Let's Talk About Core Game Mechanics

[Thomas Shey]

By masters, do you mean mechanics?

No. I meant "who will this mechanic serve the needs of?" Some mechanics really work for some people with some aims and some really work for others. Thus they "serve different masters".

 

[Fenris-77]

No. I meant "who will this mechanic serve the needs of?" Some mechanics really work for some people with some aims and some really work for others. Thus they "serve different masters".

Definitely. RPGs and their mechanics have a purpose for writing just like any other kind of writing. In this case a more or less specific play experience.

 

[aramis erak]

A little background: I have been having some recent "wake up call" cardiac situations, which has motivated me to finally take some things off my Creative Bucket list. I have been freelancing off and on in the TTRPG space for 25 years, but one thing I have never done is design my own system. Creating an RPG is definitely a bucket list item. Do this thread is the first in what will likely be a bunch of threads over the next months trying to drill down on a design.

This thread is about core game mechanics: the foundational mechanics of a game that define how stuff gets done in the fiction. they can be simple like "roll a d20 and add a number, compare to a target number" or complex like "build a pool of dice for various abilities, roll, and count the successes then convert those into results." And of course, not all games use dice or randomizers at all, and some games with simple core mechanics are made complex by whatever lays overt them.

I am interested in getting a sense for what people like about a "good" core mechanic. What makes a "good" core mechanic, anyway? What are some of your favorites from various games, and why? Have you ever like a core mechanics but disliked the system as a whole? Vis versa?

As an example of my own, I really like the core mechanic from the Ironsworn games: roll a d6+mods, then compare to 2 separate d10s as target numbers. You can get no success, partial success (beat one of the d10s) or a full success (beat both of the d10s). I do not really if there is a critical system, but I don't think so, nor do I think it needs one. I like that the systems is a little chaotic and unpredictable, as well as the built in multiple degrees of success. One think that could be interesting is to add a Daggerheart "Hope and Fear" style "tenor" element. You could designate the d10s as a Complication die and a Opportunity die. Any time you get a partial success, you further interpret and impact the result based on whether you bet the Complication die or the Opportunity die.

Anyway: core mechanics. Talk to us.

Man, skip a day or two and threads get LONG...

For me, the nature depends upon what the system models... what's right for Star Wars isn't what's right for Star Trek... Star Wars needs the chance for epic side effects, for weirdness to happen. In WEG, that managed (barely) with the Scaling and the Wild Die rules... with FFG, the custom dice gave that same whacky anything-can-happen-within-reason feel. Two, totally different, yet equally potent approaches.
Trek, on the other hand, needs to be more about effort being rewarded; this is why I think FASA, good as a simulation of TOS combat as it was, fell flat outside that - no room for the system to recognize effort and help... and 2d20 STA manages to reward helping and effort, via the metacurrency systems... STA isn't perfect for Trek, but it's good enough to feel right.

Ironically, I feel that Trek would be best served by Cortex Prime... Effort, via plot points and adding additional assets and skills, as a sign of effort.

Star Wars is about being where you're needed and naughty word happening to and around you.
Trek is about overcoming the plot of the week's major obstacle... and the systems for it that do it best are LUG and STA of the published games; STA does it better than LUG, which does it better than Decipher, and all three better than FASA... Prime Directive does Trek as Trek sorta poorly, but it does Starfleet Seal Team the Trivid beautifully. It's better than FASA or Decipher, IMO. GURPS gets both entirely wrong for me - it doesn't have an effort cycle at all, and it has a 6 stage outcome, but it's single axis, so GPD not only fails the Generic Trek game, but due to choices of the IP holder for the SFU, can't do all the things which are important to trek, as it denies access to ships as part of play in GD.
And GURPS outcomes are far too mild for the wild that Star Wars should have.
I can see why people like doing Star Wars with Savage Worlds… but in so doing, they seem to be increasing the value of raises beyond what the SavW mechanics suggest... tho' for a pure Rebel Squadron game, I could see it; that's a very narrow subset, and I'm one who likes the wilder side of TCW/CW, Bad Batch, and Rebels... and Eps 1 and 2. Even as I hate Darth Jar Jar in all his silly, I like the tone of BB and TCW/CW... and the slightly less silly and more epic Rebels... I can't see doing those with SavW... as written. Especially the extremely broad competence of Ep 1-2, ep 4, BB, TCW, CW, and Rebels characters... tho' solving that? Change the Wild Die from d6 to dAttribute... and no unskilled penalty. But then it's not SavW anymore... but a close variation.

For grim and gritty, I like percentile systems... no nonsense, know your odds going in...
Grim and Silly, again, percentiles, but with obnoxious crit charts and extreme chances of criticals - a la WFRP, Dark Heresy, or Deathwatch.

For total silliness, 2d6 with plenty of silly chart options, exemplified by KAMB... and it's sibling, the SAKE system version of Ninja Burger.

 

[aramis erak]

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.
2. As a way of conveying additional information about a "roll."
3. 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.

My favored use of cards is that you have a hand and thus can pick which of the next several "rolls" result will be. Best in opposed resolutions, IMO, as that prevents a firm fixed TN, and thus is about odds, not knowing pass or fail ahead of time.

