D6 vs D20/Polyhedrals

[Gruffty]

I am giving some consideration to buying T20.

However, my only experience of using polyhedrals and the associated game mechanics is of playing AD&D in the mid-to-late 1980s. These experiences (of using polyhedrals, playing AD&D and the game mechanics) were, shall I say, less than satisfactory, leading me to have serious doubts about the validity of polyhedrals as a basis for RPG mechanics. I was subsequently introduced to CT and have never really looked back since.

Whilst I accept that I may have been subject to some dodgy GM-ing whilst playing AD&D in the past, those experiences have left me biased towards D6 game mechanics and subsequently very reluctant to spend my hard-earned cash on a polyhedral dice + D20 game mechanic Traveller system. I am interested in T20 but also very, very sceptical of its polyhedral dice/game mechanic basis.

So...I'd like to hear peoples' views/opinions on and the pros and cons of D6 based and D20/polyhedral based game mechanics.

And, please, I'd rather this thread didn't turn into a D20 system vs. D6 system slanging match.

Thanks

Gruffty / John

 

[Malenfant]

Depends what your problem really is.

Usually when people complain about this sort of thing it's because of the probability curves. If you roll 1d(anything, usually d20), you have a flat chance for anything happening. e.g. in D&D3e a 1 is a fumble and a 20 is a critical success - usually this isn't affected by your experience, so you end up with everyone from a 1st level fighter to a 30th level one having a 5% chance to really screw up. And also, you're just as likely to roll a 1, 2, 6, 10, 15, or 20.

If you have a 2d or 3d system however, you end up with a bias toward the average roll, and the extremes become much less likely. Some people prefer this approach. Personally I think it produces more realistic results.

Polyhedrals also have the advantage of being less 'grainy' than d6. You have only 6 possible results if you roll 1d6, but you can have 20 possible results if you roll 1d20. Again, it's a matter of preference as to what people like.

 

[Fritz_Brown]

I agree w/ Malenfant about the distribution issues. So many things in life are a bell curve. For most people, life is getting along, but for a few it really sucks or is a bowl of cherries. If you use a 1d system, you have to build the bell curve into your results (a la RoleMaster's d100 system).

Interestingly, Gruffty, T20 is from d20, which is founded on (and now is the D&D system. (As I found when I went last week and looked at the site for d20.)

 

[Gruffty]

I agree that a bell curve for probabilities (2D6, 3D6, etc) is a more realistic "model of life" than a straight (D20) 5% chance model.

So how do "Feats" and skills affect probabilties (say, in a "to hit" task or throw situation) in T20? Does the use of polyhedrals have a greater effect on outcomes than, say, a 2D6 8+ to hit + skill DM scenario?

<I'll conveniently ignore the CT armour DMs on "to hit" throws - I never did understand how the type of armour a defending character is wearing could make someone "miss" their shot/to hit throw..... >

 

[robject]

My gaming group all prefer percentile-type dice -- d100 and d20s -- over Nd6. This is because they have no desire to understand the probability curve, but do want to know exactly what their odds are.

I think they're all silly for having such a preference. I think the Curve is King. But we play RuneQuest with d100, and the game runs along just fine. I think you'll be fine with d20.

As Mal said, it depends on your problem.

 

[mike wightman]

T20 can easily be played using 2d10 instead of D20 for task resolution.
Alternatively use 4d6-4 or 3d6 for simplicity.

Any of these will give a more CT feel to T20 IMHO
(I personally prefer the 2d10 method).

 

[aramis]

THere are even some arguments that 2D isn't bell-shaped; the tails are not that narrow.

3Dx is a far more bell curved than 2Dx. but 4Dx or more adds little and increases the plateau at the center.

To be honest, I've run systems with 2d6, nD6, nD10, 1D20, 2D10, etc.

the biggest problem has not been the DICE in most cases, but the difficulty scales, and when players don't have the ability to tell how many dice they get to roll until the task is announced.

