Armor Class Below -10?

Wakukee

I was under the impression that AC maxed out at -10, but I just got a character down to -11. Is there a benefit to this? Thanks!

Sceptenar

The lower it gets the harder you are to hit. My tank in Icewind Dale has an AC of -17 and he is basically unstoppable.

AC is like playing limbo basically. You want to go as low as you can.

JuliusBorisov

In fact, you can go much further than that:

Potion of Defense = 0 AC
Dexterity 25 (from several potions of Mind Focusing that give +3 DEX each) = -6
Helm of the Trusted Defender = -9
Ring of Protection +2 = -11
Any shield that gives +4 (for e.g., Orrick's Rhino Beetle Shield) = -15
Battle Axe +2: Defender = - 17
Any boots that give +1 = -18
Mithran's Cloak = -21
Blur (if your fighter is partly a mage) = -24
Improved Invisibility = -28
Protection from Evil = -30
The War Chant of Sith = -32
Defensive Harmony = -34

wubble

It mainly helps to have really low AC for the enemies in throne of Bhaal as they have pretty good thac0 and can hit you even with a decent AC.
In my opinion it's what allows sword and board to compete with the other fighting styles as with a shield bonus you almost never get hit in melee and are completely un-hittable by missile weapons, thereby allowing you to walk into a fight and get attacked by everything while your other party members destroy everything.

Seldar

I have -15 in Icewind Dale without any potions and/or buff. And he is unstoppable, except in HoW by some rare enemies...

But in BG series, even with this vey low AC, I get hit by a lot of enemies. They are more powerful than in IW, like Drows, Demons, extra-planar etc...

moody_mage

Wakukee said:

I was under the impression that AC maxed out at -10, but I just got a character down to -11. Is there a benefit to this? Thanks!

In PnP - yes. In video games you can go way lower.

Wakukee

decado said:

Wakukee said:

I was under the impression that AC maxed out at -10, but I just got a character down to -11. Is there a benefit to this? Thanks!

In PnP - yes. In video games you can go way lower.

So is there a chart somewhere to look at? Does 1 lower AC mean they need 1 better to hit you?

Anomaly

This is what it means. But every natural 20 is a guaranted hit, even if your target has -100 AC.

TJ_Hooker

Wakukee said:

I was under the impression that AC maxed out at -10, but I just got a character down to -11. Is there a benefit to this? Thanks!

I'm not sure, but I think there may have been a cap of -10 or so in vanilla BG1. But now that everything's been ported to the BG2 engine, you can definitely go lower. I'm not certain that there still is a cap, but if there is I think it's low enough that it's unlikely you'll run into it.

wubble

it's linked to thac0 which is to hit armour class 0, this means that if you have an armour class 0 and if an enemy has a thac0 of 5 they need to roll a 5 or greater to hit you , however if you have an armour class of -10 the enemy must roll 15 or greater to hit you.
put simply thac0 - AC = roll needed to hit

bear in mind though that a roll of 1 is always a critical miss and a roll of 20 is always acritical hit regardless of thac0 or armour class

atcDave

Wakukee said:

decado said:

Wakukee said:

I was under the impression that AC maxed out at -10, but I just got a character down to -11. Is there a benefit to this? Thanks!

In PnP - yes. In video games you can go way lower.

So is there a chart somewhere to look at? Does 1 lower AC mean they need 1 better to hit you?

Its more a formula than a chart. Each "1" is about a 5% change. In PNP you roll a d20; and if you exceed your Thac0 minus the target's AC its a hit. So within the standard range of needing a 1 to 20 to its exactly a 5% increment for each modifier to hit or armor class. But at the extremes, you need to know a 20 always hits and a 1 always misses (5% chance of hit or miss regardless of AC or Thac0 extremes).

With regards to limits; core 2E rules set a limit on AC from -10 to 10. But this is widely ignored. Mathematically there's no reason for the limit. Especially since there is always the chance of a hit or a miss. So most DMs, like the IE games, allow for unlimited progression above and below on AC.

