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kamikasei
2013-08-21, 05:06 PM
I'm trying to make a list of different ways to roll dice in RPGs. My motive is to write a dice bot; I want to cover a wide range of game types with as few commands as possible, while ideally having the bot do as much of the work as it can in terms of interpreting and summarizing results.

There's "roll one or more dice and look at the total". This would cover d20, d100 games like Call of Cthulhu or Eclipse Phase, and no doubt plenty of others. These are pretty straightforward: all you care about is the total, or perhaps for some purposes the individual rolls that make up the total too.

There are "count successes" games like WoD or Exalted where you roll a pool of dice and then count the ones that come up higher than a certain value. These can be a little hairy, since the threshold can change, and there are special cases such as tens counting double.

There are "roll and keep" systems like L5R, where you roll a pool of dice and keep a subset of them. This is just the first type with added combinatorics, unless there are extra mechanics I'm not familiar with (very likely).

There are "count matching sets" systems like Legends of the Wulin, where you roll a dice pool and then combine matching dice. In LotW this means two 8s become 28, a single 3 becomes 13, etc. There may be similar systems which handle this a little differently.

Then there are weirder systems like Fate (results of +, 0, or - per dice) or a Babylon 5 RPG I remember hearing about that was d6-d6 or something like that, but these are sufficiently unusual to leave to the user rather than the bot (and/or can easily be converted to different systems, like Fate becoming 4d3-8).

I'm looking for:
a) suggestions as to other systems I haven't thought of, and wrinkles on how the above are used;
b) information on what games use which systems.

Thanks in advance!

The Rose Dragon
2013-08-21, 06:27 PM
This link (http://www.giantitp.com/forums/showthread.php?t=293453) may be somewhat relevant.

Rondodu
2013-08-21, 06:34 PM
What do you plan to do? A dice roller which lets players figure out if they succeeded and possibly by which margin?

In any case: In Nomine Satanis/Magna Veritas (there is an american variant called In Nomine) use a “d666”, which is three different d6 used in a peculiar way. In its 4th edition (previous editions may differ), you take the first two dice and combine them as you would two d10 to make a d100 (but in base 6 with figures from 1 to 6 instead of from 0 to 5). You check this result on a table for success. The last die (plus bonuses) is used to see how much you succeed/fail. In any case, 666/111 is awesome/catastrophic/unpredictable according to the team you play in.

So this would be a “display several dice results in predetermined order” (do *not* sort them) or “roll a dice and display result in a custom base with custom figures”*if you really wish to.

In Continuum (I’ve play it once, so I might misremember), you roll a single d10 againt your skill + bonuses/maluses. If you roll 0, 1 or your exact skill (no bonuses/maluses), roll a second one. If you get the same result on the second die, you respectively get: a critical failure, a huge success or some help from a fellow time traveller.

So this could be “roll d100” or “roll d10 and flip a coin (10% chance of winning the toss)”.

I know there are games out there which use card drawing as random generators, but I can’t think of any right now.

kyoryu
2013-08-21, 06:42 PM
(and/or can easily be converted to different systems, like Fate becoming 4d3-8).

Fate really *is* 4d3-8. It's just that the -2 is applied to each die.

It's a pretty traditional dice mechanic, actually, as it really traces its roots back to GURPS' 3d6.

kamikasei
2013-08-21, 06:43 PM
What do you plan to do? A dice roller which lets players figure out if they succeeded and possibly by which margin?
Pretty much. If you want to roll 1d20+4, for example, it'll just tell you the roll and the total, and it'll be up to you to determine if that's a success or failure. For Exalted, though, it could tell you the number of successes, doubling tens. For LotW, it could make the sets for you and give you the resulting numbers you have to work with. For L5R, it could automatically select and sum the best N results (if I'm understanding how that system works correctly).

The reason I'm asking about a lot of systems is so I can extract the basic commands and options for them that will do the most to take mindless arithmetic off the players' hands without the thing becoming overly bloated. To that end, thanks for the responses so far! Please include details where possible of points like whether individual dice and their ordering are important, too.

