Recently I have followed a debate on using 3d6 for gaming (as in Fantasy Trip, Melee, Wizards, & Dark City games) versus Ye Olde D20. Originally I loved the d20, but as I work on my own game, I find the ability to use multiple d6's to reflect an increase in challenge is much cleaner and easier to teach folks than add a ton of modifiers to a die roll. Anyway, I present some of the 3d6 vs. D20 debate I have seen recently for your own perusal below. Credit is given to the original writers and their points are worthy of broader exposure I think.
Both 3D6 and D20 can be used for attack rolls, and we could convert the
math such that any 3D6 roll could be roughly converted to a D20 roll
and vice versa. So, if one can be completely converted to the other,
why is one better than the other?
The answer lies partially in the mechanic of TFT character development.
The typical human character begins with attributes of 8 (with the
points to spread around, but bear with me). A 3D6 vs 8 will succeed
only 56/216 of the time. That's about 26% of the time, or about a 5 on
a D20. But the 'average' attribute for a human is 10, which succedds on
a 3D6 exactly half the time, or a 10 on a D20.
Now look at those attribute numbers, and their 3D6 and D20
counterparts. Using 3D6, a gain of 2 points gets you a 24% gain. But if
I use an attribute of 5 (for D20), it takes a gain of 5 points to get
the same benefit! (This assumes that each attribute point in D20 raises
success by 5%).
Because human (and human-like) characters have their average attributes
at 10, using 3D6 works 'better' because as one's attribute approaches
the average, one's chances for success not only improve, but improve in
proportion (roughly) to how close to the average the character is. One
improves more as a percentage the closer one is to the average. In
fact, the gain from 10 to 11 is about 12.5%, or 2.5 pips on a D20.
And because the game is mostly about human (and human-like) characters,
this works better. (I have another argument that it doesn't scale well,
that points to this average attribute thing, but stay with me for now).
Not only do those near the average get more out of their gained
attribute, those near the ends get less. So you're the greatest
swordsman -- what's another DX point really going to get you? And you,
you're incompetent, so your next point doesn't get you much, either.
Now let's look at the ends of the scale, the hoped-for triple and
double damage, and the dreaded drop and break weapon. It is not
possible with a single roll of a D20 to get a chance of something
hapening down below 5%. Yet that's an awful lot of dropped and broken
weapons (assuming that we use rolls of 19 and 20 for those). Using 3D6,
we get a dropped weapon 3/216 of the time, and a broken weapon 1/216 of
the time. We can use the characteristics of the roll to put
low-percentage outcomes at the ends of the scale -- something we can't
do (without extra rolls) with a D20.
Now let's look at difficulty.
Sure, it's easy to apply a bias to a roll to make something easier or
more difficult. But again, look at that average. If you have an
attribute of 16 (which is really high for a human), your actual penalty
with a -2 on your roll is about 8%. But the same conditions for someone
with an 11 is a hit of 25%. For a D20, a penalty of -2 is always 10%.
With 3D6, if you're really good, you can take a chance, and similarly,
if you're really bad, a penalty doesn't hurt you much.
But look again at a 3D6 mechanic for difficulty -- the extra die. With
3D6, the usual range is 3-18, with 4D6, it's 4-24. But the percentages
shift so that being average is no longer a 50% chance. Now look at the
D20. It's normal range is 1-20. But the range for 2D20 is now 2-40.
That moves the eprcentages around by a very large amount compared to a
D6. Yes, you can figure out how much to bias everything, but that's
dancing around the issue, ebcause every bias in a D20 system results in
the same percentage. The 3D6 system wins for this mechanic because it's
very easy for the GM to fine-tune rolls.
One of the things I've always liked about the TFT 3D6 system is that
it's like meta-rules. The PC figures out what the character wants to
do. The GM declares which Talents are applicable, which attribute to
roll against, and how many dice for difficulty. Then fine tune with
biases for the current situation, and roll. And if the situation comes
up again, you already know how to handle it....Neil Gilmore
Regarding how combat & armor are handled
Other people have said it but 3d6 to hit is one of my favorite things aobut TFT, and it relates to how armor is treated.
In D&D, as soon as a character can afford the best plate mail (second level, usually), that character immediately buys and wears it. Pretty much every second level fighter out there is wearing plate. In D&D, if you can afford it (and by the time they have a retinue everyone can), you load up your men-at-arms and even your peasant militia in plate armor.
In TFT, you'd be a fool to dress your peasant militia in even chain armor. The drop from an 11 or less to hit to an 8 or less to his is extreme. Add to that the fact that your peasants act last in the action round, and they're much more efficient and battle-worthy wearing no armor at all. Basically, everyone in TFT equips themselves to hover around that 10-12 DX range (with some special exceptions, like guys who want to make sure they go first in the round, or guys whose only real purpose is to stand in the front row and block opponents).
The (perhaps unintended) result is that characters and npc's in TFT are much more appropriately armed and armored than in any other dark ages/medieval game I've played. Peasants wear nothing. Mercenaries wear quilted or leather. Veterans wear chain. Elite knights wear plate. And player characters are built in a variety of ways...a Conan-type might concentrate on Strength and not wear armor despite having a lot of experience. A knightly type might pump up his dex and start with chain armor, starting with a mace and slowly working his way up to plate and bastard sword.
Bottom line: you see someone ride up to you in plate armor and in TFT you know you're facing a badass. In any other game it could just be some rich punk.
Is that realistic? Some would argue no...of course peasants would wear plate armor if they could afford it. But I'd argue yes. Peasants could NEVER afford plate armor. Historically, in an age when warriors were responsible for their own arms and armor (post Imperial rome, pre nation state), only the hardened veterans or elite members of a warrior culture (knights) were armored. In TFT, only the hardened veterans or the elite members of a warrior culture are armored. In every other game, everyone's armored. In role-playing games this is because you can't keep money out of the players' hands. In miniatures games, that's because the cost-to-benefit ratio of armor is too low. In TFT it's just right....SGT HULKA
The look, the feel, of multi-dice...
I agree with everything written about the differences in chance and
percentages between the d20 and 3d6 systems. I'd like to focus on the
tactile "feel" of the dice. I've played a lot of games that are
percentile dice based. When you shake the dice in your hand they click
and clack together and when you drop them onto a table they produce a
certain sound as they bounce around that I immediately connect with
gaming. The exact same thing is even more true when rolling 3d6. There
is simply a connection to the feel of the dice in your hands. The
poor, lonely d20 just does not give me the same feel. Multiple dice
are just more exciting to throw down than a single die. It's just like
rolling craps in Vegas. You can't wait to see and quickly add up the
numbers. While I know this is very subjective I have a feeling many of
you will identify with it. Or at least the gamblers in the group.
As strange as this may sound it's a main reason I never even bothered
to look at a d20 system....David O. Miller