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What is with Armour Class being a negative number? (And general questions)

FranpaFranpa Member Posts: 637
Edit: I don't mean to antagonize or generate hostility between me and anyone else, I don't mean to upset fanatics of the original game system. I'm a novice and am just curious why the game still, to this day sticks to this weird seemingly confusing system.

I assume this is the reason for it (Correct me if I'm wrong):

When something buffs Armour Class it lists it as a positive buff prefixed by a + symbol, even though it lowers your armour class and if something debuffs your Armour Class then it is prefixed with a - symbol even though it raises your Armour Class.

Now, I believe it works this way because stats on items are de/buffing the dice you roll to determine if an attack hits, misses or crits and Armour Class is a representation of the difference between you and Armour Class 0? (This explanation of mine doesn't make sense, if someone wants to elaborate on it/rectify it that would be nice)

I dunno, I'm sure there's some kind of BOARD GAME reason behind how it is currently set up, but from a computer game perspective I can't see how it adds any value to the experience other then making things needlessly confusing. Can't the positive/negative status of Armour Class be reversed so that positive values on gear is good and have a positive effect on AC? That way the positive/negative values on gear make SENSE and it afaik has zero impact on the gameplay unless you're playing with a Board and real dice.

Also, save throws and stuff, are positive numbers good for them? Or negative? Seems odd to have one system where positive numbers are good and the underlying system is easy to understand and another system where positive numbers are good, but they have a confusing negative impact on a stat.
Post edited by Franpa on
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Comments

  • FranpaFranpa Member Posts: 637
    edited November 2013
    TJ_Hooker said:

    Lower numbers are better for THAC0, saving throws, and AC. I believe the convention in-game is that bonuses are listed as positive numbers, even though they actually lower AC, THAC0, etc. As for why this is, well... I remember hearing that it had something to do with holding over legacy aspects of the game from earlier editions of D&D. Basically you're better off not spending too much time wondering why.

    It just, it makes it really hard to get engrossed when the underlying systems are so.... not straight forward.

    Edit: It doesn't help that each line of stats is prefixed with a Dash, so you end up with --5 or -+5 for the first stat on each line...
    TJ_Hooker said:

    Franpa said:

    Can't the positive/negative status of Armour Class be reversed so that positive values on gear is good and have a positive effect on AC? That way the positive/negative values on gear make SENSE and it afaik has zero impact on the gameplay unless you're playing with a Board and real dice.

    Yup, it's called 3rd edition.
    Doesn't Baldur's Gate 2 make use of a rule set more suited for a computer game?
  • TJ_HookerTJ_Hooker Member Posts: 2,438
    edited November 2013
    Franpa said:

    TJ_Hooker said:

    Lower numbers are better for THAC0, saving throws, and AC. I believe the convention in-game is that bonuses are listed as positive numbers, even though they actually lower AC, THAC0, etc. As for why this is, well... I remember hearing that it had something to do with holding over legacy aspects of the game from earlier editions of D&D. Basically you're better off not spending too much time wondering why.

    It just, it makes it really hard to get engrossed when the underlying systems are so.... not straight forward.
    Oh, don't get me wrong, I completely agree that the rules are counter-intuitive, and overall more complicated than they need to be. But the rules in BG are here to stay, so there isn't really anything you can do but try and get used to them. And really, after you get the hang of it, it's not too bad.
    Franpa said:

    TJ_Hooker said:

    Franpa said:

    Can't the positive/negative status of Armour Class be reversed so that positive values on gear is good and have a positive effect on AC? That way the positive/negative values on gear make SENSE and it afaik has zero impact on the gameplay unless you're playing with a Board and real dice.

    Yup, it's called 3rd edition.
    Doesn't Baldur's Gate 2 make use of a rule set more suited for a computer game?
    Well, Baldur's Gate does take many liberties with the rules, but things like THAC0 and AC are pretty fundamental to 2nd edition AD&D (the ruleset used in BG1 and 2).
  • CutlassJackCutlassJack Member Posts: 493
    In the original D&D rules, AC went as low as Zero. But eventually they realized they needed to have more numbers when they made the Advanced rules. Hence the reason for Negative ACs. It was tacked onto the existing system, which was descending. The tabletop version used complex tables on the GM's wall sized screen to keep track of everything.

    In 3rd Edition they wisely scrapped they system in favor of an Ascending AC system. But Baldur's Gate was created in the 2.5 rules, so its why we have to deal with it. Thankfully since its a computer game, we don't need to deal with all the charts personally.
  • AstroBryGuyAstroBryGuy Member Posts: 3,437
    Franpa said:

    Edit: I don't mean to antagonize or generate hostility between me and anyone else, I don't mean to upset fanatics of the original game system. I'm a novice and am just curious why the game still, to this day sticks to this weird seemingly confusing system.

