Dice Mechanic Primer

[LizardLips]

I've been tinkering with rules and homebrewed games for years now, but I think I really want to buckle down and turn one of my nebulous ideas into a real playable game. I'm nearly certain it'll never get published but it'll be mine, and I think that's cool.

I've been poring over the info scattered across the Forge, but the one thing that I need to get up to speed on is mechanics. I'm familiar with half a dozen games, but I was hoping that there was some sort of catalogue of mechanics (various dice, card, bidding, anything...) and perhaps a review of what kind of results they generate from other existing games. I don't want to bang my head against a wall to invent something new if its done before.

Also, is there some sort of program to generate probability statistics for different numbers and sides of dice which can accept "weirdness" (exploding dice, multiples adding together etc.)?

[Andrea Gualano]

... I was hoping that there was some sort of catalogue of mechanics (various dice, card, bidding, anything...) and perhaps a review of what kind of results they generate from other existing games.

A good starting point may be this article by John Kim, that includes an analysis of a few dice systems from commercial games and links to various software tools.

[Mike Holmes]

We have links to threads with formulae, but nothing like what you describe precisely (John's article is about as close as you'll get, I think).

OTOH, if you tell us something about your game, perhaps we can help you come up with an appropriate mechanic. Or at least narrow down the search some.

Mike

[Jeph]

I shall now present Jeff's Partial List of Dice Mechanics.

Rollover, Simple: This is the typical mechanic found in D20, CODA, Feng Shui, and other systems. It is characterised by rolling a fixed number of dice to generate a value, adding another value based on the character to the result, and comparing that total to a target. It can be either single die (d20), multiple die (CODA), or have little twists like Feng Shui's d6 minus  d6 set up.

Rollover, Dice Pool: This is the mechanic used in WEG d6 Classic and, to an extend, Legend of the Five Rings and 7th Sea. The character rolls a variable number of dice based upon some facet of the character, totals them up, and compares to a target. Sometimes you may also add a flat number to the total ("pips" in WEG d6). Another twist is to only count some of your dice, popularized by l5r's "roll and keep" system. Thus, if you have r6k4 and rolled 5, 6, 7, 8, 8, 9, you'd only keep the four highest--the 7, the two 8s, and the 9.

Rollunder: Used in GURPS and BRP and its derivatives (Pendragon, Unknown Armies, Hero Wars). Sort of like roll over simple, but backwards: you roll the dice, and succeed if you score equal to or under a value determined by your character. Circumstances can alter the die roll or max value.

Matching: Used in Sorcerer, *Claw, and SilCORE. Each side rolls a dice pool, and him scoring the single highest value wins. Discard ties until you have a victor. Alternatively, there is SilCORE's variant, in which you roll your dice pool and take the single highest die, then add +1 to that value for each die after the first that rolled its max. Thus, if you rolled 1, 3, 5, 5, your value would be 5; if you rolled 1, 4, 5, 6, 6, 6, your value would be 8. Iron/Jadeclaw introduces an interesting twist, in which the number of sides on the dice rolled varries more than the actual number of dice.

Matching, Anal Retentive: Sort of like Matching, and used in the board game RISK. In this case, each side rolls a pool, and you compare every single die of yours to one of your enemy's, highest to lowest. Him that comes out on top in the most matches is the victor. Thus, if I roll 10, 9, 9, 3, 1; and you rolle 8, 8, 8, 5, 4; I win 3 matches (10 on 8, 9 on 8, 9 on 8) and you win 2 (3 on 5, 1 on 4); thus, I am the overall victor.

Success Counting, fixed TN: Used in the streamlined Storyteller games (Exalted, Aeon trilgoy), Shadowrun, and d02: Know No Limit. Roll a dice pool, counting every die that comes up equal to or over (sometimes under) a fixed value as a success (7 or higher in the case of Exalted, the side you call for d02, etc). Compare successes scored to an enemy's total or a number of successes required. Many systems have an "exploding dice" mechanic, or some method of scoring more successes than dice rolled. A nice twist might be to make the size of the dice rolled variable.

Success Counting, Variable TN: Used in The Riddle of Steel and classic Storyteller games. This is exactly like the other Success Counting method, but the target number can change. For instance, in Riddle of Steel it can be determined by your Vocation rating or a weapon used; in the White Wolf games it is determined by circumstantial difficulty.

Duplicity: Used in my own game Pagoda (see .sig) and I'm sure a few others, but none commercial that I know of. Anyway, you roll a dice pool, and look for matches. The number of matches (I got three doubles) or extent of the match (I got a quadruples) or any combination thereoff (I got a triples and two doubles) might be what's looked for to determine success.

Note that there are literally hundreds of thousands or more possible ways to do things, including combinations of any of the above and things not even represented in this post in the slightest. Hell, Lxander has a mechanic based upon a roulette wheel. But those are the most common methods that I've seen.

Hope this is of some help,
--Jeff

[dyjoots]

Matching, Anal Retentive

Do you have an example of a role-playing game that has this as it's mechanic?  I'm quite fond of the way it works.


-- Chris

[ander75it]

Actually a system very similar by the one described by you is used in Godlike. You can download a pdf from their website if interested.
Bye,
Andrea

[Daniel Solis]

Actually a system very similar by the one described by you is used in Godlike. You can download a pdf from their website if interested.
Bye,
Andrea

Yup. The gist of it is that you roll a bunch of dice and count how many matches you have. From that single roll, you determine the "height" (Highest ranking matched dice) and "width" (number of matches), which, in turn, determine various aspects of task resolution. There are also some twists with the use of "wiggle dice," but you can read all about it in the PDF.

I'm curious, are there games that use the following system?

(stat)d(skill)
A character has, say, five base stats. Each of those stats governs a single type of die from d4 to d12. The ranking of skills determine how many dice are rolled when using that skill. So, if I want to swing a sledgehammer and knock over a pillar, I use my "strength" stat (which is a d8) and my "sledgehammerin'" skill (rank 4) to determine that I have a 4d8 dice pool for that action.

[Lxndr]

I thought Deadlands did something like that.

I know it's been done.  Ironclaw, maybe?

[Valamir]

No thats very Deadlands.

Iron Claw uses a pretty interesting system which is a pool of dice where each die is a different type based on where it came from.  You might make a skill roll by rolling 1d8 for an attribute, 1d6 for a skill level, 1d10 because of a special ability for your race, and 1d8 for a magic enchantment.  You roll them all together but I can't recall now whether its the sum of the dice or a per die target number that you're looking for.

[Jeph]

No thats very Deadlands.

Iron Claw uses a pretty interesting system which is a pool of dice where each die is a different type based on where it came from.  You might make a skill roll by rolling 1d8 for an attribute, 1d6 for a skill level, 1d10 because of a special ability for your race, and 1d8 for a magic enchantment.  You roll them all together but I can't recall now whether its the sum of the dice or a per die target number that you're looking for.

You take the highest single value and compare to a TN. Also note that dice explode when they roll max values, which, along with a bit of wonkiness, allows a character with any rating to beat any TN.

But it's kinda odd that you're more likely to succeed at TN 6 with a d4 rating than a d6 rating...

[Mike Holmes]

Immortal had something similar, IIRC.

Also, the system originally presented by Matt Snyder for Dreamspires was supposed to work this way.

Lots of games use just d(skill). Orx, the Window, etc.

Mike