Also fun to try: in systems with a single die roll type, have them roll 3 sets, then have to pick one of the three for their first action, then another from it for their second, and finally, their third is the remaining pool... then once all three are used, reroll to generate three more... this mirrors the way CF plays using a circa 2003 post by Mike Pondsmith on the issue of when to redraw...
he gave three options: draw one after every resolution, no matter how many cards were played, and refill end of scene; option 2 redraw when hand empty; option 3, redraw as many as used. Several others suggested redraw only at end of scene; note that one may always use the top card of the deck unseen... so out of cards means random draws. I preferred draw 1 after each action, redraw full after a rest, redraw 1 extra at end of scene...
... which results in an effort mechanic.

Skill 80 = 80% doesn't take into account the difficulty (or armor class) of the challenge, nor situational modifiers. And personally I don't like RPGs that ignore those things.

Neither do I. Which is part of what bugs me with AW and most AWE and especially the "truely PBTA" subset with its 2d6+ability vs 6-9/10+...

[mention made of one's martial training making hero system feel suitably simulationist]

Seriously. That's IMO a very hot take.

As an SCA Fencer and former Heavy, and having studied combat archery, too, as well as some Iaido/Iaijutsu (but not the rest of Kendo) and some Kung Fu... I feel very much the same about Martial Hero for HSR4/5... it leads to a pretty fun simulation with just enough abstraction to not bog down.

Hero System is particularly well balanced between simulationism and narrativism.

 

[aramis erak]

On the wide vs narrow skill front... I find myself wanting a few more in Alien (it has 12) - but being ok with only 5 for Dune 2d20 and 6 in STA 2d20... because of the wide range of specializations to focus them in both 2d20 system games. I was less happy with Fallout and it's longer list without specializations.

 

[Reynard]

One thing we haven't really talked about is games WITHOUT a strong core mechanic. This is less common today, but for example AD&D lacks a core mechanic. Although it uses a d20 in a lot of its mechanics, it uses it differently in each: roll high on a table for attacks, roll low on a table for saves, etc... And many of the other basic resolution mechanics in the game don't use a d20 at all: use a d6 to find secret doors, roll 2d6 for morale. Sometimes, EGG just gave a range of probability without even indicating what dice to roll.

 

[Barner Cobblewood]

Can you explain what you mean by "explode in a linear way"? Example mechanic?

Another roll that doesn't produce a bell curve, e.g. players roll 3d6 for success or failure, but on natural 3 or 18 roll another die e.g d8 to add/subtract to their result. D66 etc tables are also linear. This could make some situations "cinematic" and entertaining. In this example about 1% of the situations would be spectacular. Helps create stories for the table to reminisce about.

Alternatively the roll could be used to describe an additional "critical" outcome.

I like tables because they reassure the table that personal favouritism among players is not driving how the event will affect the N/PCs. They also permit solo playing that can be folded in with table play.

Obviously this mechanic is for games developing out of the wargame/d&d tree. I don't have a lot ofexperience with other families of role-playing games, but I think if I wanted to play a "create a story" game at a table the mechanics would be about delimiting and ordering player input.

 

[Gorgon Zee]

Sure, but I also see barely any daylight between that and "DC is 14 and you have a +2".

I think the original implication was that people have a better intuitive understanding of odds expressed as percentages rather than ratios (e.g. 40% instead of "8 out of 20") but in my experience people suck at genuinely understanding either.

Actually, my original point was that LINEAR dice-rolling systems are easier for players intuition. D100 vs d20 is not an issue, it’s that if your (modified) skill is 80% you don’t need math to get a good feel for how likely you are to succeed, whereas if you are told you need to roll 2 6’s on 8 dice, or hit 15 with 4d6 it’s likely to draw you out of the game and require math. Hence my preference for a linear rolling system and non-linear mapping to results, like BRP

 

[Reynard]

Actually, my original point was that LINEAR dice-rolling systems are easier for players intuition. D100 vs d20 is not an issue, it’s that if your (modified) skill is 80% you don’t need math to get a good feel for how likely you are to succeed, whereas if you are told you need to roll 2 6’s on 8 dice, or hit 15 with 4d6 it’s likely to draw you out of the game and require math. Hence my preference for a linear rolling system and non-linear mapping to results, like BRP

Players' ability to intuitively judge probability, at least roughly, is definitely important for player agency. And I agree that linear distributions make that easier.

I can't remember what game it was off the top of my head, but I swear I saw a character sheet with the dice pool probabilities printed in a little chart for reference.

 

[Thomas Shey]

One thing we haven't really talked about is games WITHOUT a strong core mechanic. This is less common today, but for example AD&D lacks a core mechanic. Although it uses a d20 in a lot of its mechanics, it uses it differently in each: roll high on a table for attacks, roll low on a table for saves, etc... And many of the other basic resolution mechanics in the game don't use a d20 at all: use a d6 to find secret doors, roll 2d6 for morale. Sometimes, EGG just gave a range of probability without even indicating what dice to roll.

Well, I'm on record as saying I don't think this ever serves a particularly good purpose. In particular, of you're just substituting a single linear die with a different one, you could get close enough to the same probability other ways. (There can be a coherent argument made for reserving a multi-die system for some functions and not others, but I'm not convinced its worth it).