Help with a Stepped, Additive Dice Pool Mechanic (long)

[haunted]

Overview
I'm working on the Dice Mechanic for the Aspect Engine, a system that I plan to use for two settings. One will be a scifi setting (called "Terra") in which earth is being terraformed after an extinction level event; and the other will be a techno-magic setting (called "Manifest Destiny"), in which the technology level is around the 19th century and the current ruling empire is expanding its domain through military conquest.

The Aspect Engine has attributes and skills. Attributes levels will range from 0-5; and skills will range from 0-10--though there will be no defined upper limit on skill level. I'm estimating that the average skill level will be in the 2-3 range. The average Attribute level will be 1-2. Attributes will cost 2 or 3 times as much as Skills to advance. The system does have mechanics for players to assume director stance, but they do not affect rolls, so are not discussed here.

I've got a lot of the system outlined and am trying to finalize a version of the dice and resolution mechanics so that I can begin play-testing. I'm going to focus on the dice mechanic as much as possible in this post.

Goals
The Dice Mechanic for the system has haunted me over the past few weeks, and I think I'm finally onto something--a Stepped, Additive Dice Pool Mechanic--that will meet all of my goals. I post here as I want to make sure there isn't something inherently broken with the mechanic--something that I'm just missing--before committing to it. Any and all help is very much appreciated.

Before I delve into the specifics, let me review my goals for the Dice Mechanic. The Dice mechanic for the Aspect Engine should have
   [list=1][*] a distinction between the use of Attributes and Skills--they should both contribute something different to the total.

   [*] one system, one dice and resolution mechanic

   [*] the result should represent a quality of success.

   [*] no automatic successes; no automatic failures. Critical success and failure will be measured by the quality of success or failure--not through the roll of the die. (Much like Raises in Savage Worlds)

   [*] a way for characters to push themselves to increase their total

   [*] a way to represent character exhaustion

   [*] experience point gain through rolling

   [*] a way to buy effects into a total. (Effects are minor damage that hinder an opponent's ability to generate totals.)[/list:o]
The mechanic

[*] Attribute Rank determines the size of the die you roll; this is the Stepped part of the mechanic.
      

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Rank   Die Level
0 0
1 d4
2 d6
3 d8
4 d10
5 d12

   [*] Your Skill Rank determines the number of dice in your Dice Pool; Add each die and your Skill Rank to generate your total. (For example, if your Attrbute is 2 and you Skill is 1, you would roll 1d6+1).
   
   [*] The high number on each die counts as a 0. For example, 8 on d8 is zero, not 8.
   
   [*] Every five rolls represents a point of Exhaustion; each point of exhaustion reduces all future totals by 1 point. Exhaustion Points are recovered by resting.
   
   [*] Characters can add one die to their roll by Pushing themselves; they Push themselves by taking a point of Exhaustion.
   
   [*] Effects can be bought by spending points from your total and must be declared before you generate your total. (IOW, you must say that you are buying the effects before you roll.) Effects will cost x1, x2, or x3 points per level each.
   
   [*] Other modifiers, such as range, target, area, etc. will modify the total in the same way as Effects.
   
   [*] Pairs rolled on any total give the character one experience point
   
   [*] Highest total wins
   
   [*] The winner's quality of success is determiend by subtracting the loser's total from the winner's total. The higher the number the better the success. I have some ideas for things to do with this number, but have not settled on anything, yet.[/list:u]
The mechanic in action

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Jayne is negotiating with a weaponsmith to purchase a sword. Her Wits attribute is 2 and her Negotiation skill is 3. She has a dice pool of 3d6+3. She really needs the sword, so she is going to Push herself for 2 dice; This increases her dice pool to 5d6+3, but it will cost her -2 on all her totals until she is able to rest.

The Weaponsmith has a Wits of 3 and a Negotiation skill of 5. His dice pool is 5d8+5. However, he wants to make this sale quickly as he is in the middle of other work. So, he purchases 2 levels of an Unskilled effect at 9 points (Unskilled effects cost x3 per level), which, if he wins the conflict, will reduce her next total by 2 dice.

