Luck: What it is and how it works
Alonso
Member Posts: 806
This article discusses luck in the games. Most of the information here has been provided by @semiticgod.
Each time a die is rolled and a luck modification applies, the modification is added or subtracted from the roll, but without exceeding the roll natural limits. What? You didn’t understand that? Don’t worry, neither did I the first 200 times. Let's see: The "natural limits" of a roll are its maximum and minimum values. For instance, the natural limits of a d20 roll are 1 and 20. A luck modification cannot make the roll go beyond these maximum and minimum values. An example might help:
Flint the warrior has a +2 luck bonus. He attacks twice with his long sword (1d6 damage). The first time he attacks he rolls a 15. Adding the luck bonus, his effective attack roll is 17 (hit). He rolls a 3 in his damage roll. The luck bonus means he actually inflicts 5 damage (we assume there aren’t other bonuses/penalties).
The second time he rolls a 19 in his attack roll. The luck bonus would make that a 21, but since 21 is outside the natural limits of a d20 roll (1-20), it actually makes it a 20 (hit). By the way, he does NOT get a critical hit (unless he already had a critical with 19, of course). Then he rolls a 6 in his damage roll. Again, the luck bonus would make that an 8, but since 8 is outside the natural limits of a d6 (1-6), the result stays at 6, i.e., he only inflicts 6 points of damage.
Now a 5th level mage casts a Fire Ball on our poor Flint (and he fails his save throw). That’s 5d6 points of damage. The rolls of those 5 dice are: 1, 2, 3, 4, 5. Without his luck bonus, Flint would take 1+2+3+4+5 = 15 points of damage. However, the luck bonus reduces the damage he takes. The 5 becomes a 3, the 4 becomes a 2, the 3 becomes a 1. But again, the luck effect cannot modify a roll beyond its natural limits (1-6 in this case), so the the 2 just becomes a 1 and the 1 remains unchanged. The result is that he takes 1+1+1+2+3 = 8 points of damage.
The following picture illustrates the difference between the maximum delay (Jaheira, to the left) and no delay at all (Minsc, to the right):
- After a long adventure, a priest and a blade get fatigued. They get a -1 penalty to luck.
- The priest casts Chant. Chant gives them +1 bonus to luck. This is the luck effect 1, which stacks with the luck effect 2 from being tired. The combined effect is that their luck becomes neutral (1-1=0).
- The blade casts Luck on himself. Both the Chant spell and the Luck spell create the luck effect 1, which doesn't stack with itself, so he doesn't get a luck bonus.
- The blade starts to sing. He and the priest get a +1 bonus to luck because the blade song (+1 to luck) creates the luck effect 2, which stacks with the luck effect 1 from Chant.
Note: Originally this post was a set of questions about luck. I include the original post in the spoiler for reference:
What is luck?
Luck is a game stat, like strength or AC. It affects the performance of all the creatures in combat and also when performing some other actions. Luck can be positive (+1, +2, etc.), negative (-1, -2, etc.), or neutral (0). Positive luck means better performance, negative luck means worse performance. Neutral luck has no effect.The confusion
Over the years there has been a lot of confusion about how luck works in the Infinity engine games. The concept of luck is never explained in the games or their manuals, and most of the information they provide about luck is either wrong or misleading. Apart from that there are several inconsistencies in the mechanics of the games:- Luck is the name of a stat, but it’s also the name of two effects. An effect is a change in a game stat. The two luck effects change the value of the luck stat, but they do it in different ways. One luck effect stacks and the other doesn’t. The luck effect obtained from the Luck spell, Chant, and the Lucky Scimitar in IWD does not stack. However, the luck obtained from other sources does.
- Luck is also the name of a spell. Casting the Luck spell creates a luck effect in the target (the effect that doesn't stack). This effect improves the luck stat of the target. However, the Luck spell also gives several other bonuses (to saving throws and thieving skills) which are unrelated to the luck stat.
- In the Icewind Dale series luck works a bit differently than in the Baldur's Gate series.
How does it work?
Luck affects many aspects of the game:- Attack rolls.
- Physical damage dealt.
- Magical damage taken. In this context magical damage means any damage except the base damage of a weapon. That includes damage from spells, wands, abilities, weapon elemental damage, etc.
