A true D20 game system? Has anyone ever thought about trying this?

[Quickleaf]

I was chatting with a couple guys in my group yesterday and we came up with an idea. I am certain others have had similar, so this probably isn't anything "new", but I was curious about it and wondered if anyone had ever tried it.

The idea is this: DND with no dice except the d20.

Ability scores: point-buy, standard array, or random by a table using the d20.
Money: average + d20 or max, or maybe something like anything from 2d20 to 10d20?
Attack rolls, saving throws, and skill checks all use d20's already.
Damage is always average, so you wouldn't roll for it. If you wanted it random, you could do something like d20-10, d20, 2d20, etc. however you want.
Spells could work in a similar way.

Now, personally, I know a lot of players like rolling different dice, so I am hardly saying I think this is the future of DND or anything, I'm just curious if anyone ever tried something like this idea?

This was created by Green Ronin. It was called True20.

 

[ParanoydStyle]

Edit: oh, nevermind.

 

[Horwath]

Or maybe because not just legacy but reasoned preference.

1d20 beatsx3f6 hands down for consistency. A +1 is 1 in 20 more, is an additional 5% and not maybe negligable or much more than 5% like 3d6 does.

They can both produce the same basic probability ranges - just assign the right DC to get the same odds more or less but 3d6 has inconsistent modifiers.

Ran many many years of 3d6 games btw - but the 3d6 were not a plus just a tolerated flaw in design.

problem with d20 is that lowest and highest possible outcome is equally probable as average.

And that is not how things work.

That is why they went with advantage instead of +5 bonus and minimum roll number for d20 in rogue skills with mastery.

All tools to try to subdue the swingness of d20.

 

[DND_Reborn]

problem with d20 is that lowest and highest possible outcome is equally probable as average.

And that is not how things work.

That is why they went with advantage instead of +5 bonus and minimum roll number for d20 in rogue skills with mastery.

All tools to try to subdue the swingness of d20.

While it is true most attempt at things people do should be normally distributed, the swinginess of the d20 is by design, so that rolls have a greater chance of doing incredibly well. Remember, despite common practice, there is no such thing as a critical failure/fumble, only critical hits (which are only for attacks as well, not saves or skill checks).

For people who want a more normally distributed curve for d20, I like the 4d6-4 (treat all 6's as 0's). It isn't perfectly normal, but a nice bell curve. However, if you take this approach, it makes hitting the really high ACs and DCs very difficult!

 

[WaterRabbit]

While it is true most attempt at things people do should be normally distributed, the swinginess of the d20 is by design, so that rolls have a greater chance of doing incredibly well. Remember, despite common practice, there is no such thing as a critical failure/fumble, only critical hits (which are only for attacks as well, not saves or skill checks).

For people who want a more normally distributed curve for d20, I like the 4d6-4 (treat all 6's as 0's). It isn't perfectly normal, but a nice bell curve. However, if you take this approach, it makes hitting the really high ACs and DCs very difficult!

In the category of dice that will never be used to model a game. 2d10 creates a nice bell curve without the improbability that 4d6 incurs (1 in 10 * 1 in 10 = 1 in 100) vs (1 in 6 * 1 in 6 * 1 in 6 * 1 in 6 = 1 in 1,296). Not only is the math a pain, but it swings the ends too far out. You might as well not bother with the dice at all and just use fixed numbers.

The idea behind having a curve vs linear is that a +1 modifier is much more significant. A +1 sword is actually useful.

However, I prefer exploding dice systems vs a target # like ShadowRun, Earthdawn (if you like using all of your polyhedral dice) and to some extent Storyteller. In those systems success feel more significant.

In Shadowrun in particular, the number of success influences the amount of damage done as well, so it's a double win.

 

[DND_Reborn]

In the category of dice that will never be used to model a game. 2d10 creates a nice bell curve without the improbability that 4d6 incurs (1 in 10 * 1 in 10 = 1 in 100) vs (1 in 6 * 1 in 6 * 1 in 6 * 1 in 6 = 1 in 1,296). Not only is the math a pain, but it swings the ends too far out. You might as well not bother with the dice at all and just use fixed numbers.

