2d20 RPG dice rolling

[CryAxe]

[MODERATOR: Moved discussion from this thread: https://www.fantasygrounds.com/forum...ing-extension]

Very cool.
If this were reversed, counting the number of successes against a target number for a roll under dice pool system, then it would work for Modiphius' 2d20 games.

[damned]

CryAxe what is the complete mechanic for the 2d20 roll under please?

[CryAxe]

There is a difficulty number that sets the bar for overall achievement of a goal. The difficulty numbers are determined by the GM who has guidance on setting difficulty levels according to the rulebooks. The player must roll at least as many successes as what the difficulty level is in order to triumph. The default number of d20 used are 2 and the standard difficulty is 1, but can be as high as 5. The number of d20 dice used on a roll are determined by several factors, but it often involves a give and take of meta currency between the GM and the players. They can buy extra dice for a higher chance of succeeding at the task, but by doing so they give the GM a resource (depending on the game, called Doom/Heat etc.) that is used to either up the difficulty to the players sometime afterwards in some way or at least make things more interesting for them. The upper limit of dice is 5, although up to three players may contribute one die each to help with the roll at the expense of their own actions and these dice don't count against the 5 dice limit because it isn't the roller's dice that are increasing the number over the 5 dice limit.

Typically the target number for success on dice rolls are a character's attribute + skill. In this respect it is very similar to the typical d100 system, but as a dice pool. For each die rolled that is on or below that number it is counted as a success. Then the total number of successes are added and compared to the difficulty number.

Another method of acquiring extra dice is through Momentum. Momentum is the number of successes that exceed what is required to achieve victory. Momentum can be used during the same action to have additional effects or even greater success over the original challenge. It may also be reserved for a time, made into extra dice and put into a dice pool of limited size for use later on. One extra success equals one Momentum, which in turn may be used immediately for added effect or as one extra die for later use. The Momentum pool is a group pool that any of the players can draw from.

Still, there is another resource that players have. It is called different things in the different games, but it equates to luck or fortune. Players can acquire it from the GM through good play. It is an extra dice that automatically is a 1, as if the player rolled it and it turned up as a 1. There are hard limits for the amount of Momentum and Fortune/Luck that can be held at any given time. Also, the Momentum pool decreases by 1 at the end of every scene (a scene being a segment of the story or session that could be identified as a location or encounter that stands separate from what came before or after, like a scene of a play, show or movie).

There are two types of skill advancement in the 2d20 system. There are Expertise. They raise a character's total Skill amount and are used to determine chance of success on rolls. Then there is Focus. They further the advancement of Skills where the character has focused and create the possibility of multiple successes per die. They make the lower numbers of the die count as an extra success. As an example, a player may need to roll for driving a vehicle through dangerous environments. They may be required to use their Coordination Attribute (10) + their Driving Skill (2). Perhaps the character has some Focus (1) in Driving. This means that it requires 12 (10 + 2) or lower on each die for each success, but each 1 rolled is an additional success. So if two dice were rolled and one was a 10 and the other was a 1, it would equal 3 successes.

That is the primary dice mechanic used in the game.

There is a second dice mechanic that is used for determining things like damage. For instance, if an attempt to hit an enemy succeeds using the mechanic explained above, then the secondary mechanic is used to determine damage. This mechanic is more akin to that of Mutant Year Zero. A number of d6 are rolled. The number is often determined by the form of attack or the weapon used. Some of the numbers, or sides of each d6, equal one or two damage to a foe, some numbers are ignored and others equal one damage plus an effect. The effect would be related to what was used for the attack. As an example, a whip might grapple an opponent as well as cause damage or a club might knock someone prone along with causing damage to the target.

This system was co-created by Jay Little, the same co-creator of FFG Star Wars. One of the main differences that I see between the two game systems is that in FFG Star Wars random dice rolls determine multiple effects at the specific time the dice are rolled and in 2d20 the use of tokens as a meta-currency is used by the GM and players for how and when they want to cause effects. One is more random and improvisational, the other more deliberate and tactical.

[CryAxe]

Personally, I do a bit of house ruling with the dice. Same mechanic, but different types and numbers of dice. So if anyone makes a dice extension for 2d20, leaving it open for some options in that regard would be very nice.

[damned]

Thank you for the detailed response CryAxe.
[Trenloe please feel free to split this off into another thread if required]
How many Attributes and Skills do players have and what do they range from in scores?

[CryAxe]

In Infinity and Conan there are 7 Attributes, Mutant Chronicles has 8. For Conan and Infinity they are Agility, Awareness, Brawn, Coordination, Intelligence, Personality and Willpower. Mutant Chronicles doesn't have Willpower and Brawn but instead uses Strength, Mental Strength and Physique.

Humans have attributes ranging from 6-12 in the system, with 8 being the Human average. Each skill falls under one of the Attributes. There are a fair number of skills in total, but it's rather easy to keep up with given that each is associated with an Attribute. Most Skill Expertise and Skill Focus have levels ranging from 1-3. However, players may have up to 3 Signature Skills with which they can raise their Skill Expertise and Skill Focus up to 5.

Each Skill has a Talent tree associated with it. Talents are specializations of certain skills. This is similar to FFG Star Wars skill trees. You must master one before learning the next and there are branches with choices along the way.

[damned]

Building any sort of automation into that is a much bigger task...

First you are generating how many dice to throw, collecting the attribute and skill to determine the initial target number and then throwing the dice and counting those that are under the target, and then comparing the number of those successes with the overall success count target....

How would you visualise this in FG?

A human mind can do all this very quickly but building an interface that does this with automation is going to be cumbersome I think.

[CryAxe]

First, it would be useful to simply have a variant of the extension described in this thread. One that recognized roll-under outcomes.

The rest would be a larger effort of course, but I imagine that it would be similar to the creation of Bennies in SW or Fate Points in Fate.

Considering that Modiphius is using this system for all of their first party games, aside from Achtung Cthulhu which currently uses CoC rules, I believe that 2d20 would be a a platform that receives wide spread use on FG.
The games that already use 2d20 or have been announced for 2d20 are:
Mutant Chronicles
Infinity
Conan
John Carter of Mars
Star Trek
and they've stated that there are more games on the horizon yet to be announced.

[damned]

Hi CryAxe - Ill add the extension into MoreCore to count Roll Unders but it is still a massive leap away from you are describing in post #11.

Im going to ask the question again because it might bring us closer to an understanding - How would you visualise this in FG?