Wednesday, July 13, 2011

Bread and Butter and Dice

Dice systems are, at their heart, kind of dull. This is probably a good thing, since most of the difference between systems can be built upon their framework, so you want them to be simple, reliable and dull. This is on my mind for reasons that are probably a different post, but I've been chewing on a core dice mechanic.

Right off the bat you have three big camps of dice mechanic. You have the flat roll, the tally, and the count. Flat roll is most famous in the various incarnations of D&D, which has used it as both roll vs. moving target (old D&D THAC0 tables) or roll + bonus vs target (4e). The "flat" roll may actually have a curve (as in the case of Dragon Age's 3d6) but it's always the same dice, and differentiations in skill are represented by changing the target number or changing the bonus. Fudge dice are another weird example of a flat roll that don't necessarily look it because the range is wacky (-4 to 4) but it's a fixed set of dice all the same.

Tally systems, such as those used in WEG's Star Wars or AEG's Roll & Keep system, are based on totaling up a variable number of dice. Variations in skill can change the size of the die pool, and while there may be some extra mechanical fiddliness in terms of how many dice are counted (as in the Case with Cortex+ or any game with bonus dice) , the core idea is that the pool of dice is the variable and as a subsidiary idea, the size of the dice may also be a variable.

Count systems are usually considered success counting systems, like Storytelling or Burning Wheel. You roll some pool of dice (of variable size, like a tally), but rather than add up the dice, you count the number of results that hit some particular criteria (such as 7+ on a d10, or 4+ on a d6). Left purely in that form, this is just a highly specialized tally system (effectively the dice have some number of 0's and some number of 1's) but it's worth differentiation from the tally because the ways it establishes differentiation can include changing the rules of success counting. For example, successes might usually be on a 7+, but in this particular area in which you excel, they might happen on a 6+. Thus, while the size of the die pool may be one axis, another will often include the means of determining successes.

There's a lot more fiddly in this. You can add bonuses to a Tally system to make it feel a little more flat-like. In any system, you can add variations in how you measure success and how you handle things like critical successes and failures (all to say nothing of rich rolling). You can get into wacky hybrids or edge cases (like set building), but those three models really cover the bulk of approaches, and they have different strengths and weaknesses.

Flat rolls are the simplest. Even when they require some math, it is usually quite simple, and perhaps more importantly it's _perceived_ as simple. Reading the die results in a flat roll is easy, with almost no learning curve. Even if the "post-processing" of adding bonuses or the like takes soem effort, it is -after- the roll, a critical point of distinction.

Tally rolls are probably the most robust. If you want to hang a million different mechanics off a roll, or make the die rolling a bit of a game in its own right (like rolling lots of dice, then doing many mini-resolutions from the pool) then this is probably the approach to take, but it absolutely runs the risk of daunting players. Even if you don't do a lot of fiddly stuff, the perception is that math is hard and slow, and tallying up the dice creates that sense of friction. This can be mitigated with small or familiar dice pools, but it's always the specter over the system.

Counts are something of a compromise. They offer much of the same mechanical robustness of Tallies, but they promise greater simplicity than doing math, and in my mind they deliver on that, at least to an extent. There can be a little bit more of a curve in picking up a count game, but the act of reading the dice is an educational one, and most people get much faster at it with only a little practice. Unfortunately, there are some problems that come with that. First, that simplicity is based on the method of counting remaining the same, and if the system leans on changes to that, it slows things down. Also, you can only rely on the simplicity scaling so far - if the dice pools get huge (like, Exalted huge) then it will still bog down.

All three methods can work very well. Even more, all three are robust enough that if there's some particular element you want to accentuate or avoid then you can easily tweak them to that end.

I'm dwelling on this because I have a dice system in mind for a project, and i want to step back and consider its weaknesses and strengths before I totally buy into it. More on that tomorrow.


  1. In Ironclaw, Chronica Feudalis or Savage Worlds, you roll a 'variable die type' dice pool and take the best roll. There may be any number of variables/factors, but the outcome is within a specific manageable range, that's imposed by the stronger factor. What is this mechanic's category?

  2. Tally. Pool size (measure in # of dice or die size) is still the yardstick for measuring skill, even if it's just a tally of the single best roll. Additional modifiers are elaboration on the theme.

  3. For my own game, I am using a tally system close to what Panos described. I went with it because it helps give consistency for highly skilled characters, while not robbing weaker characters of their chance of being very successful at the same thing.

    On the down side however, it makes a sense of scale a bit harder to find at times, as a person with a skill of one is just as capable of pulling off that masterwork roll; they just won't do it as often. Considering the feel of the world though, I felt it was appropriate.

  4. I find this post fascinating, cuz I (like everyone else) have played around with making a game. But every time it seems like I think I have a good mechanic, I find out someone already did that. :) Setting, and writing are things I can do. Gameplay mechanics are very hard, sometimes.

  5. Whilst waiting for a long compile once I started going through my RPG collection and extracting all the resolution systems, along with the various variations of them).

    It was interesting to not only see the different types of resolution system (which definitely implied that most people felt better designing a game with a completely different resolution system), but also locating those rare games where the resolution system was ideally suited for the game - where the mechanics involved supported the game premise (such as is the case with the River in Weapons of the Gods).

  6. Have you looked at the One Roll Engine in Godlike? The quick start rules are in this PDF.

    Nutshell: You get a dice pool of (skill + stat) d10s and look for multiples of the same number to measure success. It adds other dimensions of Width (how many matching dice, used for an action's effectiveness) and Height (the number on the dice, used to determine speed and/or hit location) to give you different scales describing what happens. Multiple matching sets let you do multiple actions. And you don't need to fiddle with math much more than a straight dice pool/tally system.

    I think it's still technically a tally system, but it offers another axis to color the results of an action.

  7. Yah, I know ORE decently well, and it's definitely an oddball, and a very interesting one at that, but it's sort of an edge case of its own. It's got characteristics of a count and a tally system, though I think that in practice it's probably best viewed as a really sophisticated, nuanced count system. Honestly, it might really be its own category, but there are only so many examples of set-building from which to learn lessons.

  8. Am I the only one whose eyes bug out at the sheer mathematical whimsy of dice pool systems? That randomness must somehow increase in bizarre ways in proportion with increase in some other element? Madness I say!

    Give me FUDGE or 3d6 please. For my money, that's the best simulation of reality. I guess that's what I get for taking all of those statistics courses... aversion to probability chaos. :)

  9. As a different edge case, my favorite dice mechanic is from Edge of Midnight (I talked about it a couple weeks ago). It's a variant on the flat roll. The critical difference is that it's two flat rolls, one for stat and one for skill. If both are under the target number, you fail. If both are over the target number, you succeed. If one is over and one under, you partially succeed. This introduces a "Yes, but" layer to the possible outcomes.

    I'm fascinated by dice systems. I particularly want one that can be manipulated in multiple ways by the system (more than just increasing the bonus or decreasing the TN). I also have become a fan of rich systems, where you can pull more information out than a simple pass/fail.

  10. OK, so I did a search for dice and "yes, but" because I want a system that incorporates some element of that. I came across this lovely summary, so thanks. :)

    (And now I need to go check out Edge of Midnight.)

    The real thing is that I want something that allows some sort of "quality of success" mechanic (# of successes, bonus) with a "yes, but". I'm not sure if these are mutually exclusive, but they might be.


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