I was thinking how a roll under system could handle opposed actions when I thought of this, it's probably been done, but it needs some work I think - i've not read anything else that uses this system so I don't know.

Essentially one person makes his roll, while the opposing character then responds. If he succeeds the ball is then passed back to the original to carry on until a decisive victory is scored: this happens if the opponent cannot or does not succeed or continue. If that opponent not only succeeds his roll but rolls no greater than the other person's result then he himself scores that decisive victory.

So, for example, person a is sneaking through an area laden with security cameras; he's trying to breach a secret base. He makes a Sneak roll and succeeds, not triggering alarms therefore. However the base security operator responds with his Camera Operation roll to see if he spots the sneak. If his roll succeeds that means the sneak hasn't been detected, but hasn't made it through (somehow). If his roll not only succeeds, but beats the sneak's result then he immediately sees him and the sneak is discovered. If he fails the roll, the sneak gets past. This assumes an active opponent; if there isn't one then simply succeeding his sneak roll is enough to get through.

This would also have to work for combat

I don't understand the idea that roll under mechanics are somehow unable to do opposing rolls. There are three main methods - which chance of success roll is lowest, which chance of success roll is highest without going over, and which quality of success roll, if separate, roll is best - which all work fine without needing extra rolls. Extra rolls should only be used in the case of a tie, exactly as in roll over opposing rolls.

-clash

Yeah, I don't get the problem either. It's perfectly possible to compare dice results in a roll-under system. I usually compare margins of success. When subtraction math gets trickier due to larger numbers being involved, such as for example in d100 systems, I use the "blackjack method", i.e. highest roll under stat.

It's very simple in RQ/BRP/AEON. Both sides roll. Highest successful score wins, except Critical* beats Special** beats Success.

* Critical = roll equal to or less than 5% of your chance of success.

** Special = roll over 5% and equal to or less than 20% of your chance.

Quote from: flyingmice;520283I don't understand the idea that roll under mechanics are somehow unable to do opposing rolls. There are three main methods - which chance of success roll is lowest, which chance of success roll is highest without going over, and which quality of success roll, if separate, roll is best - which all work fine without needing extra rolls. Extra rolls should only be used in the case of a tie, exactly as in roll over opposing rolls.

-clash

Well the normal complaints are:
1. Subtraction is slightly harder than addition
2. Blackjack success is counter-intuitive. Higher is sometimes better and sometimes worse.

You shoulda taken me to the cleaners in my design analysis thread where I was waffling on about this !

The suggestion would indeed be to use something the new Warhammer RPGs describe as Degree of Success.

Quote from: Bloody Stupid Johnson;520690Well the normal complaints are:
1. Subtraction is slightly harder than addition
2. Blackjack success is counter-intuitive. Higher is sometimes better and sometimes worse.

Both of which are covered by the first method, which is a straight comparison - which I am sure you noticed...

Quote You shoulda taken me to the cleaners in my design analysis thread where I was waffling on about this !

You're not the first person to say this, but I hadn't yet reached my limit. This thread did it.

-clash

Quote from: flyingmice;520702Both of which are covered by the first method, which is a straight comparison - which I am sure you noticed...

Its a low-sleep week I've had a friend in from overseas and have been doing lots of late night RP sessions this week, followed by early morning cat attack (usually) and then usually work...

So yeah I did miss the first method you mentioned... my peeve with that would be that chance of winning opposed rolls seems to rise only very slowly with character skill, though ?

QuoteYou're not the first person to say this, but I hadn't yet reached my limit. This thread did it.

-clash

Ooh, mouse on the edge!

Additional thought: "use the roll, lowest wins" is also difficult to translate into concrete success terms (stuff like e.g. jumping distances or spell durations), since in most cases higher is better. Not a problem with opposed rolls, I know, but still a drawback to the system (particularly if the system tries to have a generally unified mechanic).
 
 
On the actual OP: yes that works, although I would say slightly awkwardly; the numbers in the comparison would work very much like like an additive system, except for the possibility of one of the opponents failing the roll completely. In the variant here the order of operations ("attacker" has to roll, then "defender" has to roll) leads to a "first mover disadvantage"; the first person to roll may fail, so their opponent doesn't need to roll to beat them.
 