Jayne rolls her 5d6+3 and generates a 2, 6, 4, 5, 2. Her roll equals 13 (6's on a d6 are 0's); adding her skill of 3, her total is 16. She also gains one experience point for her pair of two's

The Weaponsmith rolls 5d8+5 and generates a 2, 6, 2, 2, 7. His roll equals 19; adding hs skill, his total is 24. Subtract 9 points for the cost of the 2 Unskilled effects, and his total is 15. He also gets 1 experience point from his pair of 2's.

Jayne, with the highest total, wins the contest. So subtract the Weaponsmith's total from Jayne's to get her result. 16-15 = 1. 1 is not a great result, but she does win.
Questions and Concerns
On the surface, the mechanic meets most of my goals, but I do have some concerns and some questions.
[list=1][*]It seems that the rolls for this mechanic can be modified in one of two ways: modify the bonus number; and modify the number of dice rolled. However, I'd like to keep roll modification consistent. That is, similar variables should modify the roll in the same way.

[*] How do the different modification methods affect probability? [*] Which is more severe? [/list:u]

[*] The resolution mechanic for opposed totals is easy. But how do you use this same mechanic for unopposed totals? For example, if someone were jumping across a ravine, how would you determine the number of dice to roll and the size of the die in a way that is comparable to the opposed totals.

I've thought about using a table that would rely on the GM's intuition to determine difficulty. The GM would assign a two part descriptive difficulty based on his read of the situation. The descriptive difficulty would translate into a die level and dice pool. Here's an example of the kind of table I'm thinking about:
   

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           Die        Pool
Simple       0          0
Average      d4         1 or 2
Moderate     d6         3 or 4
Difficult    d8         5 or 6
Extreme      d10        7 or 8
Tough        d12        9 or 10
Continuing the ravine example, the GM might decide that the situation is Difficult/Average for a dice pool of 2d8+2.

It's not accurate, but it keeps the dice mechanics the same and can, potentially, make things easy for the GM. Perhaps, if I better understood how adding a die or adding a bonus number affected the total, I could provide guidelines for how the GM should set the Difficulty Rating.

[*] Does having the opportunity to roll only 1 die (a skill at 1 level) create an imbalance? That is, most of the time players are rolling on a bell curve, any time you roll only one die, you're making a linear total.

[*] Should I be concerned about the range of result between someone with a high skill/attribute combo and someone with a low skill/attribute combo? Personally, I like this effect--it gives multiple ability levels that generate different results. That is, I can have a high Attribute/low skill, low attribute/high skill, or low attribute/low skill. And it makes for interesting interactions between characters of different ability.

[*] Is there a calculattion I can use to determine the probability for rolling different totals given the differently sized dice pools and the differently sized dice that will also account for different bonus numbers?

[*] How many bonus dice and numbers can be added into a total before the system starts to break down? What if someone gets a chance to roll 12d12? Does this break the system or does it mean that the system allows for uber-powerful characters?

[*] How do I calculate the probability for rolling Pairs with different pools and differently sided dice? Is the idea of using Pairs to award experience points a good one or will it favor one type of die/pool combo over another?[/list:o]
I've tried to include everything that would be relevant to the Dice Mechanic discussion. If there is some information that you need and is not listed here, let me know and I'll fill in the gap. ;)

All thoughts, feedback, and help is very much appreciated.

Thanks,
Rick Cecil

[Ben O'Neal]

How do the different modification methods affect probability?
Which is more severe?

i'm no expert, and i don't profess to fully understand your mechanic, but i reckon more dice is more severe than a bonus number. if you consider one character with a roll of 1d6+3, then their minimum roll is 4, and their maximum roll is 8 (because 6=0 in you mechanic). but if you replaced that with 2d6, then the minimum is 2, but the maximum is 10. depends on what you want really.

Does having the opportunity to roll only 1 die (a skill at 1 level) create an imbalance? That is, most of the time players are rolling on a bell curve, any time you roll only one die, you're making a linear total.

well, lower levels are lower levels ;) but i was thinking, if you only have one die, you can't roll a pair, and thus can't gain experience points. does this matter?