- Reaction times.
- Thief skills.
- Effectiveness of the spell Mirror image.
Attack and damage rolls
The luck of a character is added to each of his attack rolls and physical damage rolls, and subtracted from each magical damage roll when he is attacked. But remember, this is AD&D, it’s always more complicated. Just adding a bonus to your roll would be too “simple”. And who wants something simple when you can have exactly the same thing, but twice as complicated? Well, you, me, the rest of the world… but not the AD&D creators, for sure. So this is the whole story:Each time a die is rolled and a luck modification applies, the modification is added or subtracted from the roll, but without exceeding the roll natural limits. What? You didn’t understand that? Don’t worry, neither did I the first 200 times. Let's see: The "natural limits" of a roll are its maximum and minimum values. For instance, the natural limits of a d20 roll are 1 and 20. A luck modification cannot make the roll go beyond these maximum and minimum values. An example might help:
Flint the warrior has a +2 luck bonus. He attacks twice with his long sword (1d6 damage). The first time he attacks he rolls a 15. Adding the luck bonus, his effective attack roll is 17 (hit). He rolls a 3 in his damage roll. The luck bonus means he actually inflicts 5 damage (we assume there aren’t other bonuses/penalties).
The second time he rolls a 19 in his attack roll. The luck bonus would make that a 21, but since 21 is outside the natural limits of a d20 roll (1-20), it actually makes it a 20 (hit). By the way, he does NOT get a critical hit (unless he already had a critical with 19, of course). Then he rolls a 6 in his damage roll. Again, the luck bonus would make that an 8, but since 8 is outside the natural limits of a d6 (1-6), the result stays at 6, i.e., he only inflicts 6 points of damage.
Now a 5th level mage casts a Fire Ball on our poor Flint (and he fails his save throw). That’s 5d6 points of damage. The rolls of those 5 dice are: 1, 2, 3, 4, 5. Without his luck bonus, Flint would take 1+2+3+4+5 = 15 points of damage. However, the luck bonus reduces the damage he takes. The 5 becomes a 3, the 4 becomes a 2, the 3 becomes a 1. But again, the luck effect cannot modify a roll beyond its natural limits (1-6 in this case), so the the 2 just becomes a 1 and the 1 remains unchanged. The result is that he takes 1+1+1+2+3 = 8 points of damage.
Reaction times
When you give a character the command to attack an enemy, it takes him some time to react and start to move. This delay is variable, it ranges between 0 and 0.5 seconds. Positive luck increases the chance of having a short delay (or no delay at all). Negative luck increases the chance of having a long delay.The following picture illustrates the difference between the maximum delay (Jaheira, to the left) and no delay at all (Minsc, to the right):
Thieving skills
Luck affects the chances of success when setting, finding and disarming traps, opening locks, stealth. It doesn't affect the chances of success when detecting illusions and picking pockets. For the abilities affected, each point of positive luck roughly increases the chances of success by 1% (negative luck has the opposite effect). You can read a more detailed and accurate description here.Mirror image
When a mage protected by the spell Mirror image is attacked, his attacker can either hit the mage or one of the images. The chances of each outcome depend on the luck of the mage. The higher his luck, the higher the chances that his attacker hits one of the images, and vice versa.IWD series (IWD and IWD2)
Apart from the mechanics explained above, in the IWD series luck also affects critical hit and critical miss chances (so in our previous example our warrior does make a critical when he rolls 19). That's especially useful because hammers, halberds, spears, arrows, and axes deal triple damage rather than double damage on critical hits.How do you get lucky (or unlucky)?
This is a list of the sources of luck (positive or negative) in all the games (except Planescape:Torment, I don't have information about that one). Some of these sources only affect luck itself, others create other effects as well.All games
- Fatigue: -1 luck when the character becomes fatigued. An extra -1 for every extra four hours without resting.
- Intoxication: Penalty to luck and bonus to morale. The penalty goes from -2 to -12 and the bonus from +2 to +12, both depending on the amount of drink taken and the constitution of the character. The negative effects of the penalty always outweigh the benefits of the bonus. Slow Poison and Heal cure it.
All games bar IWD2 (i.e.: BG1, BG2, SoD and IWD)
- Luck spell: +1 luck, +1 to saves, +5% thief skills.
