Generating and using the Luck stat from S.P.E.C.I.A.L.

[Theodoxus]

I'm sure I'm late to the party when it comes to Fallout, the video game. I knew a bit (and played the original Wasteland as a kid, a LOT), but didn't really know about the stats system used until I started watching the series. I've always been a fan of anagrams and acronyms, and I was in shock when I learned what S.P.E.C.I.A.L. meant.

Now, since each attribute maps to a D&D attribute, either directly (Strength, Intelligence), or comparatively (Dexterity -> Agility, Wisdom -> Perception), it makes sense that they could be used for D&D... well, except for that elusive Luck stat.

So, I'm here to see if what I'm planning to do with it, would work, with folks around here being all brainy and whatnot.
*Note, I'm not using the Fallout version of base 5 with 5 points to spend, this is the standard 4d6dL of 5th Ed D&D)

If we map the 6 attribute modifiers for D&D to SPECIAL, you get:

Strength (Strength)
Perception (Wisdom)
Endurance (Constitution)
Charisma (Charisma)
Intelligence (Intelligence)
Agility (Dexterity)

What I'm thinking of doing is adding the attribute modifiers together, to generate a whole number that equals your Luck pool.

So, if your attributes and mods were:

S: 16 (+3)
P: 10 (+0)
E: 14 (+2)
C: 8 (-1)
I: 15 (+2)
A: 14 (+2)

Your Luck pool would be 3+0+2-1+2+2=8

So, what does a Luck pool do? It allows you to add up to your current pool amount, to any d20 roll you make. So, with 8 points, you might add 2 to an attack roll, reducing your pool to 6. You might then add 4 to a saving throw, leaving 2. Then add those two to a skill check later on.

Luck would then restore the full pool on a short rest.

I could see a couple additional options. Perhaps spend 5 Luck to make a roll with advantage (or burn 5 Luck to force an enemy to roll with disadvantage) akin to a Paladin Lay on Hands granting different forms of healing for 5 points. In this regard, I'd turn the Lucky feat into a bonus pool of 15 Luck points, which still allows for their use to create advantage, but also to tip a miss into a hit, or a failed save into a made one.

The only lingering question I have is how to determine when you can use the pool. I'm thinking after the roll is made and the result is known, so you can 'push Luck' into a success (or force a reroll for disadvantage just before an attack hits). This is obviously a bit more powerful than 'after the roll, but before the result', but that doesn't feel like luck, but a gamble. Closely related, but not the same. Also, even with a short rest recharge, the pool won't be so large that Luck can be used willy-nilly.

Thoughts?

[Notafish]

In the system you describe, I would also want to know how much "luck" I would need to spend to push a failure into a success. It doesn't feel quite as "lucky" to me as the rerolls from the Lucky feat (luck and gambling do go together as concepts for me), but I think I would have fun with the system.

In point buy, most characters would have close to the same amount of luck, right? Vanila PHB human could make out pretty well, though.

[clash]

I like the way it rewards classes that are naturally more MAD. Classes like monk and barbarian would end up with more luck because of pushing more stats higher for their class which is a good balancing factor. However, it creates a kinda odd paradox where classes like rogue that fit the luck theme better are more SAD and would likely have lower luck.

[HephaistosFnord]

I'm sure I'm late to the party when it comes to Fallout, the video game. I knew a bit (and played the original Wasteland as a kid, a LOT), but didn't really know about the stats system used until I started watching the series. I've always been a fan of anagrams and acronyms, and I was in shock when I learned what S.P.E.C.I.A.L. meant.

Now, since each attribute maps to a D&D attribute, either directly (Strength, Intelligence), or comparatively (Dexterity -> Agility, Wisdom -> Perception), it makes sense that they could be used for D&D... well, except for that elusive Luck stat.

So, I'm here to see if what I'm planning to do with it, would work, with folks around here being all brainy and whatnot.
*Note, I'm not using the Fallout version of base 5 with 5 points to spend, this is the standard 4d6dL of 5th Ed D&D)

If we map the 6 attribute modifiers for D&D to SPECIAL, you get:

Strength (Strength)
Perception (Wisdom)
Endurance (Constitution)
Charisma (Charisma)
Intelligence (Intelligence)
Agility (Dexterity)

What I'm thinking of doing is adding the attribute modifiers together, to generate a whole number that equals your Luck pool.

