Hello Forgers,

So, I've been bouncing around the Forge for the past couple of weeks and have received a first-class education on RPG design. Now, I'm faced with several interesting challenges for my fledgling system--whose working title is called Aspect.

The first challenge I want to address is the dice mechanic. Before I describe it, though, let me give you a quick overview of some facets of the system:

* It will be a Gamist/Simulationist system that requires a GM, but there will be mechanics for players to influence/control some aspects of the story and plot.

* I am currently focusing on the rules, but plan to adopt these rules to three settings: modern, fantasy, and science fiction. I have ideas for these settings and am building hooks into the core system to accomodate these ideas; I will expand on these areas when I begin focusing on the settings.

* My goal is to have a working alpha of the system by the end of July. I will take a short break from game design before conducting some system tests; System testing and revisions will probably last for 3-6 months or so and then, after another short break, I will begin working on settings.

* All rolls are opposed totals per [URL=http://www.indie-rpgs.com/viewtopic.php?t=2695&postdays=0&postorder=asc&start=0]Mike's Standard Rant #5: The Myth of Opposed Rolls.

* It is a skills+specialty based system. For example, I may have a skill called Charm with a specialty under Charm called Seduce. When I make a Seduce total, my levels in Charm and Seduce form my Ability Score.

* Attributes allow players to influence/control some aspects of the story and plot; I have not yet decided whether they will add to Ability Checks.

* There are degrees of success and failure; the higher total wins the contest, but the degree of success is measured for every x number of points the higher total is over the lower total. This number is called the Up Count and will vary between 2 and 4 depending on a variety of factors. For example, if Sally tried to seduce John, she would make a Charm+Seduce total and John would resist with his Resolve total (he does not have an appropriate Specialty to use in his total). If Sally were to win the contest, her Up Count would be 3 because she has both a Skill and a Specialty. If John were to win, though, his Up Count would be 4 because he only has a skill.

* You receive an Up every time you exceed the opposition's total by the Up Count; So, if my Up Count were 3 and your total was 4 and my total was 12, I would receive two Ups, which will allow me to do some nifty things(tm). Not all of these nifty things(tm) have been fleshed out.

* Skills and Specialties can only advance through use, which means that experience points are only gained by performing well or poorly--basically performing in such a way that you learn something new. This is measured by rolling well or rolling poorly. When you earn an experience point, you will assign it to the skill or to the Specialty used for that total. Once you have gained enough experience points for that skill or specialty, it will then be able to level-up.

* There will be critical failures (called crises), but no critical successes.

I also have one over-riding requirements for the system's dice mechanic: one roll per player per task resolution. This means that if you have two people in a conflict, both players get one roll and from this roll, you should determine:

* Initiative, if the situation requires initiative.

* Winner of the conflict

* Degree of success and failure

* Amount of damage dealt, if the situation requires a damage result

If you need additional information about the system, please ask. I'll be glad to provide more information. I'm just trying to keep the information relevant to the dice mechanic and feel like I've already inundated you with information.

So, now my challenge: I recently had the revelation that the dice should be a modifier to the skill+specialty. You see, I was originally going to use a single d20. I liked the simplicity of it: roll once and add skill+specialty. You don't have to add multiple dice. Plus, it wouldn't be a linear scale since all rolls are opposed. With the d20, I can do the following:

* 1's are critical failures and give you 1-3 experience points depending on the severity of the crisis--which is determined by the player.

* 10's give you a Bonus roll

* 20's give you 1-3 experience points depending on whether you are successful and how successful you are.

* Your die roll for your Ability modifier also serves as your initiative.

* The amount of damage you do is determined by the number of Ups you receive.

While the die is the bulk of your total, skills and specialties still play a significant role--a higher ability score requires a lower roll on the d20 die, allowing for more chances of success. However, it still irked me that the roll could end up being the bulk of the total (and most likely would as I project that an average Ability score will be 5).

So, I started looking into ways to make the dice more of a modifer that could be a positive or negative number--after all, you don't always perform to the full extent of your ability on every total. Torg uses a system wherin you convert your d20 roll to a modifier. However, I'm not crazy about a coversion system--I want the numbers on the dice to directly relate to the modifier you add to your ability.