- Chant: +1 luck, +1 to saves, +1 to healing rolls (Staff of Curing, Mass Cure spell, etc.)
BG series: BG, BG2 and SoD
- Bard Song (unkitted): +1 luck at level 1, +2 at level 15, +3 at level 20.
- Blade song: +1 luck (doesn't scale with level).
Baldur's Gate
- Rabbit's Foot (Alora): +2 luck, +2 AC, +10% thief skills.
Baldur's Gate II
- Wish spell: Two of its effects affect luck:
- One intoxicates enemies, giving them a -12 luck penalty for 200 rounds. It bypasses magic resistance and offers no saving throw. It is dispellable and can be blocked by Spell Immunity: Enchantment and possibly Minor Globe of Invulnerability, as it is a level 3 Enchantment spell. Slow Poison and Heal cure it.
- The other effect gives -5 luck for 60 seconds party-wide.
- One intoxicates enemies, giving them a -12 luck penalty for 200 rounds. It bypasses magic resistance and offers no saving throw. It is dispellable and can be blocked by Spell Immunity: Enchantment and possibly Minor Globe of Invulnerability, as it is a level 3 Enchantment spell. Slow Poison and Heal cure it.
IWD series: IWD and IWD2
- Chaos of battle (Priest of Tempus ability): 10% chance of a luck bonus between +1 and +5, depending on level.
Icewind Dale
- Lucky Scimitar: +1 luck.
- Tymora's Melody: +1 luck, +3 to saving throws, +5% thief skills.
Icewind Dale 2
- Luck spell: +1 luck.
- Tymora's Melody: +1 luck, +3 to saving throws, +2 to thief skills, Alchemy, and Knowledge (Arcana).
- Tymora's Loop (extremely rare random drop): +3 luck.
- Young Ned's Knucky: +2 to Luck, +2 to saving throws.
- Breaking the mirror in the Ice Temple: -20 luck.
- Chant: Unknown.
Stacking luck effects
As stated above, there are two luck effects, one which stacks and one which doesn’t.- Luck effect 1: Obtained from the Luck spell, Chant, and the Lucky Scimitar in IWD. It does not stack with itself, but it does stack with luck effect 2.
- Luck effect 2: Obtained from other sources. It stacks with itself and with luck effect 1, with one exception: bard songs. Bard songs don't stack with themselves, although they do stack with different songs. For example, two jester songs don't stack, but a jester song and a blade song do.
- After a long adventure, a priest and a blade get fatigued. They get a -1 penalty to luck.
- The priest casts Chant. Chant gives them +1 bonus to luck. This is the luck effect 1, which stacks with the luck effect 2 from being tired. The combined effect is that their luck becomes neutral (1-1=0).
- The blade casts Luck on himself. Both the Chant spell and the Luck spell create the luck effect 1, which doesn't stack with itself, so he doesn't get a luck bonus.
- The blade starts to sing. He and the priest get a +1 bonus to luck because the blade song (+1 to luck) creates the luck effect 2, which stacks with the luck effect 1 from Chant.
Note: Originally this post was a set of questions about luck. I include the original post in the spoiler for reference:
I’m trying to understand the concept of luck in the game, but most of the information I’ve found is confusing or contradictory. I’ve compiled information from the manuals and the forums trying to clarify it:
What do you think?
Manuals
Survival Guide:- While the [bard] song is playing, the party’s morale and luck are higher.
- A character can continue to operate at peak efficiency for 24 hours in game-time (2 hours realtime). After that, the characters will start to complain and their attributes begin to suffer. For every four hours beyond this 24-hour mark, the player will receive a –1 luck penalty (–1 to all rolls).
- Intoxicated characters gain a morale bonus, but receive a luck penalty.
- Luck spell: The recipient of this spell is lucky in everything they do for the next 3 rounds, receiving a 5% bonus to any actions. This includes Saving Throws, to-hit rolls, thieving skills, etc.
- Fatigued characters suffer a –1 penalty to luck; every four hours after becoming fatigued, this penalty increases by one. […] Luck affects every d20 roll your character makes.
- THAC0 and Armor Class: The d20 roll can also be modified by circumstances such as spells, special abilities, and luck.