Grey Watcher
2013-08-21, 06:59 PM
Slightly off-topic, but I have a sneaking suspicion this site may be of some help somehow:

http://anydice.com/

erikun
2013-08-21, 07:06 PM
For most systems I'm familiar with, displaying the dice and the total should work out just fine. If I ask for 10d6 and it gives me the results and the total, then it doesn't matter if I'm playing with a dice pool (Burning Wheel) or totaling them all up (Fireball in D&D). I have all the numbers handy. Just a note that some games want to know the results on the dice anyways, even with adding them up; Eclipse Phase gives a "critical" based on doubles on the d% roll, seperate from if the roll succeeded or failed.

Fate dice are quite literally +1, 0, -1 or the 1d3-2 as Kyoryu mentioned. You'd probably want a specific command to indicate Fate dice; *dF is what Fate/Fudge uses.

Exploding dice are a bit of a problem, as if they're turned off by default then games with exploding dice need to put in a special command, and if they're turned on by default then you'll need a special command to not use them. I suppose you could set it up to respond differently based on the game being used, although most people could probably just re-roll if needed. Note that with some games, it depends which dice exploded off which dice, so just adding extras to the dice pool isn't necessarily that good of an idea.

CombatOwl
2013-08-23, 12:03 PM
I'm trying to make a list of different ways to roll dice in RPGs. My motive is to write a dice bot; I want to cover a wide range of game types with as few commands as possible, while ideally having the bot do as much of the work as it can in terms of interpreting and summarizing results.

There's "roll one or more dice and look at the total". This would cover d20, d100 games like Call of Cthulhu or Eclipse Phase, and no doubt plenty of others. These are pretty straightforward: all you care about is the total, or perhaps for some purposes the individual rolls that make up the total too.

There are "count successes" games like WoD or Exalted where you roll a pool of dice and then count the ones that come up higher than a certain value. These can be a little hairy, since the threshold can change, and there are special cases such as tens counting double.

There are "roll and keep" systems like L5R, where you roll a pool of dice and keep a subset of them. This is just the first type with added combinatorics, unless there are extra mechanics I'm not familiar with (very likely).

There are "count matching sets" systems like Legends of the Wulin, where you roll a dice pool and then combine matching dice. In LotW this means two 8s become 28, a single 3 becomes 13, etc. There may be similar systems which handle this a little differently.

Then there are weirder systems like Fate (results of +, 0, or - per dice) or a Babylon 5 RPG I remember hearing about that was d6-d6 or something like that, but these are sufficiently unusual to leave to the user rather than the bot (and/or can easily be converted to different systems, like Fate becoming 4d3-8).

I'm looking for:
a) suggestions as to other systems I haven't thought of, and wrinkles on how the above are used;
b) information on what games use which systems.

Thanks in advance!

Some other approaches:

Roll-And-Pluck: You roll a pool of, say, five dice at the start of a fight. You prioritize your actions in a round by placing the higher dice on the things you find more important. "I roll a 4, a 2, a 3, a 1, and a 6. I want to put my 6 on my initiative, the 4 on my swords, the three on my defense, the two on my movement, and the one on my perception." Add the die's score to your character's ability ratings to determine success/failure. I used that on a custom game I made. It would probably work better with cards though.

Inverse Dice: Rather than trying to add up to succeed, assume success is automatic unless the target can prevent it by assigning failures from a pool. For example, everyone gets 5d10 to roll at the start of a turn. 9s and higher count as a "failure" that can be applied against another character's action. Again, I don't know anyone else to use this approach for anything. Really only suited for narrative games with superpowers and such--or really grim horror games (where "failures" should be granted on 10s only).

Yahtzee: Surprised no one mentioned this, but you could just use a poker-like priority for certain combinations of dice.

Non-Transitive: This is a general category of dice system where some dice roll higher than others in the same category; for example, you might have a system where there are three kinds of dice--blue, green, and red. Blue dice might roll only 1s, 2s, and 4s, while Green dice roll 2s, 3s, 4s and 5s, and Red dice roll only 3s, 5s, and 6s. Presumably characters with better skills would express that by rolling better dice. Alternately, this would include systems where tests are always made against a fixed difficulty but some tests are made with larger die than others.