The idea behind having a curve vs linear is that a +1 modifier is much more significant. A +1 sword is actually useful.

However, I prefer exploding dice systems vs a target # like ShadowRun, Earthdawn (if you like using all of your polyhedral dice) and to some extent Storyteller. In those systems success feel more significant.

In Shadowrun in particular, the number of success influences the amount of damage done as well, so it's a double win.

True, the 4d6-4 method was derived because it more approximates a normal curve, not just a bell curve. I never ended up using it since it was for a game I was developing, but I always liked the math behind it.

I agree, I like a lot of the Shadowrun mechanics better than D&D and our group has explored having more of a condition monitor and soak system. But, it would involve so much tinkering it didn't seem worth it.

 

[TaranTheWanderer]

In the category of dice that will never be used to model a game. 2d10 creates a nice bell curve without the improbability that 4d6 incurs (1 in 10 * 1 in 10 = 1 in 100) vs (1 in 6 * 1 in 6 * 1 in 6 * 1 in 6 = 1 in 1,296). Not only is the math a pain, but it swings the ends too far out. You might as well not bother with the dice at all and just use fixed numbers.

The idea behind having a curve vs linear is that a +1 modifier is much more significant. A +1 sword is actually useful.

However, I prefer exploding dice systems vs a target # like ShadowRun, Earthdawn (if you like using all of your polyhedral dice) and to some extent Storyteller. In those systems success feel more significant.


In Shadowrun in particular, the number of success influences the amount of damage done as well, so it's a double win.

As I mentioned above percentile dice work well. Dangerous Journeys used a skill system that ranged from 1-100. You had to roll under your skill. Difficulty was represented like so:

Easy=skill*3
Moderate = skill*2
Hard = skill*1
Difficult = Half skill
Extreme = skill/10

01 was always a success and 100 was always a failure

Combat skills were always rolled at hard. You could parry using your combat skill and if you used a shield it was your combat skill at moderate.

So you could do the same with d20s but it’d be super swingy.

I also like shadowrun and system that use gobs of dice.

 

[WaterRabbit]

As I mentioned above percentile dice work well. Dangerous Journeys used a skill system that ranged from 1-100. You had to roll under your skill. Difficulty was represented like so:

Easy=skill*3
Moderate = skill*2
Hard = skill*1
Difficult = Half skill
Extreme = skill/10

01 was always a success and 100 was always a failure

Combat skills were always rolled at hard. You could parry using your combat skill and if you used a shield it was your combat skill at moderate.

So you could do the same with d20s but it’d be super swingy.

I also like shadowrun and system that use gobs of dice.

There is no difference between using a d20 vs using a d100. The both are flat distributions. So instead of counting by 5 you count by 1.

The other problem with flat distribution is when looking at contested actions. So a high strength vs medium strength arm wrestle for example. In a flat distribution, the lower strength person can win quite a bit more frequently because any number is equally probably. In a curved distribution, the higher strength person is going to win much more frequently and better model these types of contests.

 

[DND_Reborn]

Wow, Danergous Journeys... that is a game I haven't thought about in a long time! Gygax went a little over the top with that one IMO, although of course some elements I did like. I think I still have my books somewhere in the basement or up in the attic. LOL

 

[5ekyu]

problem with d20 is that lowest and highest possible outcome is equally probable as average.

And that is not how things work.

That is why they went with advantage instead of +5 bonus and minimum roll number for d20 in rogue skills with mastery.

All tools to try to subdue the swingness of d20.

Uhhh, wrong.

When you look at 20 stairs, 20 rungs, etc it is white normal for each step to be as far as the others.

It's simply setting that a 5 percent chance is a 5% chance.

This has nothing to do with the odds of success and failure- those are set when the DC is determined.