- Luck spell: This spell’s recipient is lucky in everything they do for 3 rounds. They receive a +1 bonus to all actions, including Saving Throws, to-hit rolls, thieving skills, and anything else requiring a d20 roll. Contradictory: Thieving skills don't use d20 rolls.
- Stuff that affects luck:
- Bard song: Unspecified bonus.
- Intoxication: Unspecified penalty.
- Fatigue: -1 penalty for every four hours fatigued.
- Luck spell: 5% bonus to all actions (?). Alternatively, +1 bonus to all actions.
- Bard song: Unspecified bonus.
- Effects of luck:
- -1 to all rolls for each -1 penalty.
- Affects Saving Throws, to-hit rolls, thieving skills, etc.
- Affects d20 rolls.
- -1 to all rolls for each -1 penalty.
Forum
These are summaries of the most interesting posts I've read. They're not quotes, so I hope I got them right:- @lunar: Luck adjusts damage rolls. When casting offensive spells which involve dice rolling your luck bonus is added to each die roll, up to the maximum die roll result.
- @JuliusBorisov: A luck bonus reduces the damage taken from magic and elemental damage by one point per die, down to a minimum of 1.
- @Semiticgod: There are two different effects called luck, and they work in more or less different ways.
- @Ark_Tolei: Luck doesn’t affect damage (dealt or taken).
Conclusion
My completely uneducated guess is that the key to understanding this is this post by semiticgod. If I get that right (and I probably don’t) the source of the confusion is the fact that the word “luck” is used in the game to describe two different effects rather than one. These two effects work similarly in some aspects and differently in others, hence the contradictions and the confusion.What do you think?
Post edited by Alonso on
26
Comments
I'm failing to see the contradiction.
Add in single weapon style and that katana from dragons eye and 20% of all hits are criticals!
When rolling a d20, add 5% (+1).
I'm not trying to troll you, I really can't understand what the problem is despite your text. Maybe it's some language barrier that I'm unable to get through.
"For every point of Luck, the character receives a +1 bonus to the minimum damage caused by his weapons (up to the normal maximum damage of the weapons) and a +1 bonus to hit. Furthermore, each point of Luck also reduces the damage from offensive spells by 1 dice roll (i.e. a character with 1 Luck would receive 10d5 damage from a Fireball instead of 10d6). Multiple Luck bonuses are cumulative and stack with each other. These bonuses are not visible on the character record screen but they do show up in the combat log."
One
There are two kinds of luck, opcode 22 and opcode 133. The ONLY difference between them is that 22 stacks, and 133 does not. The Luck spell (and the Lucky Scimitar in IWD) both use opcode 133 and do not stack; all other sources of luck use opcode 22, and stack.
Two
The Chant opcode works just like opcode 133. It has the same effects and does not stack with itself.
Three
Luck behaves differently in IWD2 and the other IE games.
In BG1, BG2, and SOD, luck DOES affect:
1. To-hit rolls
2. Spell damage taken
3. Physical damage dealt
Luck does NOT affect:
1. Critical hit and critical miss chances (unconfirmed)
2. Physical damage taken
3. Spell damage dealt
4. Saving throws
5. Thieving skills
So a lucky warrior will hit more often, deal more damage with weapons, and take less damage from spells. But he or she will NOT be more likely to survive a Disintegrate spell. A lucky mage will NOT deal more damage with his or her spells, though they will still take less damage from enemy spells. A lucky thief isn't better at stealing or hiding.
In IWD2, luck DOES affect:
1. To-hit rolls
2. Spell damage taken
3. Physical damage dealt
4. Critical hit and critical miss chances (confirmed, like the others)
Luck does NOT affect:
1. Physical damage taken
2. Spell damage dealt
3. Saving throws
4. Thieving skills
So a lucky character gets all the bonuses that a BG character gets from luck, plus an increase in critical hit chances. That's especially useful because (1) nothing is immune to critical hits in IWD2, and (2) hammers, halberds, spears, arrows, and axes all deal triple damage rather than double damage on critical hits.
Four
Outside of IWD2, the level 2 Luck spell does more than just impact luck. The Luck spell also improves saving throws and thieving skills--not because luck impacts those things, but because the Luck spell has a few extra opcodes. Other sources of luck do not always improve saving throws or thieving skills, because they don't have the extra opcodes.