Dice Divination: Rather than having numbers, use symbols with different meanings (a sword means a success, a broken arrow means a complication, etc). The results of an action are divined by looking at the symbols you roll with the pool you construct. An example of this is Warhammer Fantasy or Edge of the Empire. Ultimately these sorts of systems can be expressed mathematically, but the actual play style differs enough that it is best to treat it separately.

kamikasei
2013-08-23, 12:17 PM
Some other approaches:
Thanks for the input, but I'm not looking to design a system, just to make a tool that's useful for systems that already exist. If a mechanic either isn't already in use somewhere or is too obscure for anyone to think of an example, I'm not concerned about including it.

(Incidentally, your "roll-and-pluck" idea sounds like how Legends of the Wulin works, except that for most purposes there you need two or more matching dice in order to base an action off them. For example, a standard starting character's would roll 7d10 for initiative, getting (say) 8 7 7 3 2 1 2, meaning they can assign the 27 to their initiative, use the 22 for a Tactics check to analyze their opponent's style, and use the 18 for a special bonus because they're fighting unarmed.)

CarpeGuitarrem
2013-08-23, 12:24 PM
There's some games with little wrinkles and variations on these approaches.

For instance, The One Ring is a roll-and-add with a d12 and d6s, but Weary characters don't count dice that roll 1-3, every 6 gives you a degree of success, and the d12 is actually a d10 plus an Eye of Sauron (counts as 0, and triggers negative effects, so you have to note when it happens) and a Gandalf Rune (grants success, though some feats still require degrees of success).

Fate is mathematically replaceable with d6-d6; it's a strict bell curve.

The One Roll Engine (including its spinoff Hollowpoint) looks at what dice match, and organizes them into "sets" which incorporate into a back-and-forth; one dice roll can fuel multiple actions. It may be outside of your scope.

Warhammer Fantasy 3e and Star Wars: Edge of the Empire use a unique dice system. There's different types of dice to represent your raw ability, your ability from skill, negative circumstances, positive circumstances, and difficulty of the situation/active opposition. Each die has a custom spread of a few symbols, and then you sum the symbols up to produce a result with multiple aspects. Also might be so far out as to land outside your scope.

huttj509
2013-08-23, 01:12 PM
Mistborn adventure game: Roll Xd6 (between 2 and 10). Result is your highest doubles, ignoring sixes. Sixes are "nudges" which can be used to modify the result narratively (tripping an opponent, for example).

Example: Rolling 6 dice, 1 1 5 6 6 6 would be a result of "1 and 3 nudges."
5 5 5 5 5 6 would be "5 and 1 nudge"
6 6 6 6 6 6 would be "0 and 6 nudges" Probably not do anything, but I'm not sure if nudges can have effect on a failure.

IronFist
2013-08-25, 03:43 AM
Tenra Bansho Zero uses a dice pool mechanic with a twist.
You roll a number of dice depending on the attribute, but the target number depends on the skill.

Rakaydos
2013-08-25, 11:26 AM
The Citadale System (Ironclaw/Nogglestones/Myriad Song) uses a Dice Pool where a moderately skilled person might be rolling 1d12, 2d8, and a d4 vs 4, and rerolling a single roll of 1.

LibraryOgre
2013-08-25, 01:04 PM
Hackmaster uses a die style called "Penetrating", noted as d20p, d4p, etc. When you roll the maximum on a penetrating die, you roll again... but subtract 1 from whatever comes up.

So, for example, a shortsword does 2d6p. Last night, our thief rolled a 6, followed by a 6, followed by a 5. This gives a total of 15... 6 + (6-1) + (5-1).. and that was just on the first d6p.

Arbane
2013-08-25, 02:51 PM
There's also 'roll and take highest' - Silhouette and Savage World use variations on this. With Savage Worlds, it's usually 1dX, but 'wild card' characters (PCs and some important villains) get to roll an extra 1d6 and take the higher.

Silhouette rolls (skill level, usually 1-5)d6, takes the highest, and adds 1 for each additional 6, if any. (If skill is 0, roll 2d6, take the LOWER one.)


I know there are games out there which use card drawing as random generators, but I can’t think of any right now.