Some of my favorites are
Pendragon (Both sides roll 1d20 vs skill, higher roll which is under skill succeeds; D6's for damage always the same rolls).
Storyteller 1st generation and Shadowrun Both of these are "Count Successes" mode, where skill is number of dice thrown, and each die is individually checked for success against a difficulty number. SR is d6's which open-end; ST is d10's, with 10's granting an extra die.
Arrowflight also a count success, but it's (attribute)d6's vs skill level or less; difficulty adjusts skill level.
Megatraveller and 2300 Mechanically, the task mechanics differ only in 2d6 for MT and 1d10 for 2300. simple, elegant, and VERY flexible. I actually like the 1d10 system better; my players have always preferred the 2d6.
Prime Directive Players roll xd6, and keep highest die. 6's open end, counting 5+ another die, recursively. Compare best die to difficulty nummber. Rolling average of stat + skill dice...
D6 system, especially StarWars D6 Loads of dice, but all sixes... roll and total, vs a difficulty number or an opposed roll. Fast, furious, players can grab the dice they need when they decide the action; and usually they are right.
Sorcerer xdy, where y is set by the GM for the campaign. Difficulties are also ndy; everything is an opposed roll, count successes against opposing dice.
Risk roll them dice... I've played it with other sides of dice; more sides are better up through d16... d20's tend to roll too far...
EABA Roll lots of dice, keep best three, total those three, compare to TN. Uses d6's. Could use 8's or 10's and keep a very similar feel, simply by upping the TN's. (My group talked about this during playtest, decided to not pass the result on to Greg.)
Legend of the Five Rings RPG Roll lots of D10's, keep several, total vs TN. Uses d10's. Roll skill, keep stat.

Systems I haven't liked because of their dicing:
Tales from the floating vagabond Difficulty is what determines dice thrown for tasks; maximum speed requires each player having 2d4, 2d6, 2d8, 2d10, 2d12, 2d20 and 1d100 ready... and even then, player can't grab dice until difficulty is anounced. Task labels not descriptive of actual chances of success.
Palladium Books Combat system uses different dice type (d20 Roll High) than non-combat skills (D100 Roll Low), many skills have no rollable use, but merely provide attribute modifiers.
T4 Because players can't grab dice until difficulty is announced. My players DETESTED it; I merely strongly disliked it.
AD&D there are 3 different resolution methods: Roll high 1d20, Roll low 1d20, roll low percentiles. Certain tables use 1d100 roll high.

In short, provided the players know what to roll and when, and the difficulties are set in the right ranges on the probability curve, the number of sides on the dice is not terribly important..

That being said, many people dislike handfulls of dice; others disdain low numbers of dice.

T20 is a d20 for skills, saves and combat, always roll-high. the other polyhedra are for damage use, CGen and tables only. Same with D20 syystem as a whole. If you really want a 2d system, take d20, and replace all 1d20 rolls with 2d10...

 

[Fritz_Brown]

Ooooh, hadn't thought of that 2d10 idea, Sigg. That would be a good substitute! (Wouldn't like the 4d6-4, though, for the skewing it would do, and the negative results.)

 

[Fritz_Brown]

Aramis,
I (and some of my RPG buds) liked "The Fantasy Trip" because it was all d6, so you could just grab any board game and pilfer the dice to start play. Our group liked CT (partly) for the same reason.

I liked RoleMaster because of the d100 system - it wasn't d6, but you still only needed one type of die. Also, although many people did not like the amount of paperwork, the bell curve was built into the resolution charts. It also had high and low open-ended rolling.

 

[Gruffty]

Gruffty has Shotgun-1 skill and DEX 8.

He is standing in Farmer Gileshuggan's field on Regina with a loaded shotgun (only one shell in the weapon) which does not have any scopes/sights fitted. 2 metres away is Farmer Gileshuggan's (large, empty) wood-built barn. There are no obstructions in the line of view/fire and Gruffty is not evading, taking cover or being fired upon by others.