The luck opcode does not impact saves or skills, but certain sources of luck do.
Other sources of luck include:
Bard Song (+1 luck at level 1, +2 at level 15, +3 at level 20)
Tymora's Melody (+1 luck, +3 to saving throws, +5% skill bonuses, IWD only)
Tymora's Melody (+1 luck, +3 to saving throws, +2 skill bonuses, IWD2 only)
Tymora's Loop (+3 luck, extremely rare IWD2 drop)
Rabbit's Foot (+2 luck, +2 AC, +10% skill bonuses, Alora only)
Rabbit's Foot (+1 luck, modded IWD2 only)
Fatigue (negative luck)
Bad Luck (Wish effect)
Chant technically isn't luck, but it has the exact same effects.
+5% and +1 on a d20 roll are technically the same--1 out of 20 is the same as 5 out of 100. But that's misleading, because thieving skills--which, unlike other rolls, are represented by percentiles--do not all actually work as percentiles. First, there are extra situational modifiers to stealth and pickpocket chances that don't show up in your Record screen. Second, lockpicking and detecting and disarming traps are more like thresholds than percentiles: your skill needs to be this high to pick this lock, and the higher it is, the fewer tries it will take.
So, whatever. Both are accurate when it comes to hit rolls, but both are misleading when it comes to thief skills.
Fatigue incurs bad luck, right? When fatigued my characters miss a lot more and when a spell hits them they take more damage than I expect them to. Is this the luck effect?
Does luck affect your HP rolls when leveling up?
I don't know if you are right, and what is reported in the character record screen reports something wrongly, without the increment being really implemented, or if you are wrong about this point.
It seems to me quite complicated, if someone wants to play the game and not use near infinity and deal with opcodes, spell mechanics and similar stuff.
Maybe we can work out together a list for each game that shows the possible sources of luck and indicate also what it does, avoiding technicalities like the opcode does not do it but also an other opcode is applied so the effect is present, and with what it stacks.
Something that can help who doesn't like to look in the engine mechanics, but wants to use the spells/items that in the in game description state that they increase luck in an informed way. then maybe the OP can edit the opening post and add those list.
Baldur's Gate:
Fatigue: -1 luck for every point of fatigue above 6
Chant: effectively, +1 luck and +1 to saves, does not stack
Bard Song (unkitted): +1 luck at level 1, +2 at level 15, +3 at level 20
Luck spell: +1 luck, +1 saves, +5% thief skills, does not stack
Rabbit's Foot (Alora): +2 luck, +2 AC, +10% thief skills
Siege of Dragonspear:
Fatigue: -1 luck for every point of fatigue above 6
Chant: effectively, +1 luck and +1 to saves, does not stack
Bard Song (unkitted): +1 luck at level 1, +2 at level 15, +3 at level 20
Luck spell: +1 luck, +1 saves, +5% thief skills, does not stack
Baldur's Gate 2:
Fatigue: -1 luck for every point of fatigue above 6
Chant: effectively, +1 luck and +1 to saves, does not stack
Bard Song (unkitted): +1 luck at level 1, +2 at level 15, +3 at level 20
Luck spell: +1 luck, +1 saves, +5% thief skills, does not stack
Bad Luck (Wish effect): -5 luck for 60 seconds, party-wide
Icewind Dale:
Fatigue: -1 luck for every point of fatigue above 6
Chant: effectively, +1 luck and +1 to saves, does not stack
Luck spell: +1 luck, +1 saves, +5% thief skills, doesn't stack with the Lucky Scimitar
Lucky Scimitar: +1 luck, doesn't stack with Luck spell
Tymora's Melody: +1 luck, +3 to saving throws, +5% thief skills
Icewind Dale 2:
Fatigue: -1 luck for every point of fatigue above 6
Luck spell (IWD2): +1 luck, does not stack
Tymora's Melody: +1 luck, +3 to saving throws, +2 to thief skills, Alchemy, and Knowledge (Arcana)
Tymora's Loop: +3 luck (extremely rare random drop)
Rabbit's Foot (modded game only): +1 luck
Breaking the mirror in the Ice Temple: -20 luck
Chant: untested. Possibly +1 luck, but since it also disables spellcasting for 10 rounds and slows movement rate to half, it might not be worth using most of the time.