TORG has its Drama Deck, which influences what can be done in a fight. Deadlands uses poker hands for spellcasting. Castle Falkenstein uses cards instead of dice. Everway uses a Tarot-like deck instead of dice, and Marvel Saga uses a 5-suit deck as a randomizer.

Over The Edge's Weather The Cuckoo Likes supplement has a rules variant that uses words cut out of a newspaper and drawn from a hat as a randomizer, but that's probably a _bit_ outside the scope of this project.

Felhammer
2013-08-25, 03:28 PM
Marvel Heroic Roleplaying was all about opposed rolls between the Player and either an enemy or the Doom Pool (a pool of dice used as a stand in for things that do not have stat blocks).

Let's say that a O*N*E Sentinel is trying to smash Wolverine with his boot. To do this, he would roll:

Solo: d6
Doing My Duty: d8
Superhuman Strength: d10
Superhuman Durability: d10
Combat Expert: d8

Let's say he rolled a 24 with an effect die of d10.

In response, Wolverine thrusts his claws up above his head, grits his teeth and hopes for the best. In that case he would roll:

Solo: d10
I'm The Best There is At What I Do: d8
Godlike Stamina: d12
Adamantine Claws: d10
Combat Master: d10

Wolverine rolls really poorly with a 5, 3, 2, 3, 2. So he takes four of his dice to make total of 13, saving his d12 for his effect die.

Since Wolverine's Effect Die is larger than the sentinel's, the latter's die is downgraded to a d8. So, in the end, Wolverine takes d8 Physical Stress from the stomp.


This system kind of falls under your "roll one or more dice and look at the total" mechanic but since every roll is opposed, I think it deserves a separate category. :smallsmile:

tzar1990
2013-08-26, 12:16 AM
I have a homebrew system in the works that's a strange sort of success-count system

The basic idea is that you roll 2d8, and compare each seperate die to a target number determined by your skill and various circumstance modifiers. Doubles under your skill was a critical success, two dice under your skill was a great success, one under was success, both over was failure, and doubles over was a critical failure.

It produced a system with more granularity than simple pass/fail, had a good probability curve as skill increased, and made it possible for the unskilled to beat their superiors without it being very likely at all, which I figured was more realistic.

CarpeGuitarrem
2013-08-26, 12:33 PM
Marvel Heroic Roleplaying was all about opposed rolls between the Player and either an enemy or the Doom Pool (a pool of dice used as a stand in for things that do not have stat blocks).

Let's say that a O*N*E Sentinel is trying to smash Wolverine with his boot. To do this, he would roll:

Solo: d6
Doing My Duty: d8
Superhuman Strength: d10
Superhuman Durability: d10
Combat Expert: d8

Let's say he rolled a 24 with an effect die of d10.

In response, Wolverine thrusts his claws up above his head, grits his teeth and hopes for the best. In that case he would roll:

Solo: d10
I'm The Best There is At What I Do: d8
Godlike Stamina: d12
Adamantine Claws: d10
Combat Master: d10

Wolverine rolls really poorly with a 5, 3, 2, 3, 2. So he takes four of his dice to make total of 13, saving his d12 for his effect die.

Since Wolverine's Effect Die is larger than the sentinel's, the latter's die is downgraded to a d8. So, in the end, Wolverine takes d8 Physical Stress from the stomp.


This system kind of falls under your "roll one or more dice and look at the total" mechanic but since every roll is opposed, I think it deserves a separate category. :smallsmile:
This is Roll and Keep with dice of different sizes. The Effect Die does add its own wrinkle, however.

Dogs in the Vineyard is another outlier where you roll a pool of different dice, and then spend two at a time in a back-and-forth with the other player. So you wind up using all (or most) of the dice that got rolled.

Rondodu
2013-08-27, 08:06 AM
I seem to remember that Feng Shui is 1d6-1d6+skill against difficulty. Can’t remember is the dice are explosive, though.

Arbane
2013-08-27, 11:37 AM
I seem to remember that Feng Shui is 1d6-1d6+skill against difficulty. Can’t remember is the dice are explosive, though.

They are - on sixes, reroll and add. (or subtract, if it's the negative die.)