A new RPG system

Core Mechanics

We’re back and looking at the implications of the mechanic

Okay, so I took a bit of a Hiatus.  Basically all of fall.  It’s not that I wasn’t working on anything Living Myth related, it’s just that I was busy, and uninspired to write.  During the course of that time I’ve smoothed out the core mechanic, thought about its implications, and have been tinkering with writing campaign management software.

What I want to do here is revisit the core mechanic and discuss its implications.



Rationale: The Core Mechanic


This is the first Rationale post.  In these posts we’ll take the mechanics that I’m moving forward with and we’ll scrutinize the rationale behind them.

Today, we’re going to look at the Core Mechanic.  By the Core Mechanic I mean the in game mechanism for determining success, and those other pieces that are tightly bound to it.  For example, GURPS Core Mechanic is “roll 3d6 under skill”, D20’s Core Mechanic is “Roll 1d20 and add Skill”, and Fates Core Mechanic is “Roll 4dF and add Skill”.  In each of those cases I’m over simplifying, but those are at least the core of the core mechanic.


Game Balance and Dice Mechanics

One of the fundamental factors needed in game design is balance.  Of course balance is a funny term that gets interpreted differently by various people, so here I will define it as “A game is balance the same amount of resources (XP, Feats whatever) invested in different ways afford the investor roughly the same amount of impact on the story over the course of the campaign”*

The easiest way to fail at this is to allow a character to maximize one thing with no marginal cost.  Consider this: you have two characters, one has even distributed their resources among all abilities, and another who has simply maximized one.  The latter character is guaranteed to have a larger impact on the story over the course of the campaign.



Further Scrutinizing the Dice Mechanic

Previously we looked at linear Dice Mechanics and I expressed fondness for a 2d6-2d6 system.  Here we’re going to explore this in a little more depth, see what problems it has, what our options are, and work out any kinks.

Some of the questions that come up are, are “How does the range affect play?”, “What happens with Highest Rolls?”, “Who Rolls?”, “How complex is this?”, etc…


How to derive Skill and Difficulty from a Dice Mechanic

In the previous post. I discussed using a 2d6-2d6 dice mechanic, for the purpose of the examples in this article we’ll use that.  What we’re going to do here is explore how the statistics of our mechanics can inform our character traits and target number.  Again, we’ll be leaning heavily on that Standard Deviation.

So, what we have with a Linear (i.e. Roll and Add) dice mechanic is a distribution of numbers that gives us fixed intervals, and a standard deviation.  Working with 2d6 – 2d6 we know we have a range of -10 to 10, with  a standard deviation of 3.42.  From this we’ll first figure out how big each +! is worth relative to that, use that information to figure out interesting statistical information, and finally relate that to probabilities and difficulty.


Scrutinizing Roll and Add Mechanics.

One of the big advantages of Roll and Add mechanics is that they’re linear.  Meaning a +1 always produces the same relative gain in probability.  When the distribution in uniform that +1 always has the same absolute value, when the distribution is normal, the +1 gives the same bonus relative to the unmodified amount.

So to evaluate the different mechanics it’s helpful to discern exactly how much the +1 is going to be worth for each dice and distribution.  The way to do this is using Standard Deviation.


Timing Mechanics

Every well developed RPG has a system for timing actions.  Who goes first, what and how much can they do in their time slot, etc…

The universal approach involves a Round (everyone gets to act) and a Turn (one characters actions).  Exactly how much in done in a turn, and how many turns are in a round is where the details get interesting.

There are many approaches to this, and here I will explore a few and follow with an outline of the system Living Myth will be using.


An analysis of dice mechanics

What does one need to make a good dice mechanic?  What would an ideal dice mechanic look like?

To understand this, consider what your game statistic and dice model in a game you are playing.  Specifically, if you have two characters and the first character has a stat of 10, and the second character has a stat of 12, you know that the second character is better at doing what that stat models than the first character.  So what happens when a person gets “better” at something.  Primarily there are two things:

  1. They become more accurate
  2. They become more precise.


Rejected: First dice mechanic

The first Dice Mechanic idea proposed suffers from some major flaws.  It just doesn’t work.

If you look at the post abut Character attributes  you can quickly see the problem.  Consider someone with the following stat block:


A proposed dice mechanic

One of the things that was usually nice about One Roll Engine’s dice mechanic is that it established two random vectors with a single roll.  For example if a player rolled 3,5,5,6,6,6,7 the mechanics informed us that the roll was a 3×6 roll, where 3 was how Fast/Accurate it was, and 6 was  how Strong/Much it was.  This removed problems of, for example, rolling first to hit and then for damage.  Or worse in some systems rolling to hit, and then location, and then damage, and then figuring out the ramifications of that damage.

Another feature that would be nice in a game is having some ability to control that matrix.  Legend of the Five Rings had some of that with respect to duels, as waiting in duels increased ones effect but reduced ones ability to succeed.  (Or at least that’s how I remember it)

So, here is the dice mechanic I am considering.