He carefully raises the weapon, takes aim at the side of the barn, and squeezes the trigger........

To Hit: 8+ on 2D6

Applicable DMs:

Shotgun-1 skill = DM +1
Range = 2m = "Medium" = DM +3
DEX = 8 = No DM when using a shotgun
Surprise = No DM
Morale = No DM
<Ignore any possible armour DM for the barn being made of wood!>

Total DM on "To Hit" throw = +1 + +3 = +4

Gruffty throws his 2D6 and gets a 3......

Using the (very simple) CT example above, how would T20 differ in game mechanics?

 

[clementk]

Or just take a look at the 3d6 option from WotC's Unearthed Arcana.

Lots of other good ideas in that book.

d20 in general is IMO lots better than [O][A]D&D. For one thing it actually has a unified task system.

For another you really only need a d20 aside from damage. IIRC there's another mod for using d6s for damage though I may be channeling F20.

Base roll is d20 + mods >= TN (known as a DC in d20). Skills and most Feats just add another mod to the die roll. It's other aspects of base d20 / D&D3E I don't like but one nice thing about d20 is there are variants out there that fix those problems for me. There's an article on Freelance Traveller that extends the BITS Task system to T20. Useful for comparisons. Note: it uses different DC numbers than either the SRD or T20 but IIRC it or the original discussion on CotI mention the other sets of DC numbers.

Finally if you haven't already I suggest taking a look at T20 Lite available on this site and then the 3.0 d20 SRD at http://www.opengamingfoundation.org/srd.html. There's also a free adventure for T20 on this site.

HTH,
Casey

[edit] corrected task system comments and added mention of free adventure [/edit]

 

[Shadowdancer]

Originally posted by Gruffty:
Gruffty has Shotgun-1 skill and DEX 8.

He is standing in Farmer Gileshuggan's field on Regina with a loaded shotgun (only one shell in the weapon) which does not have any scopes/sights fitted. 2 metres away is Farmer Gileshuggan's (large, empty) wood-built barn. There are no obstructions in the line of view/fire and Gruffty is not evading, taking cover or being fired upon by others.

He carefully raises the weapon, takes aim at the side of the barn, and squeezes the trigger........

To Hit: 8+ on 2D6

Applicable DMs:

Shotgun-1 skill = DM +1
Range = 2m = "Medium" = DM +3
DEX = 8 = No DM when using a shotgun
Surprise = No DM
Morale = No DM
<Ignore any possible armour DM for the barn being made of wood!>

Total DM on "To Hit" throw = +1 + +3 = +4

Gruffty throws his 2D6 and gets a 3......

Using the (very simple) CT example above, how would T20 differ in game mechanics?

It's difficult to do a straight translation of your combat example without knowing the class and level of the character -- T20 uses classes and levels.

But, for the sake of the example, let's say a first-level Mercenary.

Can't remember how stats are rolled in CT, but a DEX of 8 would be real low in T20; you would receive a -1 DM to your rolls. To keep it equal to your CT example (no bonus), we'll raise it to a DEX 10.

T20 doesn't use skills for individual weapons. You have weapon feats which give you proficiency in a group of weapons. Shotgun falls under the Marksman feat, which Mercenary class characters receive at first level.

The 2m range puts the barn within the 3m range of a shotgun, so you take no penalties there -- but also no bonuses.

A first-level Mercenary has a base attack bonus (BAB) of +1.

So you're total attack DM would be: +1.

I used an online die roller for the to hit roll.

You requested that 1 roll of a 20-sided die be rolled.

Roll them bones ... your dice are

Roll 1: 9.

9 + 1 = 10. Don't know what the AC of a wood barn is, but a 10 is good enough to hit an unarmored human who receives no DEX bonus to his AC.

Having done all of that, I will say that your basic assumption of not hitting the wood barn comes from your understanding or interpretation of the CT combat procedure which does not agree with mine.

