[Homebrew] Bye Bye Twelve-Sided Die

Last week I talked about my ideas for an stat system for the RPG I’m designing. Since then, I’ve talked to a few people about my ideas and I’ve had a proper think on the subject. I ended up doing some mock rolls and firing up the old spreadsheet to get an idea of the probabilities and as it turns out, it’s not really workable. If you’re interested in the process, you can see some of my notes here.

A sad D12
Pictured, a D-12 after learning they would not be used in a roll-under system.

What I ended up realizing is that for a roll-under system like what I had in mind, good old D12 just doesn’t have the range necessary to be a good fit for a roll-under system. The delta between a 50-50 chance and nearly impossible to fail is only 6 points and given that I want characters to at least feel competent, that puts the range of stats characters can have in a very narrow band.

So, keep what I learned, throw everything else under the bus and start over. I suspect that will become a theme as I write this system. Come up with an idea, give it a test and then chuck it out for sucking. So on to idea v0.2

So my first idea didn’t go great. Alright, before I launch into another half-baked idea, perhaps it’s a good idea to figure out what I want my dice system to do exactly. After all, it’s very hard to design something if you don’t know what it’s supposed to do.

First: the act of making a test should be straightforward and simple. It shouldn’t be much more complex than adding two numbers and rolling some dice. Or rolling some number of dice (ideally less than seven) and comparing them to a number.

Second: explaining how to make a test should be straightforward and simple. This is different from the previous one as this concerns itself with how to set up a test.
The best example of my first and second requirement are D&D 3.5 and Cthulhutech.
In 3.5, explaining the test is real easy. How do you make a test? roll a d20 and add your relevant modifier (usually, attribute + skill + misc). Actually making the test is kind of awkward since you can have up to a dozen different modifiers, each of which you need to remember somehow.
In cthulhutech, explaining the test is kind of awkward. You make a dicepool based on your skill and once you’ve rolled it, you figure out your result based as follows. Your result is either: the highest number rolled OR add together all dice that came out the same OR add together a sequential series of dice. And you still get to add dice afterwards by spending points. Surprisingly, making the roll is fairly simple as the human brain is pretty good at figuring out matching sets or sequences among numbers from 1 to 10.

Crit a cyclopse, be a hero!
You can bet your ass David’s player felt awesome for beating that CR 12 cyclops with his second level character.

Three: I want some sort of critical hit system in there, something that lets you go above and beyond your normal capabilities and provokes that ‘YEAH’ moment in gameplay. D&D has the perfect example in critical hits where you might have a snowball’s chance in hell of actually hitting a boss but rolling that 20 not only guarantees a hit but deals double damage!
Anima and savage worlds have a similar mechanic where dice explode when you roll high enough on them, producing situations where untrained people can pilot nuclear submarines or punch out gods. It feels great and keeps things tense.

Fourth: I want characters to be reasonably predictable in their abilities. I don’t want a master blacksmith to have a 20% chance of fucking up shoeing a horse, nor do I want a character to be equally likely to punch out a god as they are to fumble, fall and break their neck. While these examples are a bit exaggerated, the idea is there. If a character is good at something, they should be good at it all the time, not 10% of the time.

I’m aware of the fact that point three and four are kind of at odds with each other but they don’t have to be.  A roll-under system that uses 3d6 (HeroSystem) is both consistent with regards to character’s abilities and can have those crits that I want (rolling a 3, for example)

With all of that out of the way, I’ve done some brainstorming and here’s what I’ve come up with. I’ve decided to stick with the d12 and I’ve decided to stick with the roll under method. What I’ve changed is how the values are treated. A character’s stats are no longer an absolute value. Instead they will be compared to a difficulty and that will determine the number to roll under.

Let’s example this. A character has a stat of 4 for whatever they’re trying. The difficulty is 4. We compare these values and see that they’re identical. Identical values means they roll 8 or under. If they get that, success. If they get more, failure!
A character with a higher skill would have to roll under an 9 or even a 10, depending on the difference and similarly, a lower skill character would have to roll under a 7, 6 or even 5. The exact progression for these values will have to be looked at  but I think this is a promising system so long as the ratio of difficulty modifier to skill/difficulty is predictable and not too complex.

I’m also keeping the idea of characters with superhuman abilities having it easier. They will get to roll one or two additional dice, both having a better chance at success and a chance at more successes, accomplishing feats far beyond normal people’s abilities.

As a last addition, players will be able to expend some resources (Stamina) to generate additional dice. This will likely come in mostly during important scenarios but it’s another method of modifying rolls.

So for a conclusion, let’s test this to my four requirements.
One: Making the test is simple. Roll your dice, see if you got under the number you needed. There’s a bit of looking up to determine the number, but I suspect that will just take a bit of getting used to.
Two: While certainly not perfect, I don’t think explaining the system is terribly complex. No more than something like White Wolf’s Storyteller system or something like shadowrun.
Three: Crits. 1/12 seems like a pretty reasonable chance for crits, rare enough that they won’t happen all the time but not uncommon.
Four: predictable. A character with a high skill level will get relatively easy rolls on anything but the toughest challenges and even for those, they’ll have it easier than those with lesser skill.

Tests passed, I think this will work nicely.

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