    When Baldur's Gate was written, the current version of the D&D game was Advanced Dungeons and Dragons, 2nd Edition. So, they adapted the rules of AD&D to the Baldur's Gate. Baldur's Gate 2 was released in 2000, the same year as Dungeon & Dragons, 3rd Edition. Considering that BG2 was a sequel, changing the underlying game version mid-stream would have been difficult (not to mention the game coders would have been using playtest rules for 3E, since they were in development at the same time).

    At this point, updating the rule system in BGEE/BG2EE to 3E/3.5E/4E/Next would require a complete re-write of the game content to insure proper balance and party progression.
    Franpa said:

    I assume this is the reason for it (Correct me if I'm wrong):

    When something buffs Armour Class it lists it as a positive buff prefixed by a + symbol, even though it lowers your armour class and if something debuffs your Armour Class then it is prefixed with a - symbol even though it raises your Armour Class.

    Now, I believe it works this way because stats on items are de/buffing the dice you roll to determine if an attack hits, misses or crits and Armour Class is a representation of the difference between you and Armour Class 0? (This explanation of mine doesn't make sense, if someone wants to elaborate on it/rectify it that would be nice)

    Basically, THAC0 − AC = roll needed to hit. "+" is used for bonuses, even though a bonus to armor class lowers it. Probably something psychological about people not understanding or liking a "negative bonus".
    Franpa said:


    I dunno, I'm sure there's some kind of BOARD GAME reason behind how it is currently set up, but from a computer game perspective I can't see how it adds any value to the experience other then making things needlessly confusing. Can't the positive/negative status of Armour Class be reversed so that positive values on gear is good and have a positive effect on AC? That way the positive/negative values on gear make SENSE and it afaik has zero impact on the gameplay unless you're playing with a Board and real dice.

    Dave Arneson (co-creator of Dungeons & Dragons) adapted an Armor Class system he'd developed for an naval combat game called Ironclads to Dungeons & Dragons. Ironclads also had a descending AC system, so, D&D inherited from there.

    As to why they implemented the AC system for BG, its simple: They were creating a game based on AD&D; so, they used AD&D rules. The D&D/AD&D descending AC system was also so ingrained at the time that many CRPGs also implemented similar armor systems (e.g. The Bard's Tale, Wizardry). Even if Baldur's Gate hadn't been an official AD&D game, it still could likely have used descending AC in 1998.
  • atcDaveatcDave Member Posts: 2,392
    The math of it is simple enough. Attacker's Thaco minus target's AC is what you need to roll on a d20 to hit.

    The problem is occasional poorly written item and spell descriptions. Especially adapting stuff over from PNP. Something could conceivably be a plus or minus to a die roll, or a plus or minus to an armor class, with opposite results. Many descriptions are inconsistent or unclear in their terminology. The player just needs to be aware of if something is a good or bad effect. Its not that hard to figure out from there.
    A very common such error is anything that gives you a plus to hit, shows up as lowering your Thaco. Well in PNP it makes perfect sense to add your plusses to your die rolls. But on the computer it can look a little awkward to see the Thaco going down instead.

    I love 2E and I wouldn't want to see any other system in use. But I do agree a lot of descriptions were not as clear as they could have been.
  • meowzormeowzor Member Posts: 37
    PhD in mathematics....
    ...
    ...
    ...
    Still cant decipher THAC0
  • ElendarElendar Member Posts: 831
    meowzor said:

    PhD in mathematics....
    ...
    ...
    ...
    Still cant decipher THAC0

    To Hit Armor Class 0. There you go. :P
  • atcDaveatcDave Member Posts: 2,392
    meowzor said:

    PhD in mathematics....
    ...
    ...
    ...
    Still cant decipher THAC0

    I don't think I would admit that. (BS in Business Management and a certified Control Tower Operator; and it makes perfect sense to me).
  • SceptenarSceptenar Member Posts: 606
    atcDave said:

    meowzor said:

    PhD in mathematics....
    ...
    ...
    ...
    Still cant decipher THAC0

    I don't think I would admit that. (BS in Business Management and a certified Control Tower Operator; and it makes perfect sense to me).
    Bachelor of Mechanical Engineering, Master of Systems Engineering, and I find it quite simple. I think someone is either joking or overhyping their credentials a bit, I certainly expect a Ph.D to be better at math than me.
  • atcDaveatcDave Member Posts: 2,392
    Sceptenar said:

    atcDave said:

    meowzor said:

