Wednesday, June 10, 2009

d20 Rethought: New Trick Subsystem?

A recent hangup in my work on the Avatar RPG has led me to an idea for an alternate bending sub-mechanic that I may well use for all kinds of Tricks in d20 Rethought in general. The reason for this is that it winds up providing the overall system with a curious flexibility regarding which kinds of interaction a given GM/designer wants the system to focus on- combat, social interaction, magic, etc.

This advantage is enough to override my concerns about the disadvantage this subsytem would bring; namely, a loss of elegance due to it deviating from the core mechanic. How bad is this deviation, you ask? well, the mechanic's about half a step away from being a die pool. (GASP)

First, say that any Trick (i.e. any base effect) has an associated "Trick DC". Trick DCs will work on a different scale than normal DCs, because rather than making an normal check you make an unmodified, exploding* die roll that may or may not use a different kind of die. If the initial roll fails, you have a number of rerolls available equal to the number of relevant feats you've taken- "relevant" meaning they pertain to your particular skill or subskill. Once you roll high enough, you can spend the unused rerolls to upgrade your Trick's result beyond the base effect.

So let's say, hypothetically, that have a Wallrun acrobatics trick that lets me run up or along vertical surfaces for short distances. The base effect lets me move 5 feet upwards or (with a 10-foot running start) 10 feet horizontally with no decrease in my move speed. Each upgrade can be spent to make another 5 ft. of vertical or horizontal movement (limit 2), or to make a jump check perpendicular to the wall with a small penalty (no limit, but penalty on jump check stacks). Wallrun has a fairly easy Trick DC; if we assume that in this particular system Trick Dice are d10s, then the DC would probably be 4. So if I have a pool of 3 Acrobatics trick dice total, and my first roll is a success (it gets a result of 4 or higher), that leaves me with 2 "dice" to spend on upgrades, meaning I could run horizontally along a wall for a length of 20 ft. before having to drop or grab hold of something, or run 15 ft. horizontally and then jump away.

Now, how does this afford an rpg system the "curious flexibility" I was talking about earlier? Let's look at the Avatar RPG for an example. In this RPG each of the four types of "bending" (elemental control) has more feats than a single character could possibly take. At a high level, you could feasibly have 10 bending feats and thus a pool of 10 dice, letting you significantly upgrade the effectiveness of your basic moves and reliably pull of advanced moves with a Trick DC of 8 or 9. Meanwhile, the Manipulation skill probably has only a single 3-feat chain associated, providing a number of basic moves with low Trick DCs. So I can invest a small part of my character into being socially manipulative, and have as many as 4 trick dice on hand when using my small array of Manipulation Tricks. If a splatbook full of social interaction feats comes out, suddenly I can instead play a character who's 100% focused on becoming a master social puppeteer. At high levels this character will instead have a full 10 Trick dice on hand and a large array of Manipulation tricks.

In other words, the "power" of a given area of expertise depends on how much the character can invest in it. A single Acrobatics feat chain allows for moves on par with a real-life le parkour runner. Introduce more acrobatics feat chains and you can have a character who vaults and tumbles through the air like they're in the Matrix- but only if they invest a corresponding amount of their own ability, keeping things balanced. A GM who wants their game to focus on kung-fu action rather than politics can just advise players that the majority of the encounters in this game will be resolved with kung-fu battles and that investing too much unrelated feat chains probably won't pay off.

Though I can't yet speak for d20 Rethought, I know that in the Avatar RPG bending attacks will involve first rolling your Trick Dice and then making a normal check to attack your opponent with said effect. This approach is necessary because it's the best way to allow the attacker create an attack that's extra-effective against a given type of defense, before the target chooses whether to defend and how they'll do it.

As always, thoughts and feedback are appreciated.

*: Whenever an exploding die gets the maximum result, you reroll and add a number equal to 1 less than that result. Roll a 6 on a d6, and you reroll and add 5. The end result is that an exploding die can theoretically get any result, no matter how high, so long as you keep getting the maximum result on your die roll.

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Wednesday, June 3, 2009

Avatar RPG: Combat System Musings

Just an attempt on my part to explain several aspects of how I see the tactics of combat working in this system I'm putting together. Those of you who've been following my work on d20 Rethought will find alot of familiar material here, and as such the same will be true to a lesser degree for anyone who's familiar with the d20 system in general.

