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Grod_The_Giant
2012-07-02, 07:54 PM
Has anyone tried running a d20 system using an alternate die, such as 2d10 or 3d6, to get a more balanced bell curve? How does it change the feel of the game? Is it worth it?

Foxwarrior
2012-07-02, 08:00 PM
Well, there are two major changes:

Things that didn't have a 50% chance of happening have more extreme probabilities than they used to - if something is really hard to hit with a d20, it'll be much harder to hit with 2d10 or 3d6 (natural 20's only 1% of the time, and so on). This also means that it's more worthwhile to gather cover bonuses, flanking, etcetera, when you have an approximately 50% chance of hitting or being hit.

It becomes basically impossible to roll more than one attack or save at a time. Colored dice can help, I suppose.

The Dark Fiddler
2012-07-02, 08:42 PM
Well, there are two major changes:

Things that didn't have a 50% chance of happening have more extreme probabilities than they used to - if something is really hard to hit with a d20, it'll be much harder to hit with 2d10 or 3d6 (natural 20's only 1% of the time, and so on). This also means that it's more worthwhile to gather cover bonuses, flanking, etcetera, when you have an approximately 50% chance of hitting or being hit.

It becomes basically impossible to roll more than one attack or save at a time. Colored dice can help, I suppose.

Since multiple dice will tend towards the middle of the distribution, it also means that any roll where the difficulty was on the extreme edge of your capabilities (e.g. a +15 attack versus a 31 AC (requires a 16 to pass) or AC 19 (requires a 3 to fail)) will be even more or less likely to succeed.

Grod_The_Giant
2012-07-02, 08:44 PM
I understand the probability changes. I'm wondering how it affects the feel of the game.

Blisstake
2012-07-02, 09:13 PM
Well, in my spare time, my friends and I played a system of my creation using 3d6 instead of a d20. Personally I strongly prefer 3d6 since it makes each +1 more important, and makes things like 3's and 18's completely stand out.

JustPlayItLoud
2012-07-02, 09:42 PM
A friend of mine is running a game that I occasionally make a "guest appearance" in (not that I'm in any way special enough to make guest appearances) that uses 2d10 in place of all 1d20 rolls. I hate it. I understand the reasoning behind it in that it reduces the impact of random variance, but I ultimately prefer a straight d20 roll. I've played other systems that use multidice rolling mechanics that work well, but I feel like a game is best using the dice system it was originally intended to use.

It makes rolling feel like more of a foregone conclusion to me, at least in 3.5. When most of the rolls land in the 9-12 range, there aren't as many surprises as to the results of rolls. Sometimes it feels like you might as well be taking 10 on everything. Some arguments in favor are that it makes 2s and 20s more exciting because they only happen 1% of the time. Maybe that's true, but I couldn't tell you. I think my wizard played in about five sessions and we never saw a 2 or a 20. They may be more exciting, but not if I forget they can happen before the next time I see one.

Craft (Cheese)
2012-07-02, 10:12 PM
I think bell curve rolls make for better games, but the one thing I *do* like about d20 is you can easily calculate the probability of success/failure of a roll in your head. So you can instantly know that if you have a +6 save bonus then you have a 1/5 chance of making a DC 23 saving throw. Doing this with 2d10 or 3d6 is... quite a bit more complicated.

Cespenar
2012-07-03, 05:17 AM
I don't like the d20 system. It's a system where the difference between a 10 and 18 strength is worth 4 points, but a dice roll can vary from 1 to 20. It gets somewhat more sensible in higher levels, where the static bonuses start to gain importance against pure luck, but in lower levels, it's nonsense. One might as well declare the winner of a lower level fight with a coin toss, rather than running the actual battle, and save the time.

If I'd run a, say, E6 game, I would think of replacing the d20 with not just 3d6, but a 2d6. (And adjust stuff accordingly, of course, like AC starting at 7 instead of 10.)

dobu
2012-07-03, 08:05 AM
we did roll 3d20 take middle in my campaign a while ago. this isn't exactly a bell curve, but close enough.

Generally they liked it as it felt more balanced and they didn't blame unlucky dice that much as they used to. It's an ok alternative, and you should try it, if you're concerned about the distribution of a single d20 roll.

Tyndmyr
2012-07-03, 08:20 AM
Has anyone tried running a d20 system using an alternate die, such as 2d10 or 3d6, to get a more balanced bell curve? How does it change the feel of the game? Is it worth it?

Touch attacks are more ludicrous. Disparity between strong and weak saves is more notable.

In general, it tends toward less randomness and more deterministic outcomes. This works remarkably poorly if you have a group that's good at optimization.

Jay R
2012-07-03, 09:38 AM
we did roll 3d20 take middle in my campaign a while ago. this isn't exactly a bell curve, but close enough.

Generally they liked it as it felt more balanced and they didn't blame unlucky dice that much as they used to. It's an ok alternative, and you should try it, if you're concerned about the distribution of a single d20 roll.

In fact, it's not a bell curve; it's a parabola. Vaguely similar to the middle of a bell curve, but with no flattened tails.

You can get a result of X by rolling three X's, or by rolling 2 X's and one other number, or by rolling an X, a number less than X, and a number greater than X. So the number of ways to roll any given number X is 1 + 3*19+ 6*(X-1)*(20-X).

The probability is that divided by 8,000.

Everything from 8 to 13 has a 7-7.5% chance of occurring, while a 1 or 20 has a 0.725% (less than 1%) chance. Here's the full table, if anybody cares:

1 0.725%
2 2.075%
3 3.275%
4 4.325%
5 5.225%
6 5.975%
7 6.575%
8 7.025%
9 7.325%
10 7.475%
11 7.475%
12 7.325%
13 7.025%
14 6.575%
15 5.975%
16 5.225%
17 4.325%
18 3.275%
19 2.075%
20 0.725%

dobu
2012-07-03, 12:16 PM
In fact, it's not a bell curve; it's a parabola. Vaguely similar to the middle of a bell curve, but with no flattened tails.

I know. I plotted the different curves as a quick reference. have fun with it. :smallsmile:

http://imgur.com/aXSmt
http://i.imgur.com/aXSmt.png

TheOOB
2012-07-03, 04:27 PM
Personally I think it unbalances the system. All the numbers and math of D&D are based around the d20, not 2d10 or 3d6. If you change the die rolled, you are making bonuses more powerful and penalties more nasty. D&D is already a pretty unbalanced system, do you really want to give people who know how to get bonuses an avoid penalties more power?

planswalker
2012-07-03, 06:50 PM
I've found that replacing the random d20 with a bell curving 3d6 or 2d10 means that the big get bigger and the small get smaller. It means that fights are even more determined by raw power going in and are much more predictable. In my play group, that's a bad thing, as it makes it so my pc's are either unwinnable underdogs or they're steamrolling things.

edit: it's also worth noting that 2d10 is NOT equivalent to 1d20. D20 has an average of 10.5. 2d10 has an average of 11.