After much thought and more research, I came up with this idea:

   (skill+specialty)+(dx-dx) vs.(skill+specialty)+(dx-dx) or (Base Difficulty)+(dx-dx)

Players will have two dice, a red one and a green one. The red one is negative and the green one is positive. They roll the dice, compare the numbers and add the modifier to their total. Using a d6, here is an example:



-6 (red die) +6 (green die) = 0 + 5 (skill:2, spec:3) = 5
-4 (red die) +2 (green die) = -2 + 5 (skill:2, spec:3) = -1
-6 (red die) +5 (green die) = -1 + 5 (skill:2, spec:3) = 4
-1 (red die) +6 (green die) = 5 + 5 (skill:2, spec:3) = 10



(As an aside: I know that something similar to this mechanic was discussed in [URL=http://www.indie-rpgs.com/viewtopic.php?t=2695&postdays=0&postorder=asc&start=0]Mike's Standard Rant #5: The Myth of Opposed Rolls. (skill+d10 vs skill+d10 that turned into skill+d10-d10 vs skill turned into skill - 2d10 vs standard difficulty of 11). However, this seems different enough as to warrant further discussion.)

I like this mechanic because it means that your die roll isn't always going to be positive, which IMO is more indicative of reality: we don't always perform at or above our ability, which is one of my problems with the d20 mechanic. I also like the -dx+dx mechanic because sometimes your character performs exceptionally well, and sometimes he performs exceptionally poorly and his performance isn't related to how well someone else performs. (If I am not very effective at Dodging, I might actually help you hit me by jumping in front of the sword. In mechanics terms, the +dx-dx represents this by allowing for the possibility that my Ability Total may in fact be a negative score, meaning that I might give my opponent a bonus number to hit me!)

However, I do have a couple of concerns, which has brought me to my first post here at the Forge:

1) Complexity. How difficult will it be for gamers have to resolve the positive and negative dice?

2) More complexity. How easy will it be for gamers to learn that a -1 total actually results in a modifier of +1 for the opposing total?

Further, I've read on several posts that subtraction is evil--though I have not been able to find an adequate description as to why--and here I've created a system where subtraction will be as common as addition.

I'm also concerned about the range of result. I like the idea of using a d6 for this as it has a decent range of -5 through +5, but is it too limiting given the idea of using the Up Counts as I have described above? I mean, you are rarely going to exceed someone's total by 3 Up Counts--and this *should* happen rarely, but will it happen too rarely.

So, I'm looking for some helpful opinions. :) Is this mechanic too complex? Will the range of totals be too low? If subtraction is indeed evil, is this mechanic evil or is there some redeeming value? (And why is subtraction evil?)

Thanks for your help.

-Rick

Hi Rick,

Welcome to the Forge!

I think questions 1 and 2 really boil down to the same issue. There are some easy fixes for both.

In the end, anything added to one side's roll is equivalent to subtracting from the other side's roll. (Because in the end each players' total results are compared -- that is, the difference between the larger and the smaller is determined.)

So, if I roll the other guy's "red" die and he rolls mine, and instead of subtracting the other-guy's-red-die result from the other guy's score, we each add it to our own instead -- the outcome is unaffected. In other words, the results of (mods + dx - dx) vs. (mods + dx - dx) are exactly equivalent to (mods + 2dx) vs. (mods + 2dx).

The only thing that won't give you is an actual negative number to represent a subpar performance. But any player who's ever played with dice will recognize an under-seven total as subpar and over-seven as above average when rolling 2d6. (Other dice sizes will be less familiar to many, but it's easy easy to learn where the average lies.)

You could restore this quality, without subtraction or negative numbers, by keeping the two-color dice sets, letting the players roll, then swap their red dice to represent how the "negative" factors in their own performance help their opponent's cause. Do the addition after swapping the red dice. Meaningless from a pure math standpoint, but it could be a fun bit of color nonetheless. (And, as far as I know, a completely unique mechanical element.)

Subtraction isn't evil per se (which is forunate, because almost all mechanisms that have a margin of success or failure mechanism involve subtration at some point in the process). But it can introduce extra complication into the procedure, not because the operation is that much more difficult, but because of extra little bits of keeping-track that often seem to be necessary when subtraction is involved. For example, if both sides are rolling (mods + 2d6) instead of (mods + d6 - d6), they don't have to use different-color dice or remember which to subtract from which.

