Let's Talk About Core Game Mechanics

[Bill Zebub]

For any dice mechanic, there is the distribution of the dice results, which typically are linear (e.g. d100), bell-curve (e.g. 3d6) , or some form of long-tailed (e.g. exploding dice). And then there is the mapping of numeric results to the game-world results, which can be varied, but generally look a bit like this

• target number is all you care about
• target number with a potential critical success
• target number with critical success / fumbles
• various target numbers determining degree of success.

d20 is one of the simplest systems - linear results, target number + criticals. That's why it's good default. The bad thing is that everything is linear, so your chance of a critical is independent of your chance of success, which is not tremendously realistic.

Yes, this is one of the things I find very weird about d20, crit on 20: if you need a 19 to hit, then if you do hit, 50% of them will be crits. Completely counterintuitive.

The One Ring is an odd example where there are two separate systems being used at the same time with the same dice roll. One is a simple bell curve where you roll a bunch of dice and compare to a target number to determine success, and the second is where you count the number of 6's rolled on the 6-sided die to determine degree of success, conditional on the first evaluation being a success (there are some extra fiddly bits with rolling 1's and 12's). It should be annoying, but in play I've been quite happy with it, even though I have little intuition on what a likely outcome is.

Same. Upthread I flagged it as the core dice mechanic I've most enjoyed.

If you go for non-linear rolls + non-linear results, it's hard for people to get a feel for what the expected outcome is likely to be, and that is an immersion-breaker as we'd expect our characters to have that knowledge.

I'd be careful categorizing things as immersive or not. Some people find it immersion-breaking to understand the math because, for them, it pulls them out of the story and into the mechanics.

Anyway, even if I'm an expert swordsman I couldn't tell you the odds of my attack landing against a new, unknown adversary, except in the most general sense. So at first glance I disagree with that premise.

 

[Bill Zebub]

true, but I am not aware of any games where the average result leads to the more unusual outcomes. You either hit or miss, depending on the target value, but you neither critically fail nor critically succeed, so it generally will be among the most 'normal' and definitely most common outcomes possible.

From my understanding that was the OP's complaint, that a bell curve makes the more exciting / interesting stuff less likely to occur compared to a linear distribution.

Maybe that poster is assuming the same DCs are used? A DC 16 on a d20 is (approximately) equivalent to a DC 13 on 3d6. Both are only 25% likely to occur.

To convert those probabilities into d20 you'd have to "stretch out" the numbers (e.g. the 13s becoming 16s), but any results of 3, 4, 17, and 18 represent probabilities that can't happen on d20.

 

[Kannik]

d% is fine but it's too much false precision, IMO.

I concur here... I got my start on d% and it was my go to for years for linear resolution until I started to get that same feel, where 5% increments (d20) is enough granularity and speeds up calculations immensely.

In my opinion, it’s not about normalising people. It’s about having a more normalised set of outcomes.

* I am aware that this phenomena is why some people dislike non-linear distributions. Different folks / different strokes.

Also why I prefer bell-curve systems. Can still have outliers for excitement and disappointment/trouble, but they are outliers. (Which for me has the bonus effect of heightening their excitement/disappointment.)

d20 and Fate are the only two systems I play regularly that are all linear. Like @Bill Zebub I do like to see non-linearity in results, but I also like the simplicity of linear dice rolling, so for me the sweet spot is a linear dice roll and non-linear results -- and I think BRP has the best approach I have seen for that. Anything more complicated, and there has to be a big thematic payoff for me, otherwise it feels like the system is trying to obscure its mechanics.

Hmm, by chance did you mean a different system other than FATE here? Fate's 4dF roll produces a bell curve

 

[Reynard]

This is really neither here nor there, but while I don't particularly like or dislike 3d6 for action resolution (I was a Champions player) I much prefer making my random encounter and other charts on 3d6. That's where the bell curve shines IMO.

 

[bsss]

Given the number of people who have argued that "a +1 bonus only makes you 5% better in combat" I think even a linear 1-20 is pretty hard for a lot of people.

