nightly 02_02_2100 and explosion damage on large units

[robin]

So I'm testing and I'm experiencing this:

EDIT: I'm testing my mod which is quite large and modifies everything, but still damage should behave normally if values are correct.[/b]

target unit specs:
- 2x2 (large)
- hp 340
- armor: 5 all around**
- explosion mod: 1.0

attack method:
- single shot (rocket)
- direct hit
- power: 80***

Damage dealt ranged from 229 to 340 (instakill).
Is this normal?

**
    frontArmor: 5
    sideArmor: 5
    rearArmor: 5
    underArmor: 5
    drawingRoutine: 5
    size: 2
    damageModifier:
      - 1.0
      - 1.0
      - 2.0
      - 1.0
      - 1.0
      - 1.0
      - 0.5
      - 1.0
      - 0.2
      - 0.0

***
  - type: STR_TANK_ROCKET_AMMO
    size: 0.6
    costBuy: 3000
    costSell: 2250
    transferTime: 48
    weight: 1
    bigSprite: -1
    floorSprite: 16
    hitSound: 0
    hitAnimation: 0
    power: 80
    damageType: 3
    clipSize: 6
    battleType: 2
    invWidth: 1
    invHeight: 3

[Arthanor]

Which damage rule do you use, EU or TftD? That will impact your results quite significantly.

The average damage should be the same though:

80 (GZ) + 3x 70 (3 other tiles) - 4*5 (the armor, for each quarter) = 270 damage.

EU rule has 100% variance before armor:
MinEU: 0
MaxEU: 290*2 = 580, -20 for armor = 560

TftD rule is 50% variation:
MinTftD: 290 *0.5 = 195, -20 for armor = 175
MaxTftD: 290 *1.5 = 485, -20 for armor = 465

Big units really need spash damage protection and/or good armor. Getting hit 4 times is really harsh. It would work much better if they had "self shielding" like objects can shield damage on subsequent tiles.

[kikimoristan]

unlike the soldiers a HWP i think is made up for 4 units that count 1/4 . So dealing area damage deals 4 x more damage . This only applies to explosives. Also I notice you have incendiary x 2 and he x 1.  With default xcom 0 to 200%  damage rule a power 80 rocket would deal a max of 2 x 4 x 80 = 640 to a 4 tile unit before armor and damage reduction applies.

The trick is adjust damage modifiers
1.0 - none
1.0 - AP no aliens use AP
2.0 - incendiary reduce this to 0.0 ..tanks should go trough fire
1.0 - high explosives reduce this to 0.2 o 0.4 as 1 alien grenade will insta kill your tank
1.0 - laser - sectopods
1.0 plasma - all aliens use this
0.5 stun reduce this to 0.0 tanks should not go unconscious
1.0 - i dunno about this ..tanks should withstand melee damage id reduce it to 0.7 or 0.8
0.2 - acid too low.acid is supposed to be that rare dangerous damage type i'd bump this to 0.8 o 0.7
0.0 - smoke - good

[Warboy1982]

tftd formula only applies to non-explosives

[Arthanor]

@Warboy: That's good to know. So explosives are always 0-200% damage?

unlike the soldiers a HWP i think is made up for 4 units that count 1/4 . So dealing area damage deals 4 x more damage . This only applies to explosives. Also I notice you have incendiary x 2 and he x 1.  With default xcom 0 to 200%  damage rule a power 80 rocket would deal a max of 2 x 4 x 80 = 640 to a 4 tile unit before armor and damage reduction applies.

robin didn't say it was a tank he was testing. Could be any kind of alien 2x2 unit too. I'm sure he knows about damageModifiers.

Damage drops by 10 for every tile and only one tile is ground zero. The max damage is thus 2x (80 + 3*70) = 580 before armor&modifiers.

[Warboy1982]

no, always 50-150. and NINE tiles are considered "ground zero", and will affect the "under" armor. there's more info about it on the ufopaedia https://www.ufopaedia.org/index.php?title=Explosions

for the most part, explosions in openxcom should function the same. (apart from things like mile-high madness)

[kikimoristan]

@Warboy: That's good to know. So explosives are always 0-200% damage?

robin didn't say it was a tank he was testing. Could be any kind of alien 2x2 unit too. I'm sure he knows about damageModifiers.

Damage drops by 10 for every tile and only one tile is ground zero. The max damage is thus 2x (80 + 3*70) = 580 before armor&modifiers.

either way lower HE or you'll get toasted fast being 4 tiles.

[Arthanor]

no, always 50-150. and NINE tiles are considered "ground zero", and will affect the "under" armor. there's more info about it on the ufopaedia https://www.ufopaedia.org/index.php?title=Explosions

for the most part, explosions in openxcom should function the same. (apart from things like mile-high madness)

Oh, that's good to know! I think I used to know but only so many things I can keep in mind

9 tiles are ground zero and hit under armor, but only one gets full damage, right? All the neighbouring tiles would get reduced damage (by 10 for adjacent tiles, by 15 for the one diagonal from the impact tile)

[robin]

I'm using EU formula but, as Warboy said, it doesn't matter for explosives.

So the cause of the high damage is the 2x2 size, which causes the unit to be hit *4* times by area-type damage:
- explosive
- fire
- stun..? (AFAIK stun uses the normal damage formula, so 0-200% in EU, but still "degrades" like explosive over the area it covers).

If this is intended (IE: not a bug), then I'll balance-tweak armor damage modifiers for 2x2 units, accordingly to this behavior.

[Warboy1982]

it's intended. otherwise we'd have had to reduce all HE armor values by 3/4 to compensate, and it wouldn't have been quite the same