Gotural

The AC cap in Baldur's Gate and Baldur's Gate II is -20 base AC, then you can add your Dex modifier for a total of -26 AC. That's the maximum you will see on your character sheet, but AC modifiers (from items, like armors protecting better against specific types of attacks) still work, but they are never displayed on your character sheet.

ryuken87

Gotural said:

The AC cap in Baldur's Gate and Baldur's Gate II is -20 base AC, then you can add your Dex modifier for a total of -26 AC. That's the maximum you will see on your character sheet, but AC modifiers (from items, like armors protecting better against specific types of attacks) still work, but they are never displayed on your character sheet.

You can also get the bonus from single weapon fighting style on top of that.

Gotural

Then -28 should be the best AC one can see on his character sheet, thanks for the info @ryuken87‌ !

oldlamehand

Who cares about AC? :-) In many combats, I'm successfully tanking with mages. :-D

sarevok57

oldlamehand said:

Who cares about AC? :-) In many combats, I'm successfully tanking with mages. :-D

absolute immunity is a wonderful thing isnt it?

oldlamehand

You don't need absolute imunity. On insane difficulty even low level mage with mirror image and stoneskin survives more melee attacks than any fighter.

wubble

oldlamehand said:

You don't need absolute imunity. On insane difficulty even low level mage with mirror image and stoneskin survives more melee attacks than any fighter.

depends on the fighter if you go sword and board you can quite easily get to -17 AC with a lot of damage resistances. though then i find they just target my barbarian who only has -2

oldlamehand

Not so easily. It take some time to get the equipment. Mages or sorcerers can get these spells before finishing any of the big quests. Of sourse, well equiped fighter is very usefull as tank. Anyway, I'm tanking with mages very often. Even in some high level combats, it is very effective to use mages as tank and protections removers. Fighters and rangers can easily do lot of demage with Greater Whirlwind Attack, when enemies are trying to kill well protected mages.

Gotural

Actually, Stoneskin and Mirror Image's utility increase with AC. If your Mage has a very bad AC, his protections will go down in a round or two when focused by some archers or by a Fighter who's using GWW.
On the other hand, if your Mage has a really good AC, his buffs will stay in place for all the fight and you won't need to spend spell slots / time to refresh them.

oldlamehand

Gotural said:

Actually, Stoneskin and Mirror Image's utility increase with AC. If your Mage has a very bad AC, his protections will go down in a round or two when focused by some archers or by a Fighter who's using GWW.
On the other hand, if your Mage has a really good AC, his buffs will stay in place for all the fight and you won't need to spend spell slots / time to refresh them.

Of course, but I think AC 0 or -2 without buffs (for mage)is sufficient to keep stoneskin for while :-)

Darkcloud

I had - 30 displayed on my swashbuckler in tob.

ifupauline

Seldar said:

I have -15 in Icewind Dale without any potions and/or buff. And he is unstoppable, except in HoW by some rare enemies...

But in BG series, even with this vey low AC, I get hit by a lot of enemies. They are more powerful than in IW, like Drows, Demons, extra-planar etc...

Maybe in ToB when dealing with giants, but usually past -15 with buff, you are pretty hard to kill.

Wowo

atcDave said:

Wakukee said:

decado said:

Wakukee said:

I was under the impression that AC maxed out at -10, but I just got a character down to -11. Is there a benefit to this? Thanks!

In PnP - yes. In video games you can go way lower.

So is there a chart somewhere to look at? Does 1 lower AC mean they need 1 better to hit you?

Its more a formula than a chart. Each "1" is about a 5% change. In PNP you roll a d20; and if you exceed your Thac0 minus the target's AC its a hit. So within the standard range of needing a 1 to 20 to its exactly a 5% increment for each modifier to hit or armor class. But at the extremes, you need to know a 20 always hits and a 1 always misses (5% chance of hit or miss regardless of AC or Thac0 extremes).