As combat was explained to me when I first learned to play D&D, and CT, the to hit roll is not necessarily what you need to hit the target, but what you need to hit the target and do damage.

In your original example, under my interpretation of the abstract mechanics of CT combat, your shot would indeed hit the barn -- the shot or whatever projectile comes out of the barrel just wouldn't hit it with sufficient force to do any noticible damage. The wood absorbed the pellets, or they deflected, or whatever.

This accounts for the low rolls which result in misses under circumstances where success would seem to be a forgone conclusion.

 

[Shadowdancer]

I forgot an important modifier in the T20 example above: size modifier. The barn, because of its size, receives a negative modifier versus your attack.

Not sure how big the barn is, but it would probably either be classifed as Large ( -1 to its AC against your attack, or basically a +1 for you to hit it ) or Huge ( -2 to its AC against your attack, or basically a +2 for you to hit it ).

But actually I think you just have to apply some common sense in this scenario, whether using T20 rules or CT rules. The barn is big, it isn't moving, and nothing impedes your shot. This isn't really a combat situation, so you should be able to hit it automatically with the shot (no matter what the rules say). If you are trying to hit a specific part of the barn -- say a small knot-hole or a small target nailed to the side of the barn, then you need to worry about your attack roles versus a target number needed to hit that spot.

 

[clementk]

T20 Gruffty, a 1st level Mercenary, has W.P. Marksman, a BAB of +1, and DEX 13. He also has the feats Weapon Focus and Weapon Specialization both applied to Shotgun. The shotgun has one shell of buckshot left against an attacking bandit (T20 Stats Green Bandit per TA#4) with DEX 11 (0 modifier) wearing jack (AR 2, +2 to AC). The bandit starts combat with Stamina 15, Lifeblood 11, and a total AC of 12.

Base To Hit Target: 12 or better

Applicable modifiers:

BAB of +1 = +1
DEX 13 = +1
Weapon Focus (Shotgun) = +1
Size of Target Medium = 0
Range 2m = 0 (under 3m)
Using buckshot = +2 to target’s AR for lifeblood damage determination; does not modify to hit

Total: +3


Case 1 Bandit wearing Jack

So the to hit roll is d20 + 3. Roll of 13 + 3 = 16. A hit!
Damage roll at 2m range is 3d6. Roll is 2, 3, 6 = 11. Weapon Specialization (Shotgun) adds 2 to the damage for 13 total.

So 13 total damage is applied to Stamina. For Lifeblood damage the AR of Jack is normally 2 but is considered 4 due to T20 Gruffty using buckshot. Starting with lowest damage rolls the 2 and 3 are removed. This leaves 2 AR unaccounted for. These are applied to the remaining damage of 8 (remaining damage roll of 6 and the 2 damage from Weapon Specialization). 8 – 2 equals 6 Lifeblood damage.

So after getting hit by the shotgun the bandit takes 13 Stamina damage and 6 Lifeblood damage and is now at Stamina 2 and Lifeblood 5. Almost unconscious and wounded the bandit is thankful that he decided to wear his heavy leather jacket today!


Case 2 Bandit without armor (same to hit and damage rolls)

If the bandit had been without armor he would instead take 13 Stamina damage and 13 Lifeblood damage and now be at Stamina 2 and Lifeblood –2. Barely conscious but dying. He would have to check (roll 15 or higher with Will and Fortitude saving throws) each round to not pass out and/or lose more Lifeblood. Further action aside from moving is possible but only in rounds where both saving throws and passed and any action made now causes another set of checks.


Case 3 critical hit on the Bandit

A critical (which would require in this instance a natural 20 then a 2nd roll at 12 or better) ignores armor as well as doubles the damage roll to 6d6+4 ((3d6+2) x 2), This would almost certainly kill the bandit. Example: 1, 1, 2, 2, 5, 6 = 17. 17+4 = 21 which equals 21 Stamina damage and 21 Lifeblood damage. Result: Stamina –6 and Lifeblood –10. The Bandit goes unconscious (which really doesn’t matter in this case) and dead at T20 Gruffty’s feet.

