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Author Topic: Innovation in Dice Mechanics  (Read 7779 times)

BedrockBrendan

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Innovation in Dice Mechanics
« on: September 05, 2014, 05:35:03 PM »
BY CHARLES MCEACHERN

Dice are a crucial part of (almost) every role playing game. They mediate the divide between player and character, they introduce a sense of tension and unpredictability, and throwing them just feels satisfying. In fact, when comparing different games, the core die mechanic is often the first place we look: Dungeons & Dragons uses a d20, while GURPS uses 3d6, Fate uses 4dF, World of Darkness uses d10 dice pools, and Savage Worlds uses exploding dice of all sizes.

For this reason, when you're brewing your own RPG, the underlying mechanics are an important thing to get right. There's no shame in settling on a mechanic that's been used before, but I do strongly recommend exploring a variety of different options before doing so.

In-game, when a roll is called for, the following questions must be answered; your dice mechanic is the system you use to figure them out.
  • What sort of dice will be used?
  • How many dice will be used?
  • How will success and failure be judged?
This is a brainstorming tool for coming up with your own dice mechanics, but can also double as a critical lens through which to view existing mechanics. Let's go through a few quick examples.

First, look at Pathfinder (or any other d20 system):
  • Action resolution is done on d20s.
  • One die is rolled at a time.
  • The PC's relevant bonuses are added to the result of the roll.If the total is greater than or equal to the roll's difficulty (such as a monster's armor class or a DC eyeballed by the GM), the roll is a success.
Let's also consider World of Darkness.
  • Action resolution is done on exploding d10s.
  • The player throws a number of dice equal to the PC's relevant attribute, plus their most relevant skill, plus or minus any bonuses or penalties that the GM chooses to apply.
  • Each die showing "8", "9", or "10" is a success.
You may notice that in both of those examples (as well as in old school D&D, Numenera, Fate, GURPS, etc, etc), two of the three answers are always the same, regardless of what the PCs are doing, how difficult it is, or any other in-game circumstance. All of the moving pieces are packed into the third.

If you want to come up with something novel, make sure you don't constrain yourself to this model -- there's so much design space you would be leaving unexplored! I would go a step further, even, and recommend that you make sure not to have the players and the GM contributing information to your rolls from the same angle.

When the players and the GM are adding and subtracting from the same number (whether the value of a roll or the size of a dice pool), the penalties and bonuses tend to all cancel out before the dice hit the table. In Pathfinder, an extra +1 to-hit bonus is answered by monsters with higher armor classes; the to-roll target doesn't change. In World of Darkness, awesome characters get larger dice pools, but awesome actions incur larger penalties; the same number of dice end up being thrown. The in-world action is escalating, to be sure, but there's no mechanical escalation to match it.

For an example of a game that doesn't have this problem, check out Savage Worlds.

  • The die size depends on the PC's relevant attribute. Attributes are rated from d4 to d12.
  • A single (exploding) die is rolled.
  • If the result of the roll is greater than or equal to the difficulty (such as a monster's Parry or a number eyeballed by the GM), the roll is a success.
As characters advance in Savage Worlds, they get to roll ever-bigger dice in pursuit of ever-increasing goal numbers (presumably because the PCs are doing things that are ever-more awesome). In terms of raw probabilities this isn't really different from the systems above, but it can feel different. Rolling big dice is exciting because it means your character earned them... and there's nothing the GM can do to take those larger dice away from them.

Similarly, here's the core mechanic from Bloodlines, a homebrew I'm finishing up:
  • The size of die used depends on the GM's assessment of a roll's difficulty. Difficulties are rated from d6 to d12.
  • The number of dice rolled is equal to the PC's relevant attribute.
  • Each die showing "1" is a success.
I would contend that the escalation is even more clear here. Each time they roll, players get a tactile reminder of their PCs' prowess; more dice means, unequivocally, a more awesome character. The GM balances this out by setting the size of dice -- each step up from d6 comes with a significant increase in tension. Even if players and monsters advance in step, and the success rates of rolls are more or less constant, the rolls still feel bigger.

When designing your own game, you get to answer these three questions however you want -- and there are so many answers to explore! Do you want your players to fear large dice? Small dice? Lots of dice? Few dice? Should they want to roll high, low, or specific numbers?

