the hit. Also note that you will always have armor damage if you have health damage and vice-versa.
This has been seen for a wide variety of explosions and some light weapons vs. Mutons, and some hits on soldiers. It has not otherwise been widely tested, but is presumed true unless/until found otherwise.
It is possible for hits (guns or explosions) to do zero damage. You still get an experience point toward Firing Accuracy if this happens.