Here are some probability charts you might find useful:

Chance to roll the given margins on 2dx vs. 2dx (x = sides) with equal add-ons (e.g. equal skill and specialty scores):

[code]sides = 6
margin probability cum. prob. cum. prob.
(this result (this result
or better) or worse)
10 .0008 .0008 1.000
9 .0031 .0039 .9992
8 .0077 .0116 .9961
7 .0154 .0270 .9884
6 .0270 .0540 .9730
5 .0432 .0972 .9460
4 .0617 .1590 .9028
3 .0802 .2392 .8410
2 .0965 .3356 .7608
1 .1080 .4437 .6644
0 .1127 .5563 .5563
-1 .1080 .6644 .4437
-2 .0965 .7608 .3356
-3 .0802 .8410 .2392
-4 .0617 .9028 .1590
-5 .0432 .9460 .0972
-6 .0270 .9730 .0540
-7 .0154 .9884 .0270
-8 .0077 .9961 .0116
-9 .0031 .9992 .0039
-10 .0008 1.000 .0008

sides = 8
margin probability cum. prob. cum. prob.
(this result (this result
or better) or worse)
14 .0002 .0002 1.000
13 .0010 .0012 .9998
12 .0024 .0037 .9988
11 .0049 .0085 .9963
10 .0085 .0171 .9915
9 .0137 .0308 .9829
8 .0205 .0513 .9692
7 .0293 .0806 .9487
6 .0393 .1199 .9194
5 .0498 .1697 .8801
4 .0601 .2297 .8303
3 .0693 .2991 .7703
2 .0769 .3760 .7009
1 .0820 .4580 .6240
0 .0840 .5420 .5420
-1 .0820 .6240 .4580
-2 .0769 .7009 .3760
-3 .0693 .7703 .2991
-4 .0601 .8303 .2297
-5 .0498 .8801 .1697
-6 .0393 .9194 .1199
-7 .0293 .9487 .0806
-8 .0205 .9692 .0513
-9 .0137 .9829 .0308
-10 .0085 .9915 .0171
-11 .0049 .9963 .0085
-12 .0024 .9988 .0037
-13 .0010 .9998 .0012
-14 .0002 1.000 .0002

sides = 10
margin probability cum. prob. cum. prob.
(this result (this result
or better) or worse)
18 .0001 .0001 1.000
17 .0004 .0005 .9999
16 .0010 .0015 .9995
15 .0020 .0035 .9985
14 .0035 .0070 .9965
13 .0056 .0126 .9930
12 .0084 .0210 .9874
11 .0120 .0330 .9790
10 .0165 .0495 .9670
9 .0220 .0715 .9505
8 .0282 .0997 .9285
7 .0348 .1345 .9003
6 .0415 .1760 .8655
5 .0480 .2240 .8240
4 .0540 .2780 .7760
3 .0592 .3372 .7220
2 .0633 .4005 .6628
1 .0660 .4665 .5995
0 .0670 .5335 .5335
-1 .0660 .5995 .4665
-2 .0633 .6628 .4005
-3 .0592 .7220 .3372
-4 .0540 .7760 .2780
-5 .0480 .8240 .2240
-6 .0415 .8655 .1760
-7 .0348 .9003 .1345
-8 .0282 .9285 .0997
-9 .0220 .9505 .0715
-10 .0165 .9670 .0495
-11 .0120 .9790 .0330
-12 .0084 .9874 .0210
-13 .0056 .9930 .0126
-14 .0035 .9965 .0070
-15 .0020 .9985 .0035
-16 .0010 .9995 .0015
-17 .0004 .9999 .0005
-18 .0001 1.000 .0001

sides = 12
margin probability cum. prob. cum. prob.
(this result (this result
or better) or worse)
22 .0000 .0000 1.000
21 .0002 .0002 1.000
20 .0005 .0007 .9998
19 .0010 .0017 .9993
18 .0017 .0034 .9983
17 .0027 .0061 .9966
16 .0041 .0101 .9939
15 .0058 .0159 .9899
14 .0080 .0239 .9841
13 .0106 .0345 .9761
12 .0138 .0483 .9655
11 .0176 .0658 .9517
10 .0217 .0876 .9342
9 .0262 .1138 .9124
8 .0309 .1447 .8862
7 .0355 .1802 .8553
6 .0400 .2201 .8198
5 .0442 .2643 .7799
4 .0479 .3123 .7357
3 .0511 .3634 .6877
2 .0536 .4170 .6366
1 .0552 .4721 .5830
0 .0557 .5279 .5279
-1 .0552 .5830 .4721
-2 .0536 .6366 .4170
-3 .0511 .6877 .3634
-4 .0479 .7357 .3123
-5 .0442 .7799 .2643
-6 .0400 .8198 .2201
-7 .0355 .8553 .1802
-8 .0309 .8862 .1447
-9 .0262 .9124 .1138
-10 .0217 .9342 .0876
-11 .0176 .9517 .0658
-12 .0138 .9655 .0483
-13 .0106 .9761 .0345
-14 .0080 .9841 .0239
-15 .0058 .9899 .0159
-16 .0041 .9939 .0101
-17 .0027 .9966 .0061
-18 .0017 .9983 .0034
-19 .0010 .9993 .0017
-20 .0005 .9998 .0007
-21 .0002 1.000 .0002
-22 .0000 1.000 .0000[/code]

(Significant rounding error exists at the extremes of the larger-die results.)

