Dice Pool Scalability

[linux]

I am designing a system and have come across a 'bug'.  My system includes 12 Attributes with corresponding skills in each attribute. My problem is two-fold. With my die pool mechanic I am running into a scalability problem. With my 2d10 dice mechanic I can't settle on a function for having an Attribute other than subdividing skills.

Die Pool Mechanic:

Each attribute has a number which corresponds to the number of die that are added to the die pool when performing a skill check.  Each corresponding skill is assigned a point value which can be added to the value of the dice to increase the number of successes in a skill check.(Note, 2 Attributes are assigned to a skill during a check. Also, tying the target number is not a success, must be greater than.) Example skill check:

 Attribute1:  3        
 Attribute2:  4            
 Skill:  5    
 Target:  5
 Total Dice to roll: 7    
 Outcome of die roll:  8,7,7,5,3,3,1

This would give me 3 successes before adding my skill bonus:
Add  1(skill bonus) to 5(die roll) for 6 (an additional success)
Add  3(skill bonus) to 3(die roll) for 6 (an additional success)

Now I have a total of 5 successes for this roll. The leftover skill bonus (1) is dropped as it can't add to any of the rolled die to afford another success.
The problem I have is with scalability. If I want to really challenge someone I have to add to the Target number(TN). The limits are obvious.  If I allow a '0', when rolled, to be rolled again and that number added to 10, then the difficulty of beating a Target of 9 and one of 10 are exactly the same to the die (ie, if I roll a 0, I automatically beat a 9 or 10)

Probabilities (and if it's wrong, please correct me) for a single die to beat these numbers with no skill bonus and a reroll on '0'

TN
13   =  7% chance of success
12   =  8%
11   =  9%
10   =  10%
9     =  10%
8     =  20%

This effect makes skill bonuses much less useful when trying to beat higher TNs.

I am requesting any clever ideas on how to bypass this or at least increase difficulty of higher TNs.
(I will make the other Dice Mechanic, a separate Topic)

[Andrew Martin]

If I want to really challenge someone I have to add to the Target Number (TN).
...
I am requesting any clever ideas on how to bypass this or at least increase difficulty of higher TNs.

My cleverest idea is this:

Realise that to challenge another player, one must engage them in the imaginary events that are happening and give the player a choice between at least two difficult alternatives, all of which matter to the player.

Simply changing target numbers and other dice tricks merely just gives success or failure. Success means the imaginary events can carry on and failure means that nothing happens. "Nothing happens" is boring and doesn't challenge anyone; all it does is increase player frustration and boredom. So increasing TNs doesn't actually increase challenge.

I hope that helps!

[Tobias]

How about doing what white wolf does (did)? For every point by which the TN goes over 10, remove 1 die that you can roll - and don't re-roll 10s.

This will also remove the 'difficulty' of having to buy a 7 roll up to a 13, say.

[btrc]

I suspect that you're not going to be able to get around having TN's higher than the result of whatever die type you use. Using d10 reduces the "dead roll" percentage, compared to a d6 system like Shadowrun (where a TN of 6 and 7 were effectively the same).

You could try working the percentages on a system where once the TN reaches 10, you alter the number of successes required instead of increasing the target number.

So, instead of needing a TN of 11 (10% chance), you maybe need an extra success, or you drop the TN and need an extra success.

Example: If I'm rolling 5 dice and my TN is 10, I need one 10. If my TN is 1 point harder, I instead need two 9's. If it is 2 points harder, I need three 9's, etc.

I like the previously mentioned idea where you simply lose 1 die for each point of TN past the die maximum.

Greg
BTRC

[Doug Ruff]

I am requesting any clever ideas on how to bypass this or at least increase difficulty of higher TNs.

Here's two options:

1) Don't allow re-rolls on a roll of 0. Instead, allow the player to spend skill points to take the die roll value above 10.

Example: Eric is climbing up an extremely difficult overhang. Fortunately, he's good at this.

Attribute 1: 4
Attribute 2: 5
Skill: 8
Target: 12

Roll (9 dice): 0,9,7,7,5,4,3,3,1

Add 3 skill to the '0' = 13 (1st success)
Add 4 skill to the '9' = 13 (2nd success)

That's all Eric can manage.

Note: this ups the difficulty for novice characters, but allows highly skilled characters to guarantee at least single success as just about anything.

2) Allow a modified roll of '0' to attract a re-roll.

Example: Julie is trying to open a masterwork lock.

Attribute 1: 3
Attribute 2: 5
Skill: 9
Difficulty: 24(!)

Roll: 0,8,8,6,3,3,2,2

The '0' is automaticaly re-rolled, gaining a '9' = 19.

Julie adds 1 skill to the '9' to make another '0'. This is rerolled to a '6'. Total roll, 10 + 10 + 6 = 26 (1 success)

8 skill points left, Julie adds 2 points to both of the '8' die. These are now '0' and attract a re-roll. The re-rolls are 1, 7.

No point in adding to the '1', this die ends as 10 + 1 = 11 (no success).

Julie adds 3 of her last 4 skill points to the re- rolled '7', generating yet another '0' and a second re-roll of this die. This comes up a '3'. With her last skill point, Julie changes this to a '4'.

Total for this die: 10 + 10 + 4 = 24 (2nd success).

This may look complicated, but works better when you actually have the dice in front of you. It also generates a far wider range of results!

Hope this helped,

Doug

[linux]

Thanks to everyones' comments. I will most likely use:

1) Don't allow re-rolls on a roll of 0. Instead, allow the player to spend skill points to take the die roll value above 10.

But I still ponder if the probability of the above is that much different from this mechanic:

You could try working the percentages on a system where once the TN reaches 10, you alter the number of successes required instead of increasing the target number.

And a rebuttal to Andrew:

Success means the imaginary events can carry on and failure means that nothing happens.

I don't plan on making failure the same as 'Nothing happens.'  When there is a failure, something alternate will happen.  Success is the PC fullfilling his desire at that moment.  Failure is where a GM would usually take over.  Thanks for your point-of-view.  You all have my respect.