PDA

View Full Version : PEACH this homebrew dice pool system



Harwel
07-11-2009, 07:12 PM
This game mechanic may exist somewhere, but if it does, I haven't seen it, so forgive me if this out there already.

I was looking for information on dice probability and stumbled across this article, which gave an interesting probability curve that I liked:

http://www.edcollins.com/backgammon/diceprob.htm

This got me thinking (dangerous I know) about how to make a dice pool mechanic around this curve, with inspiration from ORE, Burning Wheel, and D6 System. ORE is pretty cool, but I have an issue with the realism of "he who hits hardest always hits first", among other things. So here are my initial thoughts.

The dice rolled are d6. A 6 is a success. You only need to roll a single 6 to succeed at a task (exception below for extremely difficult tasks). This means the more dice you add, the closer your odds of success get to 100%, but you could add essentially infinite dice to your pool and never hit 100%. Contrast this with ORE where 11+ dice guarantees success and dice pools are hard-capped at 10, which somewhat limits character progression.

One of the dice rolled should be a different color or size. This is a "wild die". If it comes up 6, it may be rerolled and the result added to the existing results. It may "explode" multiple times.

An average attribute + skill dice pool for "Joe on the street, with a competent skill level" is 4d6, which gives a 51.77% chance of success at an average task that provides some challenge. 10d6 would indicate a trained and talented individual (chance of success is just over 81%).

Difficulty modifiers add or subtract dice to your pool rather than adding additional required successes. You can't go less than 1 die in your pool, so if something would bring you below 1 die, you will need an additional 6 to succeed. For example, Joe Average has a dice pool of 4 for an Agility + Athletics roll. He is trying to walk a narrow building ledge and it's very windy. The GM assigns a penalty of -4 dice. This would take him below 1d6, so he rolls 1d6, but need to roll two sixes (remember that one of your dice is wild and can explode). This would give him a 1/36 chance of success. Good luck Joe! If it was a -5d penalty, he would actually need three sixes, and he would probably be taking a swan dive. Thus, just as nothing is 100% assured, nothing is impossible, but chances of success can go well below 1% or above 99%.

Now here is where I steal a bit from ORE. We've established that your number of 6's indicate how well you did. Your number of 5's indicate the speed with which you did it. This won't always be important, but it provides initiative in combat among other things (the rolls with the most 5's go first). One of the things that I immediately disliked about ORE is that the width of your hit was both damage and initiative. It's possible to hit fast but not hard; in fact a harder hit may be more likely to land later since there may be a larger windup (haymaker!) or longer aim involved. ORE doesn't account for that. This would.

If you want even more detail, you could use the number of 4's for something as well (such as finesse, which you could use to shift hit locations, for example).

One could take multiple actions in combat by splitting their dice pool. For example, a master swordsman with an Agility of 6 and a Sword skill of 7 has 13d to play with. He could use this one attack that will likely hit hard, hit quickly, and be very accurate. Or, he could make two attacks, one with 7d and 6d, but they are unlikely to be as well placed and would likely happen later in the round. He could also do 3 attacks, one at 7d for the bigger bad guy and two additional attacks at 3d each for his two mooks.

A character can take a defensive action in combat, again an Attribute + Skill pool. Each 6 they roll negates one of the attacker's sixes. This allows for partial parries, and "rolling with punches" and "grazing bullets" (partial dodge). Again, your dice pool can be split to defend against multiple attacks. This mechanic also provides the model for any skill contest, such as Stealth vs Perception. Ties go to the defender (or perception) since they would reduce the "aggressor" to 0 successes.

This is obviously still a rough idea, but I like the probability curves and various success levels, and it can make for interesting combat mechanics and options. It also seems like it would be fast, especially for combat since initiative, to-hit, and damage are resolved in a single roll. The "one roll to tell you everything" aspect could make it nice for online and pbp games where making a ton of rolls can slow things down a lot.

