PDA

View Full Version : d20 + 2d: a (mostly) new mechanic [PEACH]

Alias
2013-01-23, 11:33 AM
I'll try to keep this short. This is a core mechanic idea I've been refining and doing the odds math on for awhile. It's an evolution from d20 where, instead of taking modifiers and, as a result, having target numbers that are constantly moving as the game goes up in level, the character picks up additional dice to roll on checks.

The heart of it all is this: d20 + ability die + (skill die / attack die / reaction die)

So if you're checking a skill, you use a skill die, making an attack - attack die, reacting or "saving" you use a reaction die.

These other dice range from d4 (poor) to d12 (great) at the start of the game. So, like in Savage Worlds, a character might have a d12 strength. They check strength with a d20+d12. When making a climb check where strength is relevant (most of them) the character rolls the die representing climb skill, for example - d20+d12+d6

The target numbers go in multiples of 3 and happily line up with what characters of a certain amount of skill and ability can do roughly 50% of the time. Hence

12 (very easy) - character with no skill and minimum ability succeeds half the time.
15 (easy) - character with minimum skill and ability succeeds half the time
18 (moderate)
21 (hard)
24 (very hard) - character rolling d20+2d12 will succeed half the time. This is also the maximum target number that can be hit with d20+d4, though that requires a 20 and 4 be rolled, odds of this are 1 in 800.

Optional target numbers of 27 and 30 can be used. Because the system uses multiple dice, odds of success bell curve...

Got all that?

K, next wrinkle. What comes after d12? What is the strength of an ogre? A giant?? A dragon???

Savage Worlds uses ability bonuses to answer this, but that reintroduces target number inflation. What I've played with is adding additional dice. The next "score" beyond d12 is d12/d4, taking the highest roll between the two dice. Each time the skill (or ability or whatever) is promoted the new die goes up -- d12/d6, d12/d8 and so on to d12/d12. That is the strength of an ogre. A giant takes the best of 3d12 rolls, and a dragon the best of 4d12.

There are two upshots to this. First, the target numbers remain consistent - but the odds of success improve. The improvements become more marginal though - the difference between 3d12 take best and 4d12 take best isn't as much as d12 and 2d12...

But they can be costed the same - which is nice on point buy. A lot of systems have to change how many character points you spend to raise a high score even higher - for good reason. Characters are encouraged to diversify their skills at high level rather than break the game in half in one or more ways. With this system each point spent in a skill gives diminishing returns.

But there's more wrinkles I've found.

One is the tricky area of knowledges. Which sounds better - I have 3d12 in Science, or I have d12 in Physics, d12 in Chemistry and d12 in Engineering. If my character is doing something that all three skills apply to, simply roll all the relevant skill dice and pick the best result.

At this point in the system's evolution I've worked out how the mechanic works and I'm working on the costing of the three check types - attacks, skills and reactions. In d20 reactions and attacks are locked to class as they give a strong indication of character combat survivability. The locking to class also prevents players from neglecting them while building a character.

Their costing should be different and higher than the skill costing. To have a reference point, the raising of a skill from one die to the next should cost 1 point.

My plan is to work out the character point framework, then set the class / level system on top of that as a simplification layer. This should be much easier than deciding what the classes do first and then trying to convert back to character points.

Ok, I'll stop here and wait for comments, if any. With completely new systems, that's largely a crap shoot. Thanks for reading.

PEACH
2013-01-23, 12:30 PM
This works incredibly poorly if it is intended to work with D&D 3.5 or using D&D as a base for so many reasons it should be blatently obvious, but AC, skill bonuses, buffs, and save forcing effects do not play well with this system at all without a total system rewrite that accomplishes hardly anything but making higher level characters less likely to hit anything.

If it's just the backbone of a standalone thing... eh. Doesn't really solve too much besides basically reaching an arbitrary point where specialization becomes worthless and you're essentially at "max power," which I suppose could be useful. I feel like it is a much better idea to figure out what you want your theoretical system to do and whether or not characters specializing heavily is something you have a problem with before you figure out the dice rolling system to counter that, though.

Grod_The_Giant
2013-01-23, 12:44 PM
Important question: why is there still a d20 roll in there? The results it produces are going to be large enough and varied enough to overshadow whatever ability and skill dice you may roll.

tarkisflux
2013-01-23, 01:32 PM
Important question: why is there still a d20 roll in there? The results it produces are going to be large enough and varied enough to overshadow whatever ability and skill dice you may roll.

Along the same lines, why not 3d6 (more bell curved and less varied) or 1d10 (smaller and less likely to overshadow skill and ability) instead of 1d20? It seems like there are better thing you could use to model the inherent randomness of an action.

Edit: Also, odds of d20 + d4 = 24 are .05*.25 = 0.0125 or 1/80, not 1/800. They aren't likely, but they're not that unlikely either.

TopCheese
2013-01-23, 01:53 PM
As others said, the D20 overshadows the rest of the modifiers.

Most of the time as soon as you roll the d20 you know if you will pass of fail.

Think of this like initiative, in 3.5 + newer I have seen countless times where the heavy armor dex penalty can react faster than a guy in leather armor and a +5 dex mod.

Alias
2013-01-23, 02:05 PM
Important question: why is there still a d20 roll in there? The results it produces are going to be large enough and varied enough to overshadow whatever ability and skill dice you may roll.

That is nonetheless intentional. I like the variance of d20 without the target number inflation that static bonuses impels. I'm currently running an 11th level pathfinder game. The DC's I was using at 1st level are now meaningless and I find myself reading the die and not giving a crap about the modifiers anymore in order to keep the game moving smoothly.

At it's heart this system only needs me to pick one of three difficulties - easy (15) average (18) or hard (21). It should play perfectly well at any level though higher level characters will succeed at the hard stuff more often.