Also, I'm not sure the precision really matters. Nobody will notice the difference If you make something 3%, 7.5%, or 11% easier.

You're not wrong. To some degree I feel like my role as GM, even with the linear system, is to say "let me worry about that". Not that I'm trying to gatekeep their system mastery or anything, but at some point it all boils down to trust that I'm setting sensible DCs and picking the right challenges, relative to context, feel of risk, etc. Linear = easy, low fret, even if misunderstood.

 

[...m...]

d4s make me sad. (Sorry Caltrops RPG)

...arch d4s are pretty great, especially when you throw a whole fistful of damage...

 

[Thomas Shey]

Given the number of people who have argued that "a +1 bonus only makes you 5% better in combat" I think even a linear 1-20 is pretty hard for a lot of people.

Also, I'm not sure the precision really matters. Nobody will notice the difference If you make something 3%, 7.5%, or 11% easier.

I think that's true as a one-off. I think people can start to very much notice it if its repeated over time (say, as a modifier for a common but not constant situation).

 

[Thomas Shey]

true, but I am not aware of any games where the average result leads to the more unusual outcomes. You either hit or miss, depending on the target value, but you neither critically fail nor critically succeed, so it generally will be among the most 'normal' and definitely most common outcomes possible.

Eclipse Phase can. Because of the way its special and critical results are calculated, you can very much end up with an average roll that produces a non-average output. Crits in particular are scattered across the whole of the die roll range (essentially in its percentile resolution, its when you roll doubles; if those doubles are above your success chance they're a critical failure, if they're within it, they're a critical success).

From my understanding that was the OP's complaint, that a bell curve makes the more exciting / interesting stuff less likely to occur compared to a linear distribution.

That isn't even necessarily true with more mundane approaches. If the chance increases with the success chance, it can very well be that special results occur more commonly when that builds up with 3D6 than a D20. That entirely turns on how much chance of that the design wants. For example, a 3D6 roll where half of the target number is a crit will still be pretty low if the roll needed is 12 the chance of rolling that 6 is about 6 and a bit percent, but when the roll has risen to 16, the chance will have increased to 25%. That's just a question of how often you want those special results.

 

[Thomas Shey]

1. I haven't played many dice pool games. Am I insane for wanting to roll add them instead of counting the ones that hit max value or something? Like roll a fist full of d6s, then add all the results. Hell yeah.

There are dice pool games that do that. The traditional Star Wars, WEG D6 style games did. You just have to want to play with the large numbers that result from doing that.

I would love to see more mechanics that involve cards. I feel like cards are severely under utilized.

1. As replacement for dice. Because it's nice sometimes to know that the number you just drew won't or less likely to show up next.

I've characterized this as "resolution with memory".

1. A hand or a deck as a way of tracking what your character can or cannot do, maybe like Ironsworn assets. Maybe there is an elegant way to represent health, status ailments, character evolution (a little more concrete than say, tags) using a hand or a deck.

To some extent the TORG/Masterbook/Shatterzone card deck did this.

 

[Thomas Shey]

Yes, this is one of the things I find very weird about d20, crit on 20: if you need a 19 to hit, then if you do hit, 50% of them will be crits. Completely counterintuitive.

There's a reason that some D20 games that use a 20 as a crit (I think D&D 3e might have done that, but its been a long time) have a follow-up "success" check to go with it.

I'd be careful categorizing things as immersive or not. Some people find it immersion-breaking to understand the math because, for them, it pulls them out of the story and into the mechanics.

And you have weird in-between cases. I've got a player who never found dice counting of any stripe, or applyng the numbers interfered with her immersion, and expenditure of metacurrency she could get around, but the TORG card play pulled her right out (probably part of that was she had vision problems).

Anyway, even if I'm an expert swordsman I couldn't tell you the odds of my attack landing against a new, unknown adversary, except in the most general sense. So at first glance I disagree with that premise.

Yeah, but I bet after a few rounds you'd have some sense of it, and if not conveyed with numbers in a game, then what?