D20 to 3d6

[e24ohm]

Folks:
I want to be a little different, and wanted to know if anyone has substituted 3d6 rolls for 1d20 rolls in the D20 System? I understand a few modifiers will need to be changed; however, roughly what is the breakdown of the new DC target rolls for 3d6?

The standard targets are DC10, DC15, etc…however, a DC10 would roughly be a roll of 11+ on 3d6, but I am lost for the rest of the conversion.

Thanks so much

 

[Theo R Cwithin]

There's a section in UA about Bell Curve Rolls. It's a good place to start looking up the ramifications of switching to 3d6, as well as suggestions for how to change modifiers, crits, and so on.

 

[e24ohm]

There's a section in UA about Bell Curve Rolls. It's a good place to start looking up the ramifications of switching to 3d6, as well as suggestions for how to change modifiers, crits, and so on.

Thanks for the link; however, this resource still does not detail how-to convert the DC to corresponding targets for a roll on 3d6.

 

[slwoyach]

If you modify DCs you completely negate the point of the 3d6 conversion. The extraordinary results are supposed to be more rare. The maximum roll is decreased by only 2 points, so I don't see any reason to adjust anything except critical hits (which is covered in the UA).

 

[Theo R Cwithin]

As I recall, the DCs aren't actually intended to change. That variant is meant simply to make a particular DC dramatically more difficult to beat, and to make auto-success (ie, "natural 18") a loss less frequent. Thus an adventure with a lot of DC15-20 checks becomes quite a bit more difficult because the PCs are less likely to beat those challenges rolling 3d6 as compared to d20.

I'm not sure I've seen a d20-to-3d6 conversion that also maintains the character performance relative to DC with a similar degree of "swinginess". Maybe someone else can be of more help!

 

[pawsplay]

Folks:
I want to be a little different, and wanted to know if anyone has substituted 3d6 rolls for 1d20 rolls in the D20 System? I understand a few modifiers will need to be changed; however, roughly what is the breakdown of the new DC target rolls for 3d6?

The standard targets are DC10, DC15, etc…however, a DC10 would roughly be a roll of 11+ on 3d6, but I am lost for the rest of the conversion.

Thanks so much

You have a problem. On the one hand, to get a matching skill to beat a benchmark DC, the DC must remain the same. On the other hand, to maintain the same relationship between lack of skill and difficult DCs, you need to grade higher DCs down lower. The latter is counter to the purpose of a straight conversion, while the former is counter to the desired effect of skill difference. You have to decide.

If you wanted to maximise "curvy" results while maintaining endlessly escalating skill and attack bonuses, probably the best thing to do is to keep the base DCs same, but to significantly squick the common modifiers. For instance, the standard circumstance bonus should be +1 (a difference of 12.5%, see GURPS 4e p.171).

 

[e24ohm]

As I recall, the DCs aren't actually intended to change. That variant is meant simply to make a particular DC dramatically more difficult to beat, and to make auto-success (ie, "natural 18") a loss less frequent. Thus an adventure with a lot of DC15-20 checks becomes quite a bit more difficult because the PCs are less likely to beat those challenges rolling 3d6 as compared to d20.

I'm not sure I've seen a d20-to-3d6 conversion that also maintains the character performance relative to DC with a similar degree of "swinginess". Maybe someone else can be of more help!

wow, didn't know that I would keep the same DC. With that being said, are there any modifiers to skill ranks?

 

[e24ohm]

You have a problem. On the one hand, to get a matching skill to beat a benchmark DC, the DC must remain the same. On the other hand, to maintain the same relationship between lack of skill and difficult DCs, you need to grade higher DCs down lower. The latter is counter to the purpose of a straight conversion, while the former is counter to the desired effect of skill difference. You have to decide.

If you wanted to maximise "curvy" results while maintaining endlessly escalating skill and attack bonuses, probably the best thing to do is to keep the base DCs same, but to significantly squick the common modifiers. For instance, the standard circumstance bonus should be +1 (a difference of 12.5%, see GURPS 4e p.171).

Great info; however, I do not own a copy of GURPS 4e, yet I do own GURPS 3e, but that doesn't really help me. I am not sure I understand the "standard circumstance bonus". Can you please detail?

thanks so much.

 

[pawsplay]

Great info; however, I do not own a copy of GURPS 4e, yet I do own GURPS 3e, but that doesn't really help me. I am not sure I understand the "standard circumstance bonus". Can you please detail?

thanks so much.

GURPS 3e has the same information, I believe, in the Skills benchmarks section.

By standard circumstance bonus, I mean that in d20, if there are favorable circumstances, that usually warrants a +2 bonus. In GURPs, it usually warrants a +1. Close to your average difficulty range, the two bonuses are very close mathematically.

 

[Theo R Cwithin]

wow, didn't know that I would keep the same DC. With that being said, are there any modifiers to skill ranks?

No, at least not in the variant linked above. What happens is that a single skill rank is relatively more important in 3d6 than in d20. Said another way, the ability to push a roll of, say, 13 up to 14 is a much bigger deal in 3d6 because the 14 is a much rarer roll in 3d6 compared to d20.

As pawsplay suggests, this is also why GURPS uses +1 "circumstance bonuses" rather than D&D's +2 default. So if you were to modify that variant system linked above, that change to circumstance bonses might be the place to start.