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Using the opposed skill rolls method in combat


KPhan2121

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I was thinking, why don't we use the opposed skill rolls rule for combat? For those who don't know, the opposed skill rolls is that the two opposing characters roll for the skill, they have to roll under their skill rating but over the opposing character's roll as well. We apply that to attack, parry and dodge skills. Would that make combat way to swingy? Like a character with 80% melee skill could get downed by a 40% pretty easily if their luck was bad enough. What do you guys think?

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You could do it, but there's no need as you already have the success matrix for determination of these things. For example, a Special Success beats a Standard Success etc.

 

If that was not already a feature of the game mechanics, then simply opposed rolls would suffice (although I would consider the best roll to be the lowest score as it is the closer value to the Critical 01. Others would prefer your method however).

 

But as the current success matrix rules exist then I would just go with that myself

" Sure it's fun, but it is also well known that a D20 roll and an AC is no match against a hefty swing of a D100% and a D20 Hit Location Table!"

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An advantage to going with opposed rolls over what is there now is that you could combine attack and defense into a single roll. Each engagement is a flurry of attack and defense by both combatants. High roll under skill wins and is able to roll damage (landed a solid blow during the exchange); under skill but second does not get to damage, but they did get their parry in and may subtract its AP, HP, whatever to reduce the damage.

 

Each combatant gets to initiate an exchange on their DEX. 

 

As this introduces the potential for damage to either combatant with each exchange, it has the potential to speed up combat noticeably.

 

You are essentially playing a different game at this point though, at least from the combat standpoint.

 

SDLeary

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I believe what you are describing is how things work in the mongoose products, such as Legend. I don't recall them even having a success matrix.

 

 

No, RQ6 and Legend use a level of success comparison. We call it a differential roll, because you're comparing the different outcomes, but it's not an opposed roll (which is roll under but high).

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A character with a 40% skill can still take down an 80% fighter if he rolls a special success. In fact, using opposed rolls would give the high skill combatant an even greater edge, as he is more likely to make the "higher but under his skill" roll that allows him to deal damage.

 

With the current ruleset, even if both combatants are very competent at parrying a hit is scored on average every three rounds (one hit in five is a special, and you make six rolls in three rounds) so there is no desperate need to change the rules to make hits happen more often.

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A character with a 40% skill can still take down an 80% fighter if he rolls a special success. In fact, using opposed rolls would give the high skill combatant an even greater edge, as he is more likely to make the "higher but under his skill" roll that allows him to deal damage.

 

With the current ruleset, even if both combatants are very competent at parrying a hit is scored on average every three rounds (one hit in five is a special, and you make six rolls in three rounds) so there is no desperate need to change the rules to make hits happen more often.

 

Well I tend to throw alot of weak minion-type enemies at my players and its a huge hassle to try and record their parry modifiers, I thought about this idea because you wouldn't have to keep track anything, just roll and compare.

You like Fading Suns? Well, I made a thing that's kinda like it!

 

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Well I tend to throw alot of weak minion-type enemies at my players and its a huge hassle to try and record their parry modifiers, I thought about this idea because you wouldn't have to keep track anything, just roll and compare.

I would look into Legend/RQ6, it sounds like their to-hit system may be what you're looking for.

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I have been using simultaneous combat in my Sword & Sorcery campaign, and I've leaned heavily on BRP's combat mechanics to help me hammer out how I've gone about it.

 

So far it has worked well for the flurry of slaughter which I've always appreciated in BRP, just speeding things up a titch...

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After playing Pendragon for a long time, we tried this recently with another BRP game we played over the Summer and it worked well. It reduces the amount of dice rolling and made combat more streamlined and did away with initiative/dex ranks altogether.

We did it pretty much full Pendragon style:

All actions declared before rolling any dice.

if you were unopposed, just make your action.

If you faced multiple opponents, you could divide your weapon skill among your opponents as desired and make opposed rolls against all you faced.