HTH.
Casey

[edit] Hopefully have damage added up properly all around now. Slightly reworded some parts. [/edit]

 

[mike wightman]

Casey, where has the +2 damage for Weapon Specialisation gone in the damage example?

 

[clementk]

Originally posted by Sigg Oddra:
Casey, where has the +2 damage for Weapon Specialisation gone in the daamage example?

Woops.

Between drafts and from my brain.

Just a mo, fixing.

[update] Should be fixed now. [/update]

 

[Chuck Anumia]

so Casey can hit the broad side of a Barn?...Cool

 

[jasper]

Originally posted by Gruffty:
Gruffty has Shotgun-1 skill and DEX 8.

He is standing in Farmer Gileshuggan's field on Regina with a loaded shotgun (only one shell in the weapon) which does not have any scopes/sights fitted. 2 metres away is Farmer Gileshuggan's (large, empty) wood-built barn. There are no obstructions in the line of view/fire and Gruffty is not evading, taking cover or being fired upon by others.

He carefully raises the weapon, takes aim at the side of the barn, and squeezes the trigger........

To Hit: 8+ on 2D6

Applicable DMs:

Shotgun-1 skill = DM +1
Range = 2m = "Medium" = DM +3
DEX = 8 = No DM when using a shotgun
Surprise = No DM
Morale = No DM
<Ignore any possible armour DM for the barn being made of wood!>

Total DM on "To Hit" throw = +1 + +3 = +4

Gruffty throws his 2D6 and gets a 3......

Using the (very simple) CT example above, how would T20 differ in game mechanics?

Guffy d20 Bab (attack bonus) +1
Dex 8 -1 to hit
Range 2 m no modifiers as within first range of shotgun which is 3 meters,
No feats or other skills to add to bab
Two ways of doing this but since you want to hit
AC begins at 10
barn (huge class at least ) -2
Dex 0 -5 dex mod
10 -2 - 5 = 3
Guffy needs a 3 or better to hit the barn.
Or if call it automatic hit.
You have think hardness.
Wood has hardness of 5 and for large wooden shield hit pts of 15, a door has 20, and ten by ten foot section of wall has 60. A shotgund does 3d6 so as long roll is 6 or great you have damage the barn 5 or less someone is just scratching the paint.
Look up machine gun frank to get his full service but he is mercenary 4/ army 2/ traveller 1 at 35 after going off to college and 3 terms on the prior service history. In d&d and t20 he would be a 7th level (about avg game play) character.
His bab(to hit bonus) is ... shoot I never did go back and do his bab just skills and feats looks like I have something to do later.
As I said do a search on Machine gun Frank for his full bio.
His final stats
bab (to hit bonus) +5 with shotgun
Point blank shot feat gives him +1
So his total bonus is +6 not including dex.

 

[clementk]

Originally posted by cweiskircher:
so Casey can hit the broad side of a Barn?...Cool

At 2m? Sure!

 

[Gruffty]

Originally posted by Casey:
</font><blockquote>quote:</font><hr />Originally posted by cweiskircher:
so Casey can hit the broad side of a Barn?...Cool

At 2m? Sure! </font>[/QUOTE]But CT Gruffty can't.....................

So where do T20 levels fit into all of this? How do they function in game play? How does the Levels system benefit and enhance characters?

My previous experience of the levels system left me with the impression that a 1st Level character could be wiped out easily by a 10th Level character of the same class - or perhaps that's wrong?

It's pretty straightforward in CT/MT: skills = + DM (except zero level skills). CT/MT characters simply have terms of prior service ("Marines, 4 Terms") + the skills they acquire during prior service (which can be a lot if LBBs 4,5, 6 and 7 or extended MT character generation are used).