Open Game License: P&P, the modular, free-to-all, RPG

[GMMichael]

Opposing d20 rolls:

versus Player:
Two player/characters are having a tug-of-war. Each rolls d20, adds his Fight-Unarmed skill (which includes a bonus for high Physical ability). Higher result wins the tug-of-war.

versus GM:
A character wants to leap over an iron golem. The iron golem is 15' tall. The GM decides that this task is Unlikely (+12), and rolls a d20, adding 12 to the result. The player rolls d20 and adds his Movement skill points (which include a bonus for high Physical). If the player's result exceeds the GM's result, he clears the golem.

 

[Dethklok]

Right. So what I was noticing in my first post is that

* You have a nice, sloping probability distribution, but

* Your numbers will be large, so,

* Why not use d10 vs d10 or d6 vs d6?

2d20 will not give the same 5% steps that 1d20 will give. In case you haven't seen probability distributions graphed, what you get if you roll d20 minus d20 is a triangular distribution:

+19: 1 in 400
+18: 2 in 400
+17: 3 in 400
+16: 4 in 400
...
+3: 17 in 400
+2: 18 in 400
+1: 19 in 400
+0: 20 in 400
-1: 19 in 400
-2: 18 in 400
-3: 17 in 400
...
-16: 4 in 400
-17: 3 in 400
-18: 2 in 400
-19: 1 in 400

This means that we could expect fight-unarmed scores to quite regularly exceed the 20s and often reach the 40s; in order to have a significant advantage over another person in tug-of-war, one character would need a fight-unarmed score score several points higher than the other. Now, maybe these big numbers are appealing to you, but this level of granularity goes far beyond the 5% you mentioned earlier, and enters the realm of false precision. If your game consists almost entirely of these resisted rolls, you would be well advised to drop down to d10 vs d10, or even d6 vs d6.

 

[GMMichael]

Alright, I did some math. And I think I see how each +1 to your roll gives you successively smaller odds at beating your opponent. Which is interesting, because if your opponent takes 10, your decreasing odds become exactly 5% per point. And if you take 10 as well, you have exactly 100% or 0% odds of winning.

Which means to me: this uncertainty system is incredibly complex on paper. But is it really very complex in practice? You roll your d20, add your skill points, and if you beat your opponent, you win. Sure, if both parties roll, you need several points for a significant (15%) advantage over your opponent. But that sounds about right: if one tugger has +3 or +4 Fight-Unarmed points, shouldn't the wizard with +0 in Fight-Unarmed still have a chance to win?

 

[Dethklok]

It isn't complex at all in practice, but your numbers get a little big. That's all I'm trying to get at. I don't really want to roll 7, add 36, and compare that to someone else's 18 added to 23, when I could roll 3, add 6, and compare that to someone else's 5 added to 2.

if one tugger has +3 or +4 Fight-Unarmed points, shouldn't the wizard with +0 in Fight-Unarmed still have a chance to win?

Unless you're using a resisted d4 vs. d4, the wizard will still have a chance to win. With a resisted d10 vs. d10, and the wizard having 4 points less than his opponent, the wizard would win (1 + 2 + 3 + 4 + 5)/100 = 15% of the time, they would tie 6% of the time, and the other guy would win the rest of the time (79%). In a resisted d6 vs. d6 contest, the wizard would win (1 + 2)/36 = 8.3% of the time and tie another 8.3% of the time. How you handle ties is up to you.

You may also bear in mind that d20 vs d20 gives very rare rolls of 20 vs. 1, so if you're going to allow criticals they would probably have to occur on some odd combinations like 19 and 2 or 20 and 3 or something like that. Personally, I like d6 vs. d6; for you, I'd recommend d10 vs d10.

 

[GMMichael]

Forgive me for not paying attention, but I don't see where the big numbers come from. Yes, under this system, characters -could- have to add 19 (die) and 15 (skill points) and 8 (ability bonus), but those number occur at 15th level or so. A -really high- result, between 5th and 10th levels, would be a 20 on the die, plus 8 skill points, plus 4 from an ability score. My die results should actually be lower than D&D 3.5 numbers, since the max ranks are level instead of level+3, and my system hands out much fewer skill points.