I enjoyed that there was less dice rolling in general and I am strongly considering doing it for a Magic World game that we are about to start.

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  • 2 years later...
On 10/26/2014 at 7:53 AM, RosenMcStern said:

A character with a 40% skill can still take down an 80% fighter if he rolls a special success. In fact, using opposed rolls would give the high skill combatant an even greater edge, as he is more likely to make the "higher but under his skill" roll that allows him to deal damage.

 

With the current ruleset, even if both combatants are very competent at parrying a hit is scored on average every three rounds (one hit in five is a special, and you make six rolls in three rounds) so there is no desperate need to change the rules to make hits happen more often.

What if you eliminated the need to roll under your skill and made it a simple lowest roll wins? Since there is a difference in skill, you'd probably want the 40% guy to add a penalty to his roll of 40 (80-40=40)...The less experienced fighter could still hit and harm the more experienced fighter about 17% of the time if I'm thinking correctly. With the book system, there is a 8% chance for a successful attack against a failed parry, a 5.5% chance of a special success against a successful parry, and a 1% chance of a critical success vs a successful parry.

Actually this idea seems pretty cool. If the 2 fighters were evenly matched 40% vs 40%, it would be a 50% split either way.  Every attempted attack would have a definite result, you either hit them or they block/dodge it. No more random whiffs for supposedly trained fighters. That makes perfect sense to me.

You could allow unlimited parries per round, but each one would give you a greater and greater penalty, so the each parry reduces your odds of blocking another attack. Parries and weapon attacks could share the same skill, then choosing to dodge would be a tactical choice. You could still use the existing special attack vs special defense chart if you wanted to include the special effects. You could even do it all in one step by just seeing how much the winner of the opposed roll won by. Just throwing this out as an example, but say if you win the roll by 90% it could be the same as a critical/fumble combo, 80% a critical/fail, 70% a critical/success, 50% a critical/special, and everything else is just a standard success/failure.

I like this. I'm going to have to think more about this...

Edited by Baconjurer
Added some maths
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11 hours ago, Baconjurer said:

What if you eliminated the need to roll under your skill and made it a simple lowest roll wins? Since there is a difference in skill, you'd probably want the 40% guy to add a penalty to his roll of 40 (80-40=40)...

This is more mathematics (subtraction, and potentially two-digit subtraction, instead of comparison) in order to obtain a similar result.

Quote

You could allow unlimited parries per round, but each one would give you a greater and greater penalty, so the each parry reduces your odds of blocking another attack.

This is the standard rule in the BGB.

 

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In the latest playtest version of Mongoose RuneQuest 1, if attacker and defender had the same level of success, the result was different depending on who had the highest roll. For instance, in case of a parry:

-If the attacker had the highest roll, parrying weapon's AP were substracted from damage.

-If the defender had the highest roll, twice parrying weapon's AP were substracted from damage.

Usually, weapons had 4 AP in MRQ1.

Too bad this was discarded in the published rules...

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14 hours ago, Baconjurer said:

What if you eliminated the need to roll under your skill and made it a simple lowest roll wins? Since there is a difference in skill, you'd probably want the 40% guy to add a penalty to his roll of 40 (80-40=40)...The less experienced fighter could still hit and harm the more experienced fighter about 17% of the time if I'm thinking correctly. With the book system, there is a 8% chance for a successful attack against a failed parry, a 5.5% chance of a special success against a successful parry, and a 1% chance of a critical success vs a successful parry.

Actually this idea seems pretty cool. If the 2 fighters were evenly matched 40% vs 40%, it would be a 50% split either way.  Every attempted attack would have a definite result, you either hit them or they block/dodge it. No more random whiffs for supposedly trained fighters. That makes perfect sense to me.

What somebody did a long time ago was to divide the skill scores by 5 (your special success chance) and then use the resistance table for the outcome. 

14 hours ago, Baconjurer said:

You could allow unlimited parries per round, but each one would give you a greater and greater penalty, so the each parry reduces your odds of blocking another attack.