How do I calculate the probability for rolling Pairs with different pools and differently sided dice? Is the idea of using Pairs to award experience points a good one or will it favor one type of die/pool combo over another?

been a while, can't remember. look into combinations and permutations using a recent model scientific calculator. the whole formula is only 5 keypresses if memory serves.

meh, i don't know what i'm talking about :D

[SpoDaddy]

I reccomend that you check out the Deadlands system.  It's very similar, in that attributes are ranked by die type and skill values are the number of those dice you roll in a pool.  I think you might find some solutions/answers to your questions, and some cool ideas to borrow.

[Darcy Burgess]

Before I get started, a couple of disclaimers:

1) I've never read/played Deadlands before, so unfortunately, I can't incorporate its system into my comments

2) I absolutely LOVE meaty dice mechanics in THEORY, but despise them in practice.

So, on to the comments:

This system seems really, really cool.  Overall, I like it.  (However, that's a double-edged sword, as this is a strictly theoretical discussion).

I can't help you out a whole lot with probabilities, but one thing regarding dice curves (specifically relating to experience) that I can comment on is also a good/bad thing.
- High-stat characters will earn less XP than low-stat characters (they're using bigger dice, thus reducing the odds of rolling pairs.)  This is good.  People with lots of talent don't tend to be as skillful -- thus less XP.
- Really low-skill characters (1) are going to have a really hard time earning XP -- they can't roll pairs.  Hopefully, you have another mechanic for handing out XP over and above "roll a pair".  As it stands, the system has a hole in it, but one that is easily plugged.

Also, a little fix-up that will simplify things GREATLY in task resolution.  Currently, you roll 1d per rank in skill.  You also add +1 to your total per rank in skill.  However, you've re-formatted the dice (highest number equals 0).  Chuck out the +1 per skill rank, chuck out the die-rewrite, and you end up with the same result.

In essence, your special dice work as follows:

d6 ranges from 0 to 5, but with an automatic +1 per die, it becomes a 1 thru 6.  

Thus, just make them plain old d6s, with no modifiers.

This leads to another issue: I hate adding up tons of dice at the table.  It would be nice to find a work-around for this.  Something to make resolution quicker.  You're already adding time by allowing effects to be bought.

It would be nice to see a list of your effects.

[Claymore]

Your mechanic is similar to one I designed a while ago. It works ok, with a few exceptions, the biggest being lots of adding. Some people don't like rolling up and adding 5d8 or 4d12. I found in my own playtest people had problems (although I expect it was because they just weren't used to it), adding together the different types of polys. This is the main reason I put the mechanic on the back burner. If your own players can get past it I'd say go for it.



Claymore

[haunted]

All,

Thanks for the comments and feedback

Ravien wrote:
well, lower levels are lower levels ;) but i was thinking, if you only have one die, you can't roll a pair, and thus can't gain experience points. does this matter?

Good point, Ravien. I narfed on that one. I can solve this in one of two ways:
[list=1][*]Dice Pools are Skill Rank plus one die, so even ranks of 0 get to roll one die.
[*]Come up with a different mechanic for gaining experience points through rolling.[/list:o]I'm not sure which I like, yet.

SpoDaddy wrote:
I reccomend that you check out the Deadlands system.

Thanks for the tip on Deadlands, SpoDaddy. I'd seen Pinnacle's Savage World system, but not Deadlands. I wonder if Savage Worlds ends up being a streamlined version of Deadlands...Maybe they got a lot of complaints about the number of dice. ;)

Eggo von Eggo wrote:
Also, a little fix-up that will simplify things GREATLY in task resolution. Currently, you roll 1d per rank in skill. You also add +1 to your total per rank in skill. However, you've re-formatted the dice (highest number equals 0). Chuck out the +1 per skill rank, chuck out the die-rewrite, and you end up with the same result.