    PhD in mathematics....
    ...
    ...
    ...
    Still cant decipher THAC0

    I don't think I would admit that. (BS in Business Management and a certified Control Tower Operator; and it makes perfect sense to me).
    Bachelor of Mechanical Engineering, Master of Systems Engineering, and I find it quite simple. I think someone is either joking or overhyping their credentials a bit, I certainly expect a Ph.D to be better at math than me.
    Oh I don't know. One of the regulars in my gaming group had a PhD in Math; and he used to get so angry when we gave him the bill at a restaurant; "I don't use actual numbers anymore guys!". Too funny.
  • CoM_SolaufeinCoM_Solaufein Member Posts: 2,606
    Negative THAC0 means you're a god amongst mere mortals.
  • marcerormarceror Member Posts: 577
    Simply put BG uses 2nd edition D&D, and this is how such things were calculated in this version. 3rd edition happily went to positive numbers representing improvements and eliminated THAC0.
  • SceptenarSceptenar Member Posts: 606
    atcDave said:


    Oh I don't know. One of the regulars in my gaming group had a PhD in Math; and he used to get so angry when we gave him the bill at a restaurant; "I don't use actual numbers anymore guys!". Too funny.

    Well, imaginary numbers is a real thing... ;)

    http://en.wikipedia.org/wiki/Imaginary_number
  • FinneousPJFinneousPJ Member Posts: 6,455
    Nice choice of words there, @Sceptenar :D
  • EudaemoniumEudaemonium Member Posts: 3,199
    marceror said:

    Simply put BG uses 2nd edition D&D, and this is how such things were calculated in this version. 3rd edition happily went to positive numbers representing improvements and eliminated THAC0.

    Its actually funny. Since I've only ever played BG and other 2E-derived games like Torment and IWD, my brain can't actually imagine how that would be possible.
  • elminsterelminster Member, Developer Posts: 16,317
    Seems like a lot of work to change it all at this point.
  • atcDaveatcDave Member Posts: 2,392

    marceror said:

    Simply put BG uses 2nd edition D&D, and this is how such things were calculated in this version. 3rd edition happily went to positive numbers representing improvements and eliminated THAC0.

    Its actually funny. Since I've only ever played BG and other 2E-derived games like Torment and IWD, my brain can't actually imagine how that would be possible.
    I've played every version in PNP and computer. And it just makes no difference at all which way the numbers run, it is all the same to me.
    In my own PNP game I run 2E for a variety of reasons; but which way armor classes run is a non-issue.
  • marcerormarceror Member Posts: 577
    edited November 2013

    marceror said:

    Simply put BG uses 2nd edition D&D, and this is how such things were calculated in this version. 3rd edition happily went to positive numbers representing improvements and eliminated THAC0.

    Its actually funny. Since I've only ever played BG and other 2E-derived games like Torment and IWD, my brain can't actually imagine how that would be possible.
    If you were ever exposed to 3ED + you would adust very quickly, as the later approach is so much more logical.

    All characters start with a base armor class (AC) of 10, plus any modifiers applied for high dexterity, armor, etc. To attack a character you roll a D20 (just as you did in 2ND edition), and add your base attack bonus (BAB), plus any modifiers for high attributes, magical weapons etc. If your total roll (die value + attack bonus) meets or exceeds the opponent's armor class, you strike with your weapon. If it's less, you miss.

    Like 2ED, a natural die roll of 1 always misses. A natural die roll of 20 always hits, and might result in a critical hit (you have to roll a second time, and if the second roll hits, it's a critical).

  • FranpaFranpa Member Posts: 637
    edited November 2013
    elminster said:

    Seems like a lot of work to change it all at this point.

    You could change the visual representation of buffs/debuffs in item descriptions by swapping the + and - symbols around. The fundamental behaviour doesn't change, however buff and debuff stats on items now behave logically in relation to other parts of the interface making the overall system significantly easier to comprehend (Positive buffs are now shown as a negative and indeed lower your stats since the actual behaviour behind the stat is unchanged, debuff stats are now shown as positive buffs and indeed raise your stats since the actual behaviour behind the stat hasn't changed).

    I assume that's easy to accomplish if you're familiar with editing the game files, however I'm unsure if you'd need to edit every single items description individually to accomplish it which would make the task pretty tedious.

    If I'm wrong about all this then please explain what I've missed/assumed wrongly.
  • ajwzajwz Member Posts: 4,122
    What is with character stats all being positive numbers?
  • FranpaFranpa Member Posts: 637
    edited November 2013
    ajwz said:

    What is with character stats all being positive numbers?

    I meant only for THAC0 and AC buffs/debuffs and maaybe Saving Throws, I'm not 100% sure if positive Saving Throws reduce your Saving Throws on your stat sheet like how THAC0 currently works.