While figuring this out, in addition to the visceral feel of the dice in your players' hands, you'll also want to consider what sort of play you want to enable. Do you want to give the GM the freedom to simulate the details of the in-game world, or glaze over the details in favor of faster rolls?

Traditional RPGs (d20 systems, GURPS, World of Darkness) often have room for the GM to make fine adjustments to the difficulty of a roll based on the situation at hand -- cover, fatigue, special abilities, magic weapons, etc. If this is something you like, make sure your system supports it. If the GM sets the target number for a roll, make sure that target numbers are large, as in the d20 system, so that the GM can use a a +1 bonus or -1 penalty to change the odds of success by just a few percent. Similarly, if the GM sets the size of a dice pool, make sure dice pools are large, so that adding or subtracting a single die is a small difficulty adjustment.

On the other hand, many newer RPGs glaze over the details in favor of making a quick roll and getting back to the story. If this is the style you prefer, make sure there is little room for deliberation. In Fate, for example, most rolls fall between 0 and 8 so the standard +2 bonus is huge. In Dungeon World, there aren't even difficulties at all; players always roll for the same target numbers.



If you like, you can even let your brainstorming get way outside the box. Judge rolls as poker hands, looking at pairs and straights and full houses. Roll a bunch of differently-sized dice at a time. Come up with a set of nontraditional dice, like Fate or Edge of the Empire (I toyed with this idea for a while; see the image above). Run the gauntlet between a game that is distinctive and one that's so weird it scares people away.

I'm not here to tell you what's right or wrong; I'm here to tell you to experiment. Grab some dice, grab some playtesters, and figure out a technique for turning math into fun.

About the Author: Charles is a Minneapolis-based physicist who likes to understand, redesign, and simplify things. He enjoys answering interesting questions, whether or not anyone else cares enough to ask them: Does this game still work without stunts? What happens if I grill these? Can I fix this with a hacksaw? From time to time, these projects end up on his blog, Cooking with Charles.

Bloody Stupid Johnson

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Innovation in Dice Mechanics
« Reply #1 on: September 07, 2014, 08:37:20 PM »
Quote

You may notice that in both of those examples (as well as in old school D&D, Numenera, Fate, GURPS, etc, etc), two of the three answers are always the same, regardless of what the PCs are doing, how difficult it is, or any other in-game circumstance. All of the moving pieces are packed into the third.

If you want to come up with something novel, make sure you don't constrain yourself to this model -- there's so much design space you would be leaving unexplored! I would go a step further, even, and recommend that you make sure not to have the players and the GM contributing information to your rolls from the same angle.

When the players and the GM are adding and subtracting from the same number (whether the value of a roll or the size of a dice pool), the penalties and bonuses tend to all cancel out before the dice hit the table. In Pathfinder, an extra +1 to-hit bonus is answered by monsters with higher armor classes; the to-roll target doesn't change. In World of Darkness, awesome characters get larger dice pools, but awesome actions incur larger penalties; the same number of dice end up being thrown. The in-world action is escalating, to be sure, but there's no mechanical escalation to match it.


I would take the advice here with a grain of salt.
There can be reasons to make various modifications to the core mechanic, but there are dangers associated with this. There are tradeoffs in complexity, handling time and transparency of results that occur and the potential problems should be understood before you do anything crazy and end up with a weird "dice poker" system. Elaborations should be assessed carefully rather than tacked on for the hell of it.

New World of Darkness deliberately abandoned the old version's various ways of modifying the roll where both difficulty and # dice varied, to fix stuff like chance of botching increasing sometimes with number of dice and being 50/50 at difficulty 10 regardless of the user's skill. Shadowrun similarly had varying difficulties and pool size but by 4E went to a fixed target number model.

Also, despite "there's nothing the GM can do to take their larger dice away from them", the GM can take steps to reduce the chance of a more powerful or skilled character succeeding - has to be able to do this. The probability goes down regardless of whether the GM is rolling more dice of their own, increasing the target number, penalizing the size of the dice the PCs roll, or whatever, and multiple sliders here is only making it more difficult to notice, not removing it.

chizarlicious

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« Reply #2 on: September 07, 2014, 11:45:58 PM »
Quote from: Bloody Stupid Johnson;785725
There are tradeoffs in complexity, handling time and transparency of results that occur and the potential problems should be understood before you do anything crazy and end up with a weird "dice poker" system. Elaborations should be assessed carefully rather than tacked on for the hell of it.