That's a good point. Along these same lines, I've considered removing the addition of the skill rank to the total and have bonuses be the only thing that adds straight numbers to the total. I like this as it gives bonuses a unique function in the dice system. It also means that nothing will add dice to a total other than skill ranks, which should keep the number of the dice rolled to a minimum.

So I'm going to ditch the addition of the skill rank. I'm not quite sold on ditching the die rewrite, though. I like having the chance of rolling a 0.

On a side note, like most games, players increase their character's skills by spending experience points. Skills will advance at x2 per level--and with the projected average skill level being 3, the number of dice rolled on the average total won't be excessive. We'll see when it comes to play testing, though. :)

Eggo von Eggo wrote:
This leads to another issue: I hate adding up tons of dice at the table. It would be nice to find a work-around for this. Something to make resolution quicker. You're already adding time by allowing effects to be bought.

That's true. I hope, though, that the conflict resolution mechanic will give folks enough time to prepare their totals while the GM is resolving other players' conflicts.

Eggo von Eggo wrote:
It would be nice to see a list of your effects.

I intend to discuss these after I post about the conflict resolution mechanic.

Claymore
Your mechanic is similar to one I designed a while ago. It works ok, with a few exceptions, the biggest being lots of adding.

The amount of rolling concerns me, too. I actually prefer rolling a lot of dice--and I've gotten pretty good at adding things quickly, so it doesn't bother me personally. But, I've seen a lot of caveats about the amount of addition in additive pool mechanics, but I think I'm going to give it a shot. Besides, the developing this system is primarily for my entertainment. ;)

What other problems with the mechanic did you encounter?

Thanks for the help, guys.

-Rick

[Claymore]

What other problems with the mechanic did you encounter?

Thanks for the help, guys.

-Rick

I was trying to work in an open-ended mechanic. I had trouble finding an elegant way of doing it (simply saying you open end on the highest result doesn't work as your chances of doing so will lessen with greater ability). This might not be a concern for you.


Claymore

[SpoDaddy]

Thanks for the tip on Deadlands, SpoDaddy. I'd seen Pinnacle's Savage World system, but not Deadlands. I wonder if Savage Worlds ends up being a streamlined version of Deadlands...Maybe they got a lot of complaints about the number of dice. ;)

That's pretty much exactly how it is.  Instead of skills dictating how many of your attribute dice you roll (deadlands), your skills are ranked as die types as well.  When rolling your skill you roll the skill die, when rolling an attribute you roll the attribute die.  The PC's are "wild cards", characters fated to be important, so they get to roll a D6 along with every roll.  I don't like the lack of a correlation between skills and attributes (The only way they relate at all is that it costs double xp to raise a skill die beyond that value of it's related attribute die), but I've house ruled away that problem by simply replacing the wild card D6 with the attribute die on skill rolls.  Savage Worlds was designed to handle large battles quickly, which is why it's basically Deadlands with far fewer dice.  Deadlands is a fantastic game for combat, but combat in Deadlands while satisfying takes a while to resolve.  In Savage Worlds you can run a full 30 participant battle in under 2 hours easily, that's almost unheard of in other systems (without the GM fudging die rolls at least).  The knock on Savage Worlds is that it's too similar to a miniatures game for some roleplaying gamer's tastes (the system actually does resemble a miniatures game based on Deadlands called The Great Rail Wars).  In my experience Savage Worlds is lots of fun, but I like combat and am of the philosophy that good GM's make for good stories, the most detailed ruleset will come off as bland in the hands of a bad GM and vice versa.  Savage Worlds is the system I use to test out my settings before giving them their own system, but that said the Deadlands system will always be my favorite.  It's crunchy, but extremely satisfying and the most fun system to use that I've ever seen.  If you have any other questions about it let me know.