So, if your attributes and mods were:

S: 16 (+3)
P: 10 (+0)
E: 14 (+2)
C: 8 (-1)
I: 15 (+2)
A: 14 (+2)

Your Luck pool would be 3+0+2-1+2+2=8

So, what does a Luck pool do? It allows you to add up to your current pool amount, to any d20 roll you make. So, with 8 points, you might add 2 to an attack roll, reducing your pool to 6. You might then add 4 to a saving throw, leaving 2. Then add those two to a skill check later on.

Luck would then restore the full pool on a short rest.

I could see a couple additional options. Perhaps spend 5 Luck to make a roll with advantage (or burn 5 Luck to force an enemy to roll with disadvantage) akin to a Paladin Lay on Hands granting different forms of healing for 5 points. In this regard, I'd turn the Lucky feat into a bonus pool of 15 Luck points, which still allows for their use to create advantage, but also to tip a miss into a hit, or a failed save into a made one.

The only lingering question I have is how to determine when you can use the pool. I'm thinking after the roll is made and the result is known, so you can 'push Luck' into a success (or force a reroll for disadvantage just before an attack hits). This is obviously a bit more powerful than 'after the roll, but before the result', but that doesn't feel like luck, but a gamble. Closely related, but not the same. Also, even with a short rest recharge, the pool won't be so large that Luck can be used willy-nilly.

Thoughts?

Given modern sensibilities on balance, shouldn't Luck go the other way? i.e., the lower your other Abilities, the higher your Luck?

[Theodoxus]

Given modern sensibilities on balance, shouldn't Luck go the other way? i.e., the lower your other Abilities, the higher your Luck?

Possibly, though I'm not sure what the baseline Luck should be in that case.

I've done a pretty massive overhaul of the basic plan for attributes for the OSR I'm tinkering with.

Taking a beat from 2nd Editions Skills and Powers, I've split each attribute into two components:

Strength: Muscle and Stamina
Perception: Intuition and Willpower
Endurance: Health and Fitness
Charisma: Appearance and Leadership
Intelligence: Knowledge and Reason
Agility: Aim and Balance

Then, to generate your actual attributes, each sub-attribute gets 1 point in one or the other (so, you might have Muscle 1 and Stamina 0).
You then get 6 points to spread as desired (even bumping one sub-attribute by 6, if you'd like). You can also lower sub-attributes down to a minimum of -2, to gain more sub-attribute points.
Your race will provide 3 points as well.
Once the sub-attributes are finalized, add each sub-attribute pair together to obtain the attribute's modifier.
Luck is then the total of all your attributes, as described in my OP. So, outside of any feats, everyone starts with 15 Luck.

Then, I have Derived Stats from the attributes:
Accuracy (Strength + Perception)
Brawn (Strength + Agility)
Damage Resistance (Perception + Endurance)
Encumbrance (Endurance + Intelligence)
Glamour (Endurance + Charisma)
Health (Endurance + Agility)
Initiative (Perception + Agility)
Intimidation (Strength + Charisma)
Mental Resistance (Perception + Charisma)
Physical Resistance (Strength + Endurance)
Psicraft (Perception + Intelligence)
Speed (Strength + Intelligence)
Spellcraft (Charisma + Intelligence)
Strain Resistance (Charisma + Agility)

Skills are based on two sub-attributes, like Acrobatics is Fitness + Balance; Empathy is Intuition + Willpower.
There are 66 skills based on every paring, and proficiency is based on successful uses - you can even start learning new skills just by trying them. Leveling is based on skill proficiencies rather than experience points, so it's generally recommended taking at least one combat skill to help advance levels quickly.

[Yakk]

My stab at adding Luck to D&D (not fallout inspired) merged Str and Con into Brawn, then added Luck.

Luck added to HP (instead of Brawn) on even levels (and at level 1, as I had a level 0 d8 HD).

Luck was used for:
1: Death saves. 20+ means you get up with 1 HP. (I also have death-save for damage instead of auto-fail, which actually makes being down MORE lethal because as the DM I can aggressively not pull punches: everyone stabs a downed foe once unless they are running.)
2: Prof bonus times/long rest you could replace a roll (attack, save or check) with a luck save after you made it.
3: You could instead roll a Luck Save against an enemy roll (try to beat it) to make it fail.
4: Crit fails/successes on Luck Saves are extra big.
5: Fighters and Barbarians have Brawn/Luck saving throws (instead of Brawn/Brawn)
6: Rogues have Dex/Luck (instead of Dex/Int). Slippery Mind adds Wis and Int saving throws to Rogues.

This is less of a resource point system - the only thing you count are "prof times per long rest" - and more of an attribute.

[Maat Mons]

My inclination is to say that anything called "luck" shouldn't let you get a result higher than the maximum you would otherwise be able to obtain. Instead, it should just make it more likely that you'll get the highest result you'd otherwise be able to obtain.

