Armor as Damage Reduction

[TBeholder]

d100 Warhammer RP series from FFG have armor work like this. Armor Points often vary per location; also, armor has limitations (in the later games, all), and often extra stuff built in and/or special properties. Total damage soak is AP value of armor (minus the weapon’s Penetration) + Toughness Bonus of the target.
For a mediocre vs. mediocre example: common firearms and lasguns do 1d10+3 Pen 0, Guard flak armor is AP 4 anywhere (+1 vs shrapnel), a typical non-augmented human wearing it has TB 3 (4+3=7 total soak) and 10 Wounds; thus more than half of the hits inflict at least some harm, but no immediately incapacitating injuries (except critical hits, and even then not all), which is a lot better than having all hits really hurt and 3/10 incapacitate. Obviously, using cover and other ways of not being hit so much can improve life expectancy. There are also a few types of AP 2-3 low-profile armor, which is at least better than nothing.

If you don’t like flat value because body armor is not an uniform sealed sphere, take a look at Alternity (the original one, at least). But yeah, it’s yet another roll in an engine that has too many custom rolls.
Armor coverage as a part of hit location roll could work better.

In Riddle of Steel wound level = amount of successes (probability per die depends on the attack maneuver) from the attacker’s dice pool (depends on the skill and the maneuver) - successes of the defense + weapon damage value - armor. So it’s overwhelmed often, but every point matters, since combat is quite deadly and with unstable equilibrium (wounds reduce combat dice pool).
See the examples from /tg/: sup/tg/ - /tg/ Archive

 

[Thomas Shey]

If you don’t like flat value because body armor is not an uniform sealed sphere, take a look at Alternity (the original one, at least). But yeah, it’s yet another roll in an engine that has too many custom rolls.
Armor coverage as a part of hit location roll could work better.

The non-location using BRP games sometimes did this too; I remember the Stormbringer game variations had armor as a die roll.

 

[aramis erak]

d100 Warhammer RP series from FFG have armor work like this. Armor Points often vary per location; also, armor has limitations (in the later games, all), and often extra stuff built in and/or special properties. Total damage soak is AP value of armor (minus the weapon’s Penetration) + Toughness Bonus of the target.
For a mediocre vs. mediocre example: common firearms and lasguns do 1d10+3 Pen 0, Guard flak armor is AP 4 anywhere (+1 vs shrapnel), a typical non-augmented human wearing it has TB 3 (4+3=7 total soak) and 10 Wounds; thus more than half of the hits inflict at least some harm, but no immediately incapacitating injuries (except critical hits, and even then not all), which is a lot better than having all hits really hurt and 3/10 incapacitate. Obviously, using cover and other ways of not being hit so much can improve life expectancy. There are also a few types of AP 2-3 low-profile armor, which is at least better than nothing.

technically, "Critical" is what happens when you run out of wounds...
open ending on max damage rolled is called "Righteous Fury" - if you roll a 10 on any damage die, (including the simulation of d5), roll to hit again - if that hits, fury triggers, and the damage dice roll again, and add, and further 10's continue to open end without further skill rolls.

Any shot has a chance of going WAY over the top. At one point, demoing Only War, one of the PCs open-ended spectactularly enough that the description only could be, "After that pile of fire, only a geneticist will be able to ID him..." Armor has no additional effect in such, so...

 

[TBeholder]

technically, "Critical" is what happens when you run out of wounds...
open ending on max damage rolled is called "Righteous Fury"

I used the generic term because it would require an explanation for those who did not look into it. Also, depends on the game (“Zealous Hatred” in BC and apparently “additional damage” in WHFRP).

- if you roll a 10 on any damage die, (including the simulation of d5), roll to hit again - if that hits, fury triggers, and the damage dice roll again, and add, and further 10's continue to open end without further skill rolls.
Any shot has a chance of going WAY over the top. At one point, demoing Only War, one of the PCs open-ended spectactularly enough that the description only could be, "After that pile of fire, only a geneticist will be able to ID him..." Armor has no additional effect in such, so...

In some of these games, though not OW (not even in Beta, because it was changed earlier in BC). Somebody should… you know… check.
But yes, as it’s not soaked separately and PC weapons tend to be better than civilian holdouts, full damage roll on top of already maximal damage often destroys critters without ridiculous amount of Wounds and/or total soak. Which was probably why this version was errata’ed away.
Warhammer Fantasy Roleplay: confirm via (+0) WS test for +1d6 damage; if rolled 6 on extra damage, repeat without confirming.
Dark Heresy: confirm via attack roll (all modifiers of the original attack) for +1d10 damage; if rolled 10 on extra damage, repeat without confirming.
Rogue Trader, Deathwatch: confirm for extra +damage roll; if any 10 in extra damage roll, repeat. Also, in DW all PCs have “Deathwatch Training” talent, which auto-confirms RF against all aliens, even unknown, and with most common weapons having (until errata’ed) 2 damage dice, almost 1/5 hits are RF.
RT & DW errata (1.4 and 1.1 respectively): eventually this was replaced with “confirm, +1d10 damage, only once”.
Black Crusade, Only War, Dark Heresy 2: roll 1d5, look up the relevant Critical Effects chart, apply. That’s it.

Anyway, the practical advantage of both soak and save based armor mechanics vs. hit adjustment (D&D AC style) is that as separate stages of the resolution rather than being entangled with hit roll, they are easier to make work with locations. Also, better look & feel (“the attack connected… and bounced off armor”) without extra efforts.
Any of them need tinkering and analysis of extreme combinations to work well for given premises and look believable on better detail scale than wargame. Mainly to get rid of excessively easy penetration without turning any dude in a cuirass into a tank. Here soak mechanics is at a disadvantage, unless the soak value is variable to simulate armor not being an uniform eggshell, i.e. at the cost of an extra roll (like in Alternity or early Rifts IIRC).
Also, soak naturally gives partial result rather than all-or-nothing, which simulates bludgeoning damage better.
But they are entirely separate only in mechanics where a hit is all-or-nothing. If the margin of success on hit rolls affects damage, hit adjustment doubles as soak (again, Riddle of Steel).