One more thing: there are a number of issues that arise when deriving initiative from the same roll as success, damage, etc. Especially when the roll is opposed. The question is how the players know what to roll against or what skills apply to their roll if they're rolling before initiative.

One possibility is that everyone announces their intentions before the rolling. For that, the intentions have to be sort of negotiated or else you end up needing a "pre-initiative initiative" system. For instance, if A announces an intention to eat a sandwich, and then B announces an intention to attack A, A should be able to say, "whoah, wait a minute, I'll defend or counterattack against A instead of eating that sandwich." (See Sorcerer for one way this has been handled well.)

Another possibility is that everyone rolls first. This determines initiative. In initiative order, the players then decide what they're going to do. The applicable skill stats are added to the roll they already made, and the opposition does the same, depending on what the action is. This could be interesting, if you don't mind possible effects like everyone being able to pile on against someone who rolled low (whose opposition capabilities would therefore be limited), or players deciding what to do based on what their roll is good enough for. (If you're also doing the red-die-swapping thing, it would add a very interesting twist to this, though you'd have to give the red dice back after each actual resolved event.)

I'm sure you've thought about this alread, I guess this is just to say I am curious about how you plan to approach it.

- Walt

Just as a note, the system you propose is the System used in Feng Shui. Which people report great success using. The only difference is that the "ups" in Feng Shui are more or less 1:1.

Mike

Thanks for the statistical breakdown, Walt. That was very helpful. I'm gonna save that in my records. Is there a site where you can get helpful stat breakdowns explained in plain English like what you provided?

I also appreciate your analysis of the mechanic. I hadn't thought about in terms of 2d6+Ability vs 2d6+Ability. Duh. However, I am going to keep the +d6-d6 mechanic. Going to a 2d6+Ability to generate totals will still place most of the emphasis on the die roll. I know it is not statistically different from the +d6-d6, , but it is aesthetically different. Plus, the die roll would be the bulk of your total, which is exactly what I'm wanting to avoid.

Walt wrote regarding combat:

One more thing: there are a number of issues that arise when deriving initiative from the same roll as success, damage, etc. Especially when the roll is opposed. The question is how the players know what to roll against or what skills apply to their roll if they're rolling before initiative.

One possibility is that everyone announces their intentions before the rolling. For that, the intentions have to be sort of negotiated or else you end up needing a "pre-initiative initiative" system. For instance, if A announces an intention to eat a sandwich, and then B announces an intention to attack A, A should be able to say, "whoah, wait a minute, I'll defend or counterattack against A instead of eating that sandwich." (See Sorcerer for one way this has been handled well.)

Another possibility is that everyone rolls first. This determines initiative. In initiative order, the players then decide what they're going to do. The applicable skill stats are added to the roll they already made, and the opposition does the same, depending on what the action is. This could be interesting, if you don't mind possible effects like everyone being able to pile on against someone who rolled low (whose opposition capabilities would therefore be limited), or players deciding what to do based on what their roll is good enough for. (If you're also doing the red-die-swapping thing, it would add a very interesting twist to this, though you'd have to give the red dice back after each actual resolved event.)

Just as a note, the system you propose is the System used in Feng Shui. Which people report great success using. The only difference is that the "ups" in Feng Shui are more or less 1:1.

What is the mechanical effect of an "up". And it's per "full three", not "part therof"? That is, a 1 or a 2 margin doesn't get you any ups? Because if it was "or part therof" this would be 1 up, but 6 would be 2, and 8 would be 3.

Also, will you be doing exploding (open-ended) dice of any sort with this?

Mike

What is the mechanical effect of an "up".

And it's per "full three", not "part therof"? That is, a 1 or a 2 margin doesn't get you any ups? Because if it was "or part therof" this would be 1 up, but 6 would be 2, and 8 would be 3.

Also, will you be doing exploding (open-ended) dice of any sort with this?