[Riftwolf]

My inclination is to say that anything called "luck" shouldn't let you get a result higher than the maximum you would otherwise be able to obtain. Instead, it should just make it more likely that you'll get the highest result you'd otherwise be able to obtain.

Agreed. I also like a simple rule rather than a Luck pool. To that end:

Luck: You can give fate a nudge to turn a failure to success. When rolling any d20, add or subtract half your luck modifier (rounded up) to the roll, to a minimum of 1 and maximum of 20. Critical successes and failures are unaffected by this, and this modifier doesn't change a dice roll into a critical success or failure.

So if you have a score of 20 and modifier of +5, you add +3 to any roll below 18 and above 1 before other modifiers. In this instance, a roll of 17, 18, 19 and 20 are counted as 20, but only a roll of 20 is critical. A roll of 2 is counted as a 5, but 1 is still a critical failure.
Likewise, if you have a Luck of 8 and modifier of -1, you subtract -1 from all rolls. A 20 is still a critical success, but everything else is slightly worse.

This stops a lucky player being able to beat a proficient one most of the time, while an unlucky player is hindered but not unplayable or at the whim of a DM. It feels a little 3.5y to be adding extra numbers, but Lck 10-11 is an opt-out if you're wanting to simplify. I'm sure there's some point buy cheese (a Luck of 6 has the same penalty as 9) that'd need balancing, but this is the easiest rule for Luck I could come up with (aside from FNVs blanket skill bump and insane crit boost)

[Vogie]

What I'm thinking of doing is adding the attribute modifiers together, to generate a whole number that equals your Luck pool.

So, if your attributes and mods were:

S: 16 (+3)
P: 10 (+0)
E: 14 (+2)
C: 8 (-1)
I: 15 (+2)
A: 14 (+2)

Your Luck would be 3+0+2-1+2+2=8


I would try to make it a bit more straight forward. The way you interact with the luck stat is by rolling at or over the number without modifiers (called a "flat check" in Pathfinder 2e)

Luck is initially generated, as in the OP, by combining the other modifiers at first level. Luck itself, on the other hand, isn't a modifier - it's just the score. Your luck is not impacted by ASIs, as it fluctuates on its own. We'll get to that in a moment.

Luck can be used in a couple ways

Death Saves - it's the original luck check. You either pass or fail. Except, instead a flat 10, you roll your luck stat.
Beginners Luck - Doing any d20 check on anything you're not proficient, including skills, trying to cast a spell (such as with a scroll), use an item weapon or tool. Once you use luck on a skill or save in this manner, mark it on your character sheet with a star or dash - you can't use beginner's luck again until you level up.
Near Miss - When you would take damage from an attack or AOE, you can roll luck to either evade the attack or jump 10 ft in any direction, potentially removing yourself from the Area of Effect.
Stumble Upon - (This use is always Subject to GM fiat) You can roll luck outside of combat for the universe to act in your direction in a small subtle way. Successfully rolling Luck when falling, for example, might manifest as a bush or impeccably timed hay cart that arrests your fall; it might provide a small retcon concerning mundane relationships or items the PC has (Such as "Actually, I did buy a second healer's kit when we were back in town", "I went to school with one of the professors at this university", or "Oh, you mean this map? I made a copy of it before Nem E. Sis broke in and stole it")
Push your Luck - When making a check, save, or attack when you don't have inspiration, advantage or any other reroll option, you can do a flat roll against your Luck Score as a way to succeed. However, whenever you push your luck, the GM gains a metacurrency that they can then use to give a monster advantage on a roll, a refresh on their abilities, or as a Legendary Resistance charge (using 5e terms). If using in D&D 5e, This acts essentially the same as the Lucky feat with a downside - if the Lucky feat exists in the same system as the SPECIAL stats, then it just gives a small number of times you can Push Your Luck without that GM metacurrency downside. Your luck would still increase or decrease by using it.

Speaking of which, that would be how the thing would ultimately work:

Whenever you roll on your luck and succeed, your luck score increases. You can't have more than 20 luck
Whenever you roll luck and fail, the luck score decreases. You can't have less than 2 luck - a 1 on your luck roll will always fail.
So in our original example, the character starts with a low luck score - 8. If that PC starts using it, it'll slowly increase. They roll to dive away from a fireball and succeed (rolling an 8 or higher), they now have 9 Luck.

You'll guess correctly that, because the Luck score is a low number, each individual PC will be more likely to be 'lucky' when they're low level - This is just another version of the above-mentioned Beginner's Luck.