It doesn't seem like it should break at high skill or attribute levels. If you want car-chucking supers, sure, you may have 25d Strength, but lifting two tons is -20d. No normal human could reasonably do it barring those massive "OMG my baby is trapped under the car, LIFT" adrenaline rushes that you read about once in a blue moon, reflected by rolling a highly unlikely string of sixes. But your 25d Strength super (or giant or whatever) has a pretty good shot at it. (The numbers are arbitrary, but you get the idea.) Your 25d super also has nearly 100% chance of passing an average strength check and would just get a pass on most of them. The biggest drawback is that, at "Supers" levels of play, a large number of dice (or a die rolling program) would end up being necessary. A normal human is pretty unlikely to have any dice pool above above, say 15d (which gives about a 93.5% chance of success at a typical challenging activity), and this would represent a very heroic level of skill plus innate talent. A starting character would probably have attribute and skill caps around 5-6 (which conveniently makes for pretty easy Unisystem conversion).

I have no idea if I'll ever actually play this or flesh it out further, but it sounds good on paper. Thoughts are welcome, and people can of course steal whatever ideas they want.

trechriron
07-12-2009, 05:25 PM
I really like this. Its very nifty indeed. Actually it is well thought out and I want to use it now in a game! I like how the more skilled you are the better chance you have of going first AND hitting well.

It would be nifty to see damage factored into this. Maybe you can take all the 4's as a multiplier to your "damage factor"? Or you can sacrifice a number of 6's and 5's for multiplier to your "damage factor"? Damage factor being something based on your stats and something based on the weapon used. I like systems that build tactical choices in for the player without the need for special feats and abilities. I also think a resolution method with some "crunchiness" up front could help eliminate more complex rules in the actual "engine".

Not sure if I like the "unlimited" dice pool thing. I have always appreciated caps so I can avoid the "bucket-o-dice" problem inherent in some systems like Shadowrun. Maybe there could be a way to trade in a number of dice for an automatic success? Maybe you could trade in 10 dice for super ka-maya-maya success? Maybe you could trade dice in for front-loaded effects, stunts, or maneuvers? Maybe if you're "rolled" pool is going to exceed say 10 dice, you HAVE to trade in for success or effect? Something in there that limited the amount of dice rolled would make me happier (I would house rule it if it wasn't included...).

All in all I think your on to something here!

Harwel
07-12-2009, 07:34 PM
I really like this. Its very nifty indeed. Actually it is well thought out and I want to use it now in a game! I like how the more skilled you are the better chance you have of going first AND hitting well.

It would be nifty to see damage factored into this. Maybe you can take all the 4's as a multiplier to your "damage factor"? Or you can sacrifice a number of 6's and 5's for multiplier to your "damage factor"? Damage factor being something based on your stats and something based on the weapon used. I like systems that build tactical choices in for the player without the need for special feats and abilities. I also think a resolution method with some "crunchiness" up front could help eliminate more complex rules in the actual "engine".

Not sure if I like the "unlimited" dice pool thing. I have always appreciated caps so I can avoid the "bucket-o-dice" problem inherent in some systems like Shadowrun. Maybe there could be a way to trade in a number of dice for an automatic success? Maybe you could trade in 10 dice for super ka-maya-maya success? Maybe you could trade dice in for front-loaded effects, stunts, or maneuvers? Maybe if you're "rolled" pool is going to exceed say 10 dice, you HAVE to trade in for success or effect? Something in there that limited the amount of dice rolled would make me happier (I would house rule it if it wasn't included...).

All in all I think your on to something here!

More sixes = more damage for combat rolls. Depending on how I do the damage scale, each six would be a multiple, or an add, of some kind.

The bucket of dice thing is something that concerns me a little, but anything over say 12-ish dice is probably starting to get into the "superhuman" range. The key to keeping it challenging at that point is to assess penalties, which in turn reduces the number of dice. As stated in an example, your super with 25d strength may only be rolling 5d for a strength feat to throw a car or whatever (-20d). If you're rolling a big bucket of dice, this is probably an indicator that the GM isn't providing an adequate challenge. And the GM can always "handwave" a roll.