Claymore made some good points I'd like to address.  The addition of dice can get really monotonous (the major flaw with West End's D6 system), I suggest you only count the highest die roll instead of adding dice together.  As for the exploding dice happening more often for less talented people, I had that worry myself when designing a die step system.  I worked out the probabilities, and discovered that the more frequent explosions on the smaller dice are balanced out by the fact that the value of the explosions are less.  For example, you have a 1 in 16 chance of rolling an 8 on an exploding D4.  You have a 1 in 8 chance of rolling an 8 on an exploding D8.  There are small nuances, like a 1 in 7.something chance on an exploding D6 (better odds by an insignificant margin than an exploding D8), but these are so small and inconsequential in practice that they don't hamper anything really.  In that same example, for instance, the D8 that has a 1 in 8 chance of rolling an 8 won't just roll an 8.  On 8 it will explode and most likely end up as a 12 or 13.

[Kryyst]

Overall I think it's a workable mechanic and draws some similarities to games like Deadlands, Mechanical Dream, and Earthdawn.  So I think in essence it should work fine.

One big problem though I see is that of pushing.  For players it's a fine system and creates a cost/benefit sub component that can create drama and tension.  However I'm not so sure I'd use it for NPC's also as in the case with your Weaponsmith.  For the most part NPC's have not extended in game effect if they push their abilities.  So in this case the NPC has nothing really to loose on this transaction because once the characters are done with her they move on story continues and she's out of the picture.  In combat it's a little different, but still not much.  As even then most NPCs' will only be around for a few rounds so long lasting consequences have little effect.

Another drawback is that it just makes more work for the GM especially in combat since that's just one more factor that he's got to take care of.  It can also lead to a player feeling cheated.  The reason I say that is because the GM can basically just push any roll he wants any time he wants with little to worry about.  Where as the player has to cautiously push rolls so that he's not to worn out later on.  The GM never really suffers from that problem.

One way of addressing the issue which still gives the GM some fun is a Threat Rating style of system.  Where by you have a standard NPC of X skill and Race.  Then if you want to make it tougher just increase the Threat rating of it.  What the Threat Rating is, is a number of extra dice that it always uses on a roll.  So a TR of 1 - 3 is significant 3-5 is insane and 5+ is ridiculous.

[haunted]

However I'm not so sure I'd use it for NPC's...

I would allow some NPCs the ability to push, but not all. Recurring NPCs will definitely have the ability to push. The thug in the alleyway, or the weaponsmith will not.

One way of addressing the issue which still gives the GM some fun is a Threat Rating style of system. Where by you have a standard NPC of X skill and Race. Then if you want to make it tougher just increase the Threat rating of it. What the Threat Rating is, is a number of extra dice that it always uses on a roll. So a TR of 1 - 3 is significant 3-5 is insane and 5+ is ridiculous.

Very interesting idea. I'll have to keep that in mind as I move forward.

Thanks,
Rick

[haunted]

Want to thank everyone who chimed in on this discussion. It's been very helpful, and has, in fact, led me to set aside the mechanic for my Aspect Engine. I really like this mechanic and am planning to get Deadlands so I can see it in action, but it's too crunchy for this system. I need a mechanic that's fast, which means as little addition as possible. So, I've gone back to something that I had designed a few days ago, which is similar to TROS's skill checks.

New Dice Mechanic

[*]Attributes will represent the number of dice in your pool; the average Attribute will be 4.

[*]You must roll below your skill level in order to succeed. Skill level will average 4.

[*]The number of successes will represent the quality of success. In opposed conflict, the highest number of successes wins the result. The result is the difference between the winner's total successes and the losers total successes. I have some ideas for things to do with this number, but have not settled on anything, yet.

[*]I'm still working out a system where character's can push their total. Currently, I'm toying with this, thought it still feels a bit crunchy (I might end up killing this sacred cow. :-( )
   

[*]Every 5 rolls represents a point of Exhaustion
   [*]The first point of Exhaustion removes 1 point from the highest die rolled; The second point of Exhaustion removes one point from the second highest die rolled; etc.
   [*]Characters push themselves by taking 1 point of Exhaustion.[/list:u]
[*]Effects will be bought into the total with experience points, not result points. After you pay for effect (or set of effects) for three times, that effect (or set of Effects) becomes a Feat that you no longer have to purchase. I'll go into more detail here when I post my conflict resolution mechanic.[/list:u]
Anyway, thanks again for everyone's help.

-Rick