    Edit: I may have misinterpreted what you said.
    Post edited by Franpa on
  • ajwzajwz Member Posts: 4,122
    I was being facetious :p
  • MortiannaMortianna Member Posts: 1,356
    atcDave said:

    The math of it is simple enough. Attacker's Thaco minus target's AC is what you need to roll on a d20 to hit.

    I've found that newcomers to 1e/2e rules are often confused by having to subtract a negative number from a negative number. For example, if a target has a -8 AC and its attacker has a -1 THAC0, then the attacker would need to roll a 7 or higher to hit (-1 minus -8 = 7). 3rd edition has the same concept with adding a negative modifier to one's "to hit" roll, so it's really not that different.
    atcDave said:

    I love 2E and I wouldn't want to see any other system in use.

    I feel the same way. I think it's a generational thing. The people who first encountered D&D in the 3rd+ editions seem to regard the 1e/2e system as unnecessarily arcane and antiquated. Those of us who started playing during 1e or 2e don't really see what the big fuss is all about.
  • GemHoundGemHound Member Posts: 801
    edited November 2013
    @Franpa It is actually really simple.
    THAC0 = To Hit Armor Class 0. this is the value you need to hit someone. You subtract the victims' AC from your THAC0 to see how easily you hit the victim.

    For example: No AC bonuses:
    THAC0 = 19, Enemy AC = 10; that means you have to roll higher than a 9 to hit the victim.
    Same with negatives.
    AC -6:
    THAC0 = 10. Enemy AC = -6; that means you need to roll higher than a 16 to hit the victim.

    Weapons that have +'s in front of them subtract from your THAC0 as well.

    So, same situation as before with a +2 longsword.
    THAC0 = 10, Enemy AC = -6; You need to roll higher than a 14 now to hit the victim.

    This is before going into proficiency points.
  • FranpaFranpa Member Posts: 637
    edited November 2013
    Mortianna said:

    atcDave said:

    The math of it is simple enough. Attacker's Thaco minus target's AC is what you need to roll on a d20 to hit.

    I've found that newcomers to 1e/2e rules are often confused by having to subtract a negative number from a negative number. For example, if a target has a -8 AC and its attacker has a -1 THAC0, then the attacker would need to roll a 7 or higher to hit (-1 minus -8 = 7). 3rd edition has the same concept with adding a negative modifier to one's "to hit" roll, so it's really not that different.
    For me the problem is literally having to interpret positive nunbers as negatives. Having +4 to Armour Class shouldn't take 4 away from Armour Class dammit! That's not how maths works!

    Edit: And thanks for the clarifications of how THCA0 works, it's appreciated. I do find this a little hard to comprehend but not impossible, just takes a bit of effort to wrap my head around it whenever I return to the game.
  • GemHoundGemHound Member Posts: 801
    edited November 2013
    Franpa said:

    Mortianna said:

    atcDave said:

    The math of it is simple enough. Attacker's Thaco minus target's AC is what you need to roll on a d20 to hit.

    I've found that newcomers to 1e/2e rules are often confused by having to subtract a negative number from a negative number. For example, if a target has a -8 AC and its attacker has a -1 THAC0, then the attacker would need to roll a 7 or higher to hit (-1 minus -8 = 7). 3rd edition has the same concept with adding a negative modifier to one's "to hit" roll, so it's really not that different.
    For me the problem is literally having to interpret positive nunbers as negatives. Having +4 to Armour Class shouldn't take 4 away from Armour Class dammit! That's not how maths works!
    @Franpa
    It is exactly "how maths works!".
    Low armor class, and low THAC0 are good things. what I do not like about the newer editions is how at the end of the game you have around 70 AC, and THAC0 is non-existent. I prefer the smaller numbers.
  • FranpaFranpa Member Posts: 637
    edited November 2013
    GemHound said:

    @Franpa
    It is exactly "how maths works!".
    Low armor class, and low THAC0 are good things. what I do not like about the newer editions is how at the end of the game you have around 70 AC, and THAC0 is non-existent. I prefer the smaller numbers.

    What I mean is that if you have an Armour Class of -8 and you get a Ring of +4 Armour Class, the maths would logically be -8 + 4 which equals -4, yet in this game it equals -12. That is what annoys me, it makes comparing gear stats with each other somewhat of a chore. The THAC0 stuff isn't as bad as this/is easier for me to comprehend on a regular basis (Is there anywhere in the game that tells you the AC of the enemy you're fighting?).
  • GemHoundGemHound Member Posts: 801
    @Franpa Not really without Shadowkeeper, EEKeeper, or Gatekeeper.

    THAC0 and AC work the same and yield smaller numbers to work with than 3rd or 4th edition.
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