That how Strombirnger worked. 

14 hours ago, Baconjurer said:

 

Parries and weapon attacks could share the same skill, then choosing to dodge would be a tactical choice. You could still use the existing special attack vs special defense chart if you wanted to include the special effects. You could even do it all in one step by just seeing how much the winner of the opposed roll won by. Just throwing this out as an example, but say if you win the roll by 90% it could be the same as a critical/fumble combo, 80% a critical/fail, 70% a critical/success, 50% a critical/special, and everything else is just a standard success/failure.

I like this. I'm going to have to think more about this...

One thing I was working on was to use the 10s digit as the "Effect" die. That is if you rolled a 73, your "effect" was 7 and that was the number that was used to determine things like damage. If you rolled over your skill, your effect die was considered to be a zero. The defender's "effect' Die canceled out the attack, so if you got a 73, but the defender rolled a 62, you only got a minor hit (1 point) past his parry. Weapons (and shields)gave a modifier to the effect.  I also used the 1s digit as the hit location roll, so I was able to work out success, damage and location with just one skill roll.  All in all, it was a very easy way to handle opposed rolls in a percentile based system.

 

I was working on a way to allow for critical hits (probably something with rolling doubles since it was easy to track, and increased with skill), and for handling skills over 100 (I had a couple of ideas but was hoping to have an epiphany and think of something really clever)

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48 minutes ago, Atgxtg said:

I was working on a way to allow for critical hits (probably something with rolling doubles since it was easy to track, and increased with skill), and for handling skills over 100 (I had a couple of ideas but was hoping to have an epiphany and think of something really clever)

In my version of this system, Criticals happen when the roll is under the tens of the chances of success.

In such a case, the "0" is read as a 10. Otherwise, it is a 0. :D

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3 hours ago, RosenMcStern said:

This is more mathematics (subtraction, and potentially two-digit subtraction, instead of comparison) in order to obtain a similar result.

I think the main advantage would be that it feels more real. As a player, you are equating the hand motion of rolling with the hand motion of attacking or parrying/dodging, and it just gives an illusion of having more input in the situation.

The second advantage would be that you don't have expert swordsman, with 80% skill, suffering a 20% chance of missing an enemy, even if they have a very low dodge and parry skill. I like a unpredictable results, but I also like them to be more realistically weighted.

I think if I really implemented this in the games, I would probably greatly simplify the BRP success-failure chart, and just make it a simple if-then. Something like

if you win by a significant amount you get a critical+special result. And for the case where defense wins by a significant amount maybe the attacker . Still thinking on this. 

51 minutes ago, Atgxtg said:

I was working on a way to allow for critical hits (probably something with rolling doubles since it was easy to track, and increased with skill), and for handling skills over 100 (I had a couple of ideas but was hoping to have an epiphany and think of something really clever)

What about if you win the opposed roll and roll a double less than your skill score, its a critical? 80% skill would critically hit on 11,22,33,44,55,66,77 and the 40% fighter would critical on 11,22,33, and 44.

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49 minutes ago, Mugen said:

In my version of this system, Criticals happen when the roll is under the tens of the chances of success.

In such a case, the "0" is read as a 10. Otherwise, it is a 0. :D

Doesn't that make a critical entirely luck, and not based on skill at all?

Chaos stalks my world, but she's a big girl and can take of herself.

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44 minutes ago, Baconjurer said:

I think the main advantage would be that it feels more real. As a player, you are equating the hand motion of rolling with the hand motion of attacking or parrying/dodging, and it just gives an illusion of having more input in the situation.

Uh, maybe. I'm not sure how much rolling dice feels like a swordfight. I just thought the "three in one" method would reduce the number of die rolls and simplify things. I also liked the fact that the damage was directly tied to how much better you did than your opponent, instead of being mostly random (the damage die).

