D&D General A d12 (not d20) D&D System?

[DND_Reborn]

Anyone know if, instead of d20, some one has made a d12 D&D system?

I've tried searching, but everything is about how or when d12 is used in D&D. I've also found some 2d6 systems, but not d12.

 

[Deset Gled]

I remember there being an old thread on this a while back...

And I found it: d12 system: yay or nay?

I'll take copy-and-paste credit for the following suggestions:

Earthdawn 3e
Dominion Rules
12 Degree system from Rogue Games
Mazes and Monsters
Cartoon Action Hour
The One Ring
And also a bunch of board games.

 

[NotAYakk]

A d12 has a variance of 143/12. A d20 399/12, and 3d6 a variance of 105/12.

So in a roll over/under system, 3d6 modifiers away from average are "twice as large" as d20, and d12 are 1.7x as large as d20. (how big modifiers are scales with standard deviation, the square root of variance).

Ie, a system with DCs scaled 40% towards 10, then being 4 lower and modifiers 40% smaller would feel about the same. Attributes from -3 to +3, proficiency from +2 to +4, naked being 6 AC and plate+shield being 12 AC.

We can add +4 to the system by making attributes range from +1 to +7 (no minuses) with +4 being average human. Set proficiency to +2 to +4. DCs are 4+prof+attribute. unarmored is 6+dex, light armor is 7+dex, medium is 11+dex/2 (+1 if bulky), and heavy is 15. Shields grant +1 AC. Magic items cap out at +2 instead of +3. Etc.

...

The interesting thing happens when you add not roll over/under mechanics. Up to that, we just get modifier tweaks. While muliple dice are "curvier", when you reduce it to roll under/over and scale by the SD, the only substantial difference happens in the top/bottom 5%ish (the crit hit/miss territory). Integration makes things smoother, and "roll under/over" is integration of probability.

 

[jdrakeh]

One of the earliest (if not THE earliest) open source fantasy RPGs is a d12-based system called Dominion Rules.

 

[ArwensDaughter]

Coyote and Crow is also d12 based. I have the pdf, but I’ve not played it.

 

[Jaeger]

A d12 has a variance of 143/12. A d20 399/12, and 3d6 a variance of 105/12.

So in a roll over/under system, 3d6 modifiers away from average are "twice as large" as d20, and d12 are 1.7x as large as d20. (how big modifiers are scales with standard deviation, the square root of variance).

Ie, a system with DCs scaled 40% towards 10, then being 4 lower and modifiers 40% smaller would feel about the same. Attributes from -3 to +3, proficiency from +2 to +4, naked being 6 AC and plate+shield being 12 AC.

We can add +4 to the system by making attributes range from +1 to +7 (no minuses) with +4 being average human. Set proficiency to +2 to +4. DCs are 4+prof+attribute. unarmored is 6+dex, light armor is 7+dex, medium is 11+dex/2 (+1 if bulky), and heavy is 15. Shields grant +1 AC. Magic items cap out at +2 instead of +3. Etc.

...

How would this scale if the d12 explodes on a 12, similar to the d10 dice mechanic in CP RED and the Witcher RPG?

I ask because my mathematic ability is horrible, I got lost at: "scales with standard deviation, the square root of variance"...LOL.

 

[dave2008]

A d12 has a variance of 143/12. A d20 399/12, and 3d6 a variance of 105/12.

So in a roll over/under system, 3d6 modifiers away from average are "twice as large" as d20, and d12 are 1.7x as large as d20. (how big modifiers are scales with standard deviation, the square root of variance).

Ie, a system with DCs scaled 40% towards 10, then being 4 lower and modifiers 40% smaller would feel about the same. Attributes from -3 to +3, proficiency from +2 to +4, naked being 6 AC and plate+shield being 12 AC.

We can add +4 to the system by making attributes range from +1 to +7 (no minuses) with +4 being average human. Set proficiency to +2 to +4. DCs are 4+prof+attribute. unarmored is 6+dex, light armor is 7+dex, medium is 11+dex/2 (+1 if bulky), and heavy is 15. Shields grant +1 AC. Magic items cap out at +2 instead of +3. Etc.

So what is the point of revising how or what you roll and then changing all the modifiers to give you a similar experience? Isn't the point to change the experience?

 

[DND_Reborn]

UPDATE:

So, the reason I asked about this was two-fold.

1. To see if it was already out there.
2. Because I am going to make d20 5E into d12 since I find the d20 too broad and swingy. The modifiers are too small for the die size.

FWIW, I am not adjusting ACs or DCs (in general), although what DCs correspond to what task difficulties will be adjusted because the DCs as they are seem sort of silly (DC 5 for a VERY EASY task? Really??).

This will, of course, make a very big difference in the experience--which is what I am seeking. Instead of hitting 65%, for example, it will be closer to 42%. Saving throws will be harder, creating greater impact. I am still keeping the reduced HP I've been doing for a while now, since the bloat won't be needed either.

We shall see how it goes. It might work as I hope, or it might fail completely. Either way, it should be interesting.

 

[GMMichael]

2. Because I am going to make d20 5E into d12 since I find the d20 too broad and swingy. The modifiers are too small for the die size.

There's an old game. I want to say it was called...3rd edition?...that used larger modifiers to keep the d20 happy.

(DC 5 for a VERY EASY task? Really??).

Well, no. There is no roll for very easy tasks. Unless something interesting happens, like the skies rain fire. Then a "very easy" task gets a little more interesting, and the DM can call for a roll.

We shall see how it goes. It might work as I hope, or it might fail completely. Either way, it should be interesting.

I'm pretty sure swapping a d12 for a d20 will solve most of the issues with 5e: players forgetting their Bonds, DMs forgetting to give Inspiration, the whole out-of-sight-but-not-hidden thing. It's great for Bounded Accuracy too - a d12 will keep the numbers lower.

Or you'll get a bunch of confused and angry players, thusly resulting in less free pizza. It's a risk I wouldn't take.

 

[Jaeger]

So what is the point of revising how or what you roll and then changing all the modifiers to give you a similar experience? Isn't the point to change the experience?

It's an interesting thought exercise. No harm in that.

One reason I'm interested in a d12 variant is the D&D systems that were dropped with 3e: Reaction, & Morale rules were 2d6 based.

It should be easy to move those to 1d12 rolls for a true 'universal' system.

Unneeded in the hobby, but seeing as how I homebrew for most games I run now - I'm more into interesting variants for my gaming group.

Because I am going to make d20 5E into d12 since I find the d20 too broad and swingy. The modifiers are too small for the die size.

d16's are more or less readily available - it might be a worth looking into...

FWIW, I am not adjusting ACs or DCs (in general), although what DCs correspond to what task difficulties will be adjusted because the DCs as they are seem sort of silly (DC 5 for a VERY EASY task? Really??).

Kinda why I'm interested in an exploding 12 variant, I'd like to know the math for that before I'd consider using it as a mechanic.

his will, of course, make a very big difference in the experience

I tend to agree. Sometimes changes don't seem like that big of a deal, but during actual play you see the PC's making very different in game decisions.

players forgetting their Bonds, DMs forgetting to give Inspiration, the whole out-of-sight-but-not-hidden thing.

In my opinion: The first two are virtually vestigial systems - Ideas that are half-baked, and thus poorly implemented in the rules. If they were actually better integrated and more meaningful, people wouldn't forget as much... And sometimes a piece of bad game design is just a piece of bad game design.

Don't get me started on "passive" checks...