Maybe this is why Savage Worlds doesn't use the d20. The moment you include one people presume the system is supposed to work exactly like D&D/d20/Pathfinder. That isn't the case here.

There is a system called Cortex that lops off the d20 and just has ability+skill die, and that in turn is derived off Savage Worlds. But in playing the latter system for nearly two years I've come to find its simplicity to be more straightjacket than fun. When your only die to cast is a d4 and your modifier is +1 that's enormous. As a GM you have no real choice but to either give an enormous 25% buff at a minimum for the fledgling characters, and for the veterans with a d12 it isn't as effectual - worse that +1 is more valuable to get than graduating the die in nearly all cases (especially considering that system's ace rule).

ngilop
2013-01-23, 02:05 PM
So, you basically want what Alternity had, only a tad more convoluted?

Alias
2013-01-23, 02:59 PM
So, you basically want what Alternity had, only a tad more convoluted?

???

Here's the wikipedia description of Alternity - having played it, I'll vouch this is pretty accurate.

Characters were created with a point-based system, and could be either humans, mutants, one of several alien species presented in the core books, or original aliens created by the GM. Classes were replaced by professions, which dictated what skills and abilities were cheaper for any given hero to get, though a few skills (in particular, psionics) were restricted to specific professions.

Skills are classified into broad and speciality skills. Earning a specialty skill requires an associated broad skill, which requires a character to have sufficient associated ability points. Special skill is further classified into ranks, which affects the skill's scores. Skill scores are presented with the full score, half that score, and one-quarter that score. which represent the numbers needed to achieve Ordinary, Good, or Amazing successes in an action round respectively.

Unlike many other systems, actions are determined by a control die and situation dice. When Gamemaster calls for a roll, player rolls 1 control die and 1 situation die. The control die is always a 20-sided die, while situation die can be a 0, 4, 6, 8, 12, 20-sided die, where 0-sided die means the action only depends on control die roll. Situation die can be plus die or a minus die, in which the value in the situation die is added to or subtracted from control die value. The total of the rolled numbers is checked against character's action, skill, feat, to indicate a success or a failure. Rolling low is always better for successfully completing an action.

The type of situation die being used depends on the difficulty of the action. Difficulty is scaled in die types of -d20, -d12, -d8, -d6, -d4, +d0, +d4, +d6, +d8, +d12, +d20, +2d20, +3d20. A character's base situation die is +d4 for broad skill or feat check, +d0 for specialty skill or action check. A minus situation bonus means player uses a larger negative situation die set, while a plus situation penalty means a player uses a larger positive situation die set.

In an action round, a round is divided into 4 phases. Each phase relates to one of the degrees of success that are achievable on an action check: Amazing, Good, Ordinary, and Marginal, in order from the first phase to the last. A hero can attempt only 1 action per phase. Acting orders of characters are determined by a d20 die roll for all participants, which determines the earliest phase in which a character can act. All actions in a phase are considered to occur simultaneously, with the results of those actions being applied at the end of the phase. A character can act in as many phases as it has actions per round.

Depending on how far below the skill score the player rolled, there are 3 progressively better layers of success and 2 levels of failure. An action is determined using this same system, making the game very uniform. Only armor rolls and damage rolls did not use the d20.

The wiki also fails to mention that Alternity is one of those rare "roll as low as possible" systems, so higher is worse (-3 bonuses and +4 penalties abound in it)

So you're telling me what I typed up above is more convoluted than one of the most disastrously convoluted systems this side of Paladium Games (Cause honestly, RIFTS is the only system I can think of more ill thought out and convoluted than Alternity)

I mean, honestly, I consider that comparison to be downright insulting sir.

ngilop
2013-01-23, 03:19 PM
Ive played ALternity and was beyod saddened when it was cancelled as I feel it was teh best system devopled.

so becuase you system is the same thing as ALternity excpet you trying to get X number and over instead of X number and under. its so much vastly superoir?

now that is insulting sir or madame.

Alias
2013-01-23, 03:30 PM
Ive played ALternity and was beyod saddened when it was cancelled as I feel it was teh best system devopled.

so becuase you system is the same thing as ALternity excpet you trying to get X number and over instead of X number and under. its so much vastly superoir?

now that is insulting sir or madame.

I shouldn't even try but...

Any system that has both negative and positive dice to modify a roll is more convoluted than a system that only adds the dice...

Static target numbers are simpler than target numbers that move according to skill...

One degree of success is less complicated than four...

For whatever reason human beings add faster than they subtract, so yes, its less convoluted to have a 'roll high' system...

It is flat out anti-intuitive and yes, convoluted, for a bonus to be expressed as a negative number and for a penalty to be expressed as a positive number...

I can go on if you like. Alternity was not a good system. If you find that insulting, too bad.

tarkisflux
2013-01-23, 05:21 PM
That is nonetheless intentional. I like the variance of d20 without the target number inflation that static bonuses impels. I'm currently running an 11th level pathfinder game. The DC's I was using at 1st level are now meaningless and I find myself reading the die and not giving a crap about the modifiers anymore in order to keep the game moving smoothly.

At it's heart this system only needs me to pick one of three difficulties - easy (15) average (18) or hard (21). It should play perfectly well at any level though higher level characters will succeed at the hard stuff more often.

This doesn't answer the question of why you aren't using a different base die (or dice) instead of the d20. I get that you don't like static modifiers, but you've already removed them and replaced them with strongly capped variable bonuses.

What you are proposing here is a system where dumb luck that anyone can bring to the table is almost always more important than their skill and ability. If it's not obvious why that is the case we can talk about it, but I'm worried here that it's not an intentional design decision on your part.

So I guess I want to know "what does a d20 do for the base luck aspect that other options don't, and why do you prefer those?"