44 minutes ago, Baconjurer said:

The second advantage would be that you don't have expert swordsman, with 80% skill, suffering a 20% chance of missing an enemy, even if they have a very low dodge and parry skill. I like a unpredictable results, but I also like them to be more realistically weighted.

That is the nice thing about opposed rolls. I was thinking of raising the starting scores quite a bit to try and get the full die range. Realistically, a person will hit an opponent over 95% of the time, unless the opponent does something about it (i.e.parry/dodge). So why not reflect that in the die rolls?

44 minutes ago, Baconjurer said:

I think if I really implemented this in the games, I would probably greatly simplify the BRP success-failure chart, and just make it a simple if-then. Something like

if you win by a significant amount you get a critical+special result.

That's exactly what I was trying to do with it. Basically, the damage you do is tied to the difference in effect dice (10s dice). I wasa also thinking that things like disarms, trips, force backs, beats, binds,  and such could have a "cost" in EFFECT. So you'd basically buy your specials.

 

44 minutes ago, Baconjurer said:

And for the case where defense wins by a significant amount maybe the attacker . Still thinking on this. 

Well the obvious choice would be to allow the defender to make a riposte, but I was thinking that this might work better without alternating attacks and defenses and instead just use one "fighting" roll with the winner inflicting damage on the loser . It's simplier and seems to be more realistic.In a real fight you don't just take turns attacking each other.  

44 minutes ago, Baconjurer said:

What about if you win the opposed roll and roll a double less than your skill score, its a critical? 80% skill would critically hit on 11,22,33,44,55,66,77 and the 40% fighter would critical on 11,22,33, and 44.

Yes and no. I didn't want to have "crticals" per say, but did want to tie how well someone did to how much effect they generated. The idea was that if you beat someone by a point of two you got a minor victory, while if you beat then by 8 or 9 you probably took them out of the fight. Rolling doubles would have to have a nice bonus to work, since something like a 11 would'n beat all that hot.

 

Oh, and I wanted to use the EFFECT to handle stuff outside of combat too. For instance something like a race could be handled by having to accumulate a certain number of EFFECT points before the opposition does. Same with spellcasting. For something like piloting a vehicle, each of the maneuver you want to pull off could have a cost in terms of effect points (although I had a idea of letting someone "go into the red" for a round urn while attempt a maneuver but they had to come up with the remainder next round or else they'd lose control of their craft)..

Chaos stalks my world, but she's a big girl and can take of herself.

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Personally I'm against anything that slows down combat. I want it cinematic and I want it quick. Doing a "price is right" style comparison would slow down combat for little benefit. It's simply a more granular "success matrix" that fluctuates based on skill values. Doing any sort of "effect" or comparison on the tens digit, or reducing each other's skill percent likewise slows things down.

 

If my players complain about things like this, I remind them it is merely an abstraction. This is not meant to be a combat simulator or a video game. It's a quick and easy way to drive the narrative. Once you remind them to enjoy the ride and not try to game the system, the ruffled feathers usually subside.

 

If you strive for realism or "fairer" mechanics with dice you'll end up with a system like D&D 3.5 - so rules top-heavy they have to put a rollover warning under the front cover. Remind your players to push the system to the back and bring the roleplay to the forefront. It's one of the things D100 is great at - enough framework to cover most situations, but abstract enough to stay out of the way of your story.

Edited by Robsbot
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1 hour ago, Robsbot said:

Personally I'm against anything that slows down combat. I want it cinematic and I want it quick. Doing a "price is right" style comparison would slow down combat for little benefit. It's simply a more granular "success matrix" that fluctuates based on skill values. Doing any sort of "effect" or comparison on the tens digit, or reducing each other's skill percent likewise slows things down.

I find it actually works out faster than rolling an attack, a parry, comparing success levels, then rolling damage and hit location. 

 

Chaos stalks my world, but she's a big girl and can take of herself.