I'd imagine this system could have entire chains of rolls where a character makes a roll by X, then the opponent rolls at -X and succeeds by Y, then the first opponent rolls again..? .I imagine it would take a particularly long time using something like 3d6 roll under (for evenly matched opponents)?

Quote from: Bloody Stupid Johnson;520781So yeah I did miss the first method you mentioned... my peeve with that would be that chance of winning opposed rolls seems to rise only very slowly with character skill, though ?


Additional thought: "use the roll, lowest wins" is also difficult to translate into concrete success terms (stuff like e.g. jumping distances or spell durations), since in most cases higher is better. Not a problem with opposed rolls, I know, but still a drawback to the system (particularly if the system tries to have a generally unified mechanic).

Yes, these are both problems with the "lowest wins" method. That's why a lot of people use the 'blackjack method' instead, though it's slightly more difficult conceptually.

-clash

Put me down as a not a fan of "blackjack success" (great handle BTW).

I prefer "lowest roll wins" because I like using the difference between skill level and dice roll result as a measure of the degree of success. And I too, feel that "lower is always better" is easier to work with.

Quote from: The Butcher;520819Put me down as a not a fan of "blackjack success" (great handle BTW).

I prefer "lowest roll wins" because I like using the difference between skill level and dice roll result as a measure of the degree of success. And I too, feel that "lower is always better" is easier to work with.

I like all three variants. Then again, I like all resolution mechanics. I just think different ones do different things better than others, and there is no one type that is better at all things.

-clash

Quote from: The Butcher;520819Put me down as a not a fan of "blackjack success" (great handle BTW).
 
I prefer "lowest roll wins" because I like using the difference between skill level and dice roll result as a measure of the degree of success. And I too, feel that "lower is always better" is easier to work with.

Hang on, I'm confused now.
Sorry, FM, by "lowest roll wins" I was assuming you meant actual roll....not the difference between the low roll and the skill score...since you said no subtraction was involved...?
 
There's actually two methods here. For example:
1. roll under with d20, opponent A has skill 10 and B has skill 18.
Say A rolls 6 and B rolls 7.
 
You could determine who wins by either
-highest margin of success, so B wins because he won by (18-7=11 points), while A only won by [10-6=4 points]. Requires subtraction.
-lowest roll wins, so A wins because 6 is less than 7. The inverse of the blackjack method. (AD&D speed factors worked, I think, something like this).
 
My bitching in the prior post was about the second version, whereas The Butcher said he liked "lowest roll wins" (I understood FM to be using the second method here, since he said there was no subtraction) and then goes on to talk about the difference in rolls (the first method) ??
 
?

Quote from: Bloody Stupid Johnson;520882Hang on, I'm confused now.
Sorry, FM, by "lowest roll wins" I was assuming you meant actual roll....not the difference between the low roll and the skill score...since you said no subtraction was involved...?
 
There's actually two methods here. For example:
1. roll under with d20, opponent A has skill 10 and B has skill 18.
Say A rolls 6 and B rolls 7.
 
You could determine who wins by either
-highest margin of success, so B wins because he won by (18-7=11 points), while A only won by [10-6=4 points]. Requires subtraction.
-lowest roll wins, so A wins because 6 is less than 7. The inverse of the blackjack method. (AD&D speed factors worked, I think, something like this).
 
My bitching in the prior post was about the second version, whereas The Butcher said he liked "lowest roll wins" (I understood FM to be using the second method here, since he said there was no subtraction) and then goes on to talk about the difference in rolls (the first method) ??
 
?

I missed the "difference in rolls" bit. I meant whoever rolled lowest wins - straight comparison, as you thought.

-clash

I really shouldn't do this...

Opposed rolls are handled this way in Age of Heroes

1. The active player is determined, i.e. the one who initiates the skill contest. Example: Character A is attempt to use stealth to pass character B unnoticed. Character A is the active player.

2. A Normal Skill roll is made using the following:

Success = 50 + Active Players Skill - Passive Players Skill


Example: Player A has a Stealth skill of 53, Player B has a Perception Skill of 67.

Player A chance of success is 50 + 53 - 67 or a 36.

Normal degress of success apply.

Single roll, one set of additions and subtractions made before the roll such that the player understands his chances.