Absolutely! Playtesting is crucial to game design in order to keep complexity in check. This isn't a formula for spitting out polished mechanics; rather, it's a way to encourage brainstorming. I'm pretty skeptical of the crazy stuff -- I abandoned the nontraditional dice after they playtested poorly, for example -- but I could imagine someone coming up with a way to make them work.

Complexity and handling time are relative, of course. If you're coming from a bookkeeping-heavy game like Pathfinder or GURPS, it'll be pretty easy to come up with something that feels light. If you're comparing to a rules-light system, the opposite will be true.

Quote
Also, despite "there's nothing the GM can do to take their larger dice away from them", the GM can take steps to reduce the chance of a more powerful or skilled character succeeding - has to be able to do this. The probability goes down regardless of whether the GM is rolling more dice of their own, increasing the target number, penalizing the size of the dice the PCs roll, or whatever, and multiple sliders here is only making it more difficult to notice, not removing it.


This is certainly true -- in fact, I touched on it in that very same paragraph: "In terms of raw probabilities this isn't really different from the systems above, but it can feel different. Rolling big dice is exciting because it means your character earned them... and there's nothing the GM can do to take those larger dice away from them."

Bloody Stupid Johnson

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Innovation in Dice Mechanics
« Reply #3 on: September 08, 2014, 02:35:01 AM »
Welcome to the forum! Good to have more people interested in design about anyway :)

Quote from: chizarlicious;785761

Complexity and handling time are relative, of course. If you're coming from a bookkeeping-heavy game like Pathfinder or GURPS, it'll be pretty easy to come up with something that feels light. If you're comparing to a rules-light system, the opposite will be true.

Both of those I'd call sort of middling at worst in terms of the complexity generated by the basic mechanic itself (3d6-roll-under, or d20 + mods);so I guess you're right that with most games there are going to be a lot of other complications wasting time apart from just the die roll.

Quote

This is certainly true -- in fact, I touched on it in that very same paragraph: "In terms of raw probabilities this isn't really different from the systems above, but it can feel different. Rolling big dice is exciting because it means your character earned them... and there's nothing the GM can do to take those larger dice away from them."


Well this I find a bit idiosyncratic, but then, feelings are subjective.
I've GM'd a bit of SW, played sometimes, and the main reason I like it is that I can resolve a lot of NPC rolls more or less with one big die roll. Compared to Pathfinder, the 'feel' I'm more aware of rolling a d12 is that it can still come up with a 1, while a Pathfinder bonus will reliably make the final number bigger.

chizarlicious

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« Reply #4 on: September 08, 2014, 12:11:32 PM »
Quote from: Bloody Stupid Johnson;785777
Welcome to the forum! Good to have more people interested in design about anyway :)


Thanks!

Bloody Stupid Johnson

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« Reply #5 on: September 08, 2014, 11:56:57 PM »
You're welcome. While you're here, care to tell us about any of your homebrew projects?

chizarlicious

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« Reply #6 on: September 09, 2014, 10:33:38 AM »
Quote from: Bloody Stupid Johnson;785982
You're welcome. While you're here, care to tell us about any of your homebrew projects?


I've got two right now. They are both near completion, but it's hard to find time to work on them.

The first is called Spartan. It's a sort of stripped-down Fate Core set in mythical ancient Greece. I ditched the Fudge dice and poker chips, then added in a light magic system. Spartan has been evolving for well over a year -- it started as a Pathfinder clone but has gone through some massive shifts as a result of research and playtesting. It's on hold right now while I finish up Bloodlines, but you can see a two-page version of it here. The rules are all there, more or less, but it's abridged almost to the point of illegibility.

Bloodlines was originally some bits and pieces that got cut from Spartan (but that I still liked), held together with some generic fantasy flavor. I threw it together for the Top Secret Games Two Page Tabletop competition, and it ended up a lot better than I expected. I've been refining it since then, and it's feeling just about done. I'm hoping to playtest it in the next month or so. If you like you can check out the two-page version I submitted here. It's an early draft, so the ideas are there, but they're pretty rough.

Bloody Stupid Johnson

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« Reply #7 on: September 09, 2014, 08:44:04 PM »
Thanks I'll have a look :)