 

[Dethklok]

Most roleplaying games have power levels vary enough from one character to another that a starting character could never approach beating a mid-level character, who in turn is utterly at the mercy of a high level character. (In anything earlier than 4e D&D, those levels are something like 1, 8, and 20.)

Assuming your game can mimic this power spread, then, your d20 vs d20 mechanic requires that a "high level" character have skill levels at least 10 points higher than a "mid level" character, who must in turn have skill levels at least 10 points higher than a starting character. But the starting character is usually a specialist of his kind - a starting warrior should be better at fighting than a starting wizard, say - and thus should probably be significantly higher than zero; probably around +5. So this means that your high level characters have skills of +25, or more likely, +30 and up.

Maybe your game can't mimic this spread. But if not, then why not? It's hardly unrealistic, and it's definitely fun.

 

[GMMichael]

Assuming your game can mimic this power spread, then, your d20 vs d20 mechanic requires that a "high level" character have skill levels at least 10 points higher than a "mid level" character, who must in turn have skill levels at least 10 points higher than a starting character.

This holds true in D&D, but the point spread is a little subjective. In a different setting, say Game of Thrones (low magic, low power), I think those numbers change a bit.

But the starting character is usually a specialist of his kind - a starting warrior should be better at fighting than a starting wizard, say - and thus should probably be significantly higher than zero; probably around +5. So this means that your high level characters have skills of +25, or more likely, +30 and up.

Starting characters in my system vary, regarding this, in three ways: ability scores, skills, and perks. A starting warrior probably has a +1 to fighting from his Physical score, another +1 from his first skill point (in Fight-Melee), and a perk that increases his physical damage capacity, effectively giving him more stamina. He's also likely wearing better armor and weapon than a starting wizard.

Gear aside, that's +2 to his attacking, and probably max damage of 16.

The wizard likely has a low Physical, resulting in a -1. He won't be buying a Fight skill point. He might buy a Parry skill point, but that's not likely. His perk, if he wants to be a casting beast, will relate to metaphysical power, not fighting.

Gear aside, that's -1 to his attacking, and max damage around 8.

So the fighting difference is measurable. However, my system's level 1 is pretty chill: it's for commoners or children, really. Level 2 is a much better measure of specialization. For the high level characters (level 15), especially those who want enough generalization to be survivable, they will probably have 3 good skills (dabble in one or two more), with 7 points each, and then a bonus from ability scores between 3 to 6.

Maybe your game can't mimic this spread. But if not, then why not? It's hardly unrealistic, and it's definitely fun.

The core rules don't mimic this spread. But they can, simply by creating classes, granting more skill points per level, using perks to buy more skill points instead of perks, et cetera. The rules are supposed to encourage modification, and I hope that changing the die of the standard roll and increasing skill points a viable options for that.

 

[Dethklok]

Great! Sounds fun!

 

[GMMichael]

The mental landscape has formed.

http://www.obsidianportal.com/campaign/p-p-rpg/wikis/mental

If you're a Psionics expert, or even know a thing or two about the cyber world, please take a look.

 

[GMMichael]

The above-posted rules discuss "mental weapons," or ways to beat an opponent's mind into unconsciousness. The rules also mention that minds can be soothed just as they can be damaged.

Is this a fair use of bardic music? And psionic attacks?

Mental weapons start at d4 damage, and mental defenses start at d4 protection. Each (weapons and armor) require a perk to acquire, and characters get one perk per level.

If d4 damage is an average of 2.5, and a 1st-3rd level opponent is likely to have 10 mental health, then it would take an average of 4 mental attacks to knock an opponent out. (Unless the opponent has mental armor, Concentration defense, or a counter-bard).

Do you see any issues with this (especially before I bring actions-per-round into the picture)?