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1 hour ago, Robsbot said:

Personally I'm against anything that slows down combat. I want it cinematic and I want it quick. Doing a "price is right" style comparison would slow down combat for little benefit. It's simply a more granular "success matrix" that fluctuates based on skill values. Doing any sort of "effect" or comparison on the tens digit, or reducing each other's skill percent likewise slows things down.

I don't see it slowing things down much, if at all. It's either roll vs a constant value or roll vs the other roll, still involves the same amount of effort. Might even be faster if you combine it with another roll like weapon damage. Plus get the advantage of hitting at a more realistic rate of connect. By the standard rules, even an expert fighter with 80% skills still misses their attack 1 out of 5 rounds, even when their opponent doesn't dodge or parry. Opposed rolls means attacks would only miss if they were parried or dodged.

6 hours ago, Atgxtg said:

Yes and no. I didn't want to have "crticals" per say, but did want to tie how well someone did to how much effect they generated. The idea was that if you beat someone by a point of two you got a minor victory, while if you beat then by 8 or 9 you probably took them out of the fight. Rolling doubles would have to have a nice bonus to work, since something like a 11 would'n beat all that hot.

Its an interesting idea to tie the damage done to how effectively you hit the opponent and it makes perfect sense. It might be a bit tricky mathematically to preserve the existing damage ranges without a complete rewrite of the rules. My off-the-cuff idea would be to look at the maximum possible damage they can do, and divide it down depending on how much off a difference there was in the attack vs. the defense. 

If you don't mind less variability in damage results you could do:

won by more than 100 = critical result to body location determined by the 1's dice

50 < won by < 100 = MAX damage

0 < won by < 50 = half MAX damage 

This creates a nice weighted result where you're most likely to do less damage, unless you're much more skillful than your opponent. The more your skill surpasses your enemy, the more likely you are to do more damage. The range I chose here makes it impossible for two evenly matched combatants to score a critical. 

The math isn't too difficult. It's not too bad to see if the difference between two numbers is more or less than 50 at a glance. It's also not too bad to divide and round a number by 2 at a glance. It also saves you a dice roll, and makes damage weighted rather than linear, which is what I personally prefer. 

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19 hours ago, Atgxtg said:

Doesn't that make a critical entirely luck, and not based on skill at all?

Maybe I was not clear : what I meant is if you have 4X% chance of success, you have a critical if you roll under 04.

So, yes, 10% of your successes are criticals if your chances of success are under 100%. But they keep increasing if you go past 100%, and, for instance, they will represent 15% of those if your chances are between 150 and 159.

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12 hours ago, Baconjurer said:

Its an interesting idea to tie the damage done to how effectively you hit the opponent and it makes perfect sense. It might be a bit tricky mathematically to preserve the existing damage ranges without a complete rewrite of the rules.

Well, you could simply add a die, or a static bonus, to the tens of the roll, based what you consider an "average fighter" in the original game.

Say, for instance, you consider that average guy to have a 60% skill, a d4 bonus to damage and a broadsword (d8+1 dmg), for an average 8 damage per strike.

On average, the value of the 10s die of a d100 roll under 60 will be 2.5.

Which means I'll'have to add 5 or 6 to the 10s die to get the same similar damage, or... a d8+1 for more randomness (I was quite lucky in choosing 60%, I admit...).

Edit : yes, damage output can go up to 2 point over what my average guy can do in BRP, but that's counterbalanced by the fact Atgxtg's system doesn't have crits.

Edited by Mugen
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On 4/1/2017 at 6:23 AM, Mugen said:

Maybe I was not clear : what I meant is if you have 4X% chance of success, you have a critical if you roll under 04.

So, yes, 10% of your successes are criticals if your chances of success are under 100%. But they keep increasing if you go past 100%, and, for instance, they will represent 15% of those if your chances are between 150 and 159.

Okay, that clears thing up. It's not that bad a method (in fact it's what old Strombringer used to do, pretty much). Mathematically it's not much different that doubles-at least until you break 100%. 

BTW, What if you chance of success is less than 10%? Do you have no chance of a critical, or is then a minimum of 1%

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