Item 1: Character position and range
I'm thinking that this rpg won't invest a great deal of effort into tracking character's locations respective to one another. A rough grid of ten-foot square, where characters that are in close combat share a single square, sounds like it ought to be workable. A long-range duel would be a little less dangerous because participants are investing some of their skill into making their attacks long-range enough to reach the enemy, rather than into making the attacks deal more damage. Meanwhile, a melee-range bending duel could be made to match the fast pace seen in the show if you make Buildup actions (see below) easy to disrupt in hand-to-hand combat and thus give characters a reason to focus on quick back-and-forth moves.

Item 2: Action Types
All characters can take one Primary, one Secondary, and one Side action per turn. You can give up a Primary Action in favor of another Secondary action, and give up a Secondary action in favor of another Side action. Some actions will be labeled as "Immediate" (i.e. "Immediate Secondary Action). This means that you can take them at any point, even if it's not your currently your turn. If you've already used up that action for the current turn, you can still take an immediate action by expending your use of that action on your *next* turn.

Action Types:
-Most attacks and/or uses of bending are a Primary action. Same goes for most combat actions that require a skill check.
-A "Buildup" check is a secondary action. This is where you make a skill check, divide the result by five (rounding down), and add that as a bonus to your subsequent primary action. Possible buildups include an Acrobatics check to swing from the chandelier prior to making a flying kick or using earthbending to lift up a particularly huge boulder before you hurl it at someone. Alot of offensive bending moves will work best if you use a buildup action first, essentially allowing you to dedicate the results of two checks towards the same single attack and thus give that attack better odds of breaking through the enemy's defense.
-A defense check is an immediate secondary action. Normally, any skill check made against you- to attack you directly, sneak by you, deceive you, whatever- will compare the opponent's d10 roll+skill+modifiers against your skill+modifiers+5 (unless I change the die mechanic, but that's a matter for another post). A defense check lets you roll too, and use that result (if better) the next time you'd use your passive defense. It can also sometimes let you use different skills to defend.

(What all this means is that during most combat rounds you'll make a single attack, but must carefully decide just when and how you'll make your move- do I use my secondary action to Buildup my own attack or Defend against my opponent's move?)

-Skill checks that can be multitasked with relatively little effort (say, making a Manipulation check to lie to someone during a fight) can be done as a Side action, but carry a -2 penalty because you're not giving the task your full attention. You can't multitask an attack, that's always a Primary action.

Note that Buildup only lets you use a check as a boost to another check. You don't get the normal benefit. So if I actually need to make an Acrobatics check before I'm close enough to my opponent to kick them, I could do the acrobatics check as a Side action (with the -2 penalty) and also spend a Secondary action to make another Acrobatics check as buildup for my attack.

Item #3: Initative
During combat, your Initiative Count- i.e. the results of your initiative check- determines who goes first. When combat starts, everyone who's aware that it was about to start gets a free initiative check; otherwise, your count starts at 0, which means you have to spend a secondary action to reroll your initiative before you can do anything else.

I'm considering two different wrinkles I could add to this process. The first is having init checks be an *immediate* secondary action, meaning that you can try to act quickly and outdo your opponent that way. Remember Toph's first "fight" in the series? Against The Boulder?

Yeah, kinda like that.

The second wrinkle is to allow various things to modify someone's iniative count. Used as a cost for a bending technique, this would give me some nice leeway- and I'd definitely have it apply to anyone who gets a solid hit scored on them in combat, forcing them to "get their bearings" again (i.e. reroll initiative) before they can get back in the fight.

Item #4: Bending Faliures
Remember the time Toph tried to make a huge dirt cloud with Earthbending, then flubbed it and had to try again? No, because if someone screws up a bending attempt in Avatar it's either due to outside interference like being punched in the face, unexpected issues such as a solar eclipse, or them being an utter beginner. So what happens when you roll poorly on a bending check?

One of two things. Option A is to accept the poor result, which usually just means a relatively small-scale bending move. Option B is that the move takes longer. You take a Secondary action to reroll the check with a -1 penalty, and can use that result instead. This can go on for multiple turns so long as your character does nothing else and can keep concentrating on their bending, though the penalty on the check increases by 1 each time.

All right, I think that's that for now. As always, feedback is welcome; let me know if everything I'm describing makes sense, and whether or not it sounds like something you'd want to play.

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