Can you please edit your list and add also what stacks with itself and the others? Ie in BG2 if luck spell (+1) compensate a -1 from fatigue or is possible to have +5 luck staking lev20 bard song, chant and luck spell?
Then it would be perfect. EDIT thanks, now is perfect.
I am gonna put this topic in my bookmarks.
But the tread is helping me a lot to understand how much it helps and when it helps.
Because is easy to overrate or underrate something that you don't know.
Now I know that if I want to help my thief to steal or hide the luck spell is useful but there is no point to have a bard singing or waste a chant spell for it. and knowing if I can get a massive +5 bonus, maybe in order to backstab some nasty enemy, staking the song of a lev 20 bard and the 2 spells or if is not useful because they don't stack is also important to know when is worth to try to increase luck instead of having the party members doing something more useful in that moment.
And the fact that in BG2 only the luck spell improves saving throws is a very important thing to know when you are trying to survive some encounters where you know that the party members or charname risk a pietrification or an istant killing spell.
If your list is correct (specifically 2 in the first list and 2 and 4 in the second) then the description in the manuals is incorrect (and the description in the game even more so).
Apart from that, what is an opcode?
An opcode is an effect. They determine how almost everything in the Infinity Engine works. Damage, AC, portrait icons, movement rate, and vorpal strikes are all separate opcodes. There are about 300-450 different opcodes depending on the game, and each opcode works differently depending on the parameters. Immunities are often opcode-specific.
Two examples to illustrate:
Free Action uses opcode 101 to grant immunity to a bunch of different opcodes, all of which affect movement. However, depending on your version of the game, it may not grant immunity to opcode 45, the stun opcode. The reason why (Rings of) Free Action don't always block stun is because certain versions of the game don't block that specific opcode.
Or, take the Ring of Gaxx. It uses one opcode to improve your AC, five different opcodes to improve each of your saves, another opcode to apply regeneration, another opcode to improve your magic resistance, two copies of the same opcode (with different parameters) to grant immunity to poison and disease, another opcode to grant 100% poison damage resistance,* then two copies of yet another opcode to give you portrait icons showing you have magic resistance and regeneration, then four copies of another opcode to prevent the dialog box from saying you got poisoned or diseased (there are four different strings it has to prevent), and finally three copies of another opcode to prevent three different portrait icons relating to disease and poison. That's 21 different opcodes to apply all the benefits that the ring is supposed to grant.
*This is necessary because some sources of poison (like that of the Flail of Ages +5) use opcode 12, the damage opcode, to deal poison damage, rather than using opcode 25 to deal poison damage over time (like from a spider bite).
There are lots of different examples like that. Having immunity to one opcode doesn't mean you're immune to a similar one, and it's often necessary to use multiple opcodes to produce just one concrete effect. Differing opcodes is also why you sometimes see enemies get that white orb over their head even when your Hold Monster spell doesn't paralyze them: the orb and the paralysis use different opcodes, and the target might be immune to only one of them.
You are right. You're not rolling d5, you're rolling d6 and then substracting.
Luck is
possiblythe most powerful effect in BG. A character with 2 points of Luck can reduce Magic Missile damage by 40%. It also beefs up thieves' backstab substantially since it affect your minimal damage, pretty much keeping you safe from those 1-point damage rolls.Note: The difference between the description of Chant in the game and in the manual is that the game says that it also affects magical damage (both dealt and taken).
In BG1, BG2, and SOD, luck DOES affect:
2. Spell damage taken
Luck does NOT affect:
3. Spell damage dealt
and also:
Chant works like luck, but it also improves all saving throws by 1.
So I would say only magical damage dealt, and magical damage is a very improper term that should be not used in manuals and descriptions as is easy to confuse it with magic damage (the one of MM and ADHW), spell damage is the correct definition.
If the enemy isn't in range when Chant is cast, or if they resist the effect using magic resistance or MGOI, they will not receive any penalties. If Chant does hit them, though, they will take more damage from your spells.
Anyway, since you mention it... What's the difference between the spell damage you deal and the spell damage the enemy takes? They sound like the same thing to me (in this context).
Also, if someone enters the fight after the chant spell has been cast, they will not take increased damage from your spells where as they would if the chant spell buffed your characters.
Other stuff like that.