With regards to limits; core 2E rules set a limit on AC from -10 to 10. But this is widely ignored. Mathematically there's no reason for the limit. Especially since there is always the chance of a hit or a miss. So most DMs, like the IE games, allow for unlimited progression above and below on AC.

It's misleading to equate it to a 5% percentage. At AC 1 an enemy with 20 Thac0 needs a 19 or 20 to hit you. If you then find a ring of protection and your AC goes to 0 then those same enemies only hit you on a a 20 and - assuming you're wearing a helmet - are taking 50% less damage than before.

The realisation that a single point of AC can equate to 50% reduction in incoming damage is what makes very low AC so good and moderately low AC so bad.

In IWDee it's so easy to hit the threshold where any character is only taking 5% hits from most enemies with a few specific buffs:
Base AC 1 (full plate, Barkskin or spirit armor)+4 dex +2 bard song+2 protection item+2 prot evil 10ft+4 improved invis+2 defensive harmony+2 recitation= -17 AC

elminster

If you've gotten your AC to be so low that enemies are missing you 90% of the time another 5% isn't significant. Very few enemies have more than 2-3 attacks per round anyways so in all likelihood the character being attack wasn't likely to take much (if any) damage to begin with.

Jarrakul

Yeah, as Wowo points out, each point yields a 5 percentage point difference in the tally of which incoming attacks actually hit the character. This is highly distinct from a 5% difference in incoming damage. Essentially, each point of AC subtracts a set amount of average damage from enemy attacks, but multiplies the character's expected survival time. Thus, AC actually yields increasing returns as it goes lower. 1 point of AC is quite literally more powerful to a character who already has a -10 AC than to a character who only has a 5 AC.

This, for reference, is why many modern games have weird formulae for damage reduction or dodge chance that appear to produce diminishing returns. Typically, the appearance of diminishing returns is an illusion, and the actual result is constant returns (as opposed to the increasing returns of apparently-linear defense systems).

TheGreatKhan

I've had way below -20 AC in the past. I still recall getting hit quite a bit.

lunar

A high lvl swashbuckler can easily reach -22 or better ac. With use any item, he can don the heaviest armor, the most enchanted shield, and other nifty items that give ac bonuses. On top of his swashbuckler ac bonuses. (Something like up to +8 ac at lvl 40) he can also use scrolls or items to cast improved invisibility that is an effective +4 ac, or blur that is +3, also by means of greater evasion hla he can increase his ac even further.

Ac is like 'go hard or go home' in ToB, you really need something like the above example, an effective ac of -30 (with modifiers from blur, improved invisibility, and appropriate defensive girdle) will be very useful in ToB. Add potion of absorbtion and you can have an effective ac of -40 against crushing attacks:NOTHING that uses crushing weapons will hit that unless critical. Acs of -10 or around are not much different than an ac of 10 when you are against enemies that have modified Thac0s of -10 or better. If that's the best you can do, you might just as well go naked against the dragons and giants in ToB.

skinnydragon

Of course there is the built in cap that stops AC getting to good ie if an enemy needs a 20 to hit you no matte how much your AC improves they will still only need a 20 to hit you.

lunar

skinnydragon said:

Of course there is the built in cap that stops AC getting to good ie if an enemy needs a 20 to hit you no matte how much your AC improves they will still only need a 20 to hit you.

Or 19 will critical hit too if the enemy has single weapon or two hander style. Happens a lot in scs. Also critical hit or smite hlas will always hit.

Darkcloud

lunar said:

skinnydragon said:

Of course there is the built in cap that stops AC getting to good ie if an enemy needs a 20 to hit you no matte how much your AC improves they will still only need a 20 to hit you.

Or 19 will critical hit too if the enemy has single weapon or two hander style. Happens a lot in scs. Also critical hit or smite hlas will always hit.

So a 19 still will always hit if you crit with it?