Knowledgeable Gamers; Has This Dice Resolution Mechanic Been Used Before?

[RJBowman]

My exposure to role playing games is minimal; limited to a fee Champions sessions many years ago, and the reading of a few sourcebooks including the main Champions, GURPS, Shadowrun, and Vampire player handbooks and the original Marvel RPG book.

Champions, I think, is great in that you can create pretty much any character imaginable, but the method for determining success and hit points is, I think, terrible, and methods of doing similar things in other games seems just as bad.

So I decided that everything that can be done in a game that requires randomization should be doable in a single die-roll. It it should be doable with common 6-sided dice that you can buy everywhere. And it should be done with three dice because that is the fewest dice that will give you a decent bell-curve distribution.

So I am looking at a pack of 12 cheep dice that I picked up at a dollar store; three colors, four of each color, and I realize that I could split this up into four sets of three dice if each set has two dice of one color, and one die of another color (to be called the "invert die"), and that would be the basis for resolution of any task that uses a player ability of any kind.

So what you do is you figure out what you need to roll to get a success; a number between four and 18. More difficult tasks require a higher roll (nicely intuitive, unlike Champions' convention of lower rolls being required for greater difficulty). Three is a failure no matter what, and 18 is a success no matter what (a steal from Champions and maybe other games as well).

What, you may ask, do you do about the hit points for a successful strike if the task is a combat move or anything else that requires hit points? That is where the third odd-colored die comes in. Your hit points are the sum of the two same-colored dice, plus 6-minus-odd-colored-die (invert die). So the hit points correlate roughly to the success points but aren't always exactly the same. Have you ever been frustrated at rolling a high targeting roll, then rolling a low hit point roll? It wouldn't happen with this system. One more thing; if you roll the 18 success score, you don't invert the die, so you get to womp you enemy with the full 18 hot points.

Need something bigger than 18 hit points? Some actions will add a constant to the hit points; others will have a multiplier.

So could some knowledgeable person tell me if this system has been used before?

[Madasasteamfish]

If I remember correctly from my (limited) RPGing days Abney Park's Airship Pirates RPG used a similar mechanic in term of dice rolls in that it used bog standard 6 sided dice which were rolled to give you your 'successes' and then you rolled a number of 'handicap' dice (depending on how difficult the task was vis a vis your character's skill level and their current state) which gave you 'x' number of failures which you subtracted from your successful dice rolls to give you the overall outcome. So something similar has been done before, but your proposal sounds much easier (the one drawback to the above system is the number of dice you needed as even at low levels you could have to roll 5 or 6 dice at a time.

[Peter Brassbeard]

I had to run some stats on this roll method

difficulty	%hit	avg HP	HP dev	avg/hit
4	99.537	9.5	1.1	9.5
5	98.148	9.4	1.1	9.6
6	95.370	9.2	1.1	9.6
7	90.741	8.8	1.1	9.7
8	83.796	8.2	1.1	9.8
9	74.074	7.4	1.2	10.0
10	62.500	6.3	1.3	10.2
11	50.000	5.2	1.5	10.4
12	37.500	4.0	1.7	10.6
13	25.926	2.8	2.0	10.9
14	16.204	1.8	2.5	11.2
15	9.259	1.1	3.3	11.6
16	4.630	0.6	4.7	12.1
17	1.852	0.2	7.5	13.2
18	0.463	0.1	14.7	18.0

Portion of rolls hitting and damage/roll with difficulty, but average damage/hit rises.

(attn admin: problem in CSS for display of tables element
body, td, th, tr { ...
style.css line 73 is setting text in tables to a color close to the background brown.)

[Crescat Scientia]

I had to run some stats on this roll method

difficulty	%hit	avg HP	HP dev	avg/hit
4	99.537	9.5	1.1	9.5
5	98.148	9.4	1.1	9.6
6	95.370	9.2	1.1	9.6
7	90.741	8.8	1.1	9.7
8	83.796	8.2	1.1	9.8
9	74.074	7.4	1.2	10.0
10	62.500	6.3	1.3	10.2
11	50.000	5.2	1.5	10.4
12	37.500	4.0	1.7	10.6
13	25.926	2.8	2.0	10.9
14	16.204	1.8	2.5	11.2
15	9.259	1.1	3.3	11.6
16	4.630	0.6	4.7	12.1
17	1.852	0.2	7.5	13.2
18	0.463	0.1	14.7	18.0

Portion of rolls hitting and damage/roll with difficulty, but average damage/hit rises.

(attn admin: problem in CSS for display of tables element
body, td, th, tr { ...
style.css line 73 is setting text in tables to a color close to the background brown.)

Ahhhh, now I understand your post about the problem with the color property in the CSS tables.

Meanwhile ... I have a mathematician in the family who has extensive experience in rpgs going back to 1974 who I'm going to ask about this.

[RJBowman]

It does have the weird property that if you manage to hit anything that is very difficult to hit, you will do more damage with each hit on the average than would would on the average with an easy target. In a campaign world of fictional adventure, this might not be a problem.

I am reminded of a glitch I've read about in the rules for Call of Cthulhu, where the older (and more decrepit) your character is, the faster he runs away from monsters.

[RJBowman]

Is there software that can be used for analytics of dice rolls?

[Peter Brassbeard]

I've been rolling my own analysis software in perl, scripts specific to the situation.

[Felscor]

Sorry for bringing back a dead topic, but a couple points;

1. There is a website for dice analysis, it's called AnyDice.com
2. If you're rolling 3d6 where 1 die is 6 minus roll result, that means the invert die has a range of 0 (6-6) to 5 (6-1). Making the total die roll range between 2 and 17, not the typical 3d6's 3 to 18.

P.S. I'm also seeing a strong correspondence with GURPS here, which you have said you read; perhaps just using that system is the go?