D&D 5E Another defenses vs. saving throws thread

[Flobby]

So, I was thinking of converting saving throws to 3 defenses like in 4e, and found that the conversion should be to X Defense = 14 + Prof + Ability mod somewhere in this forum. (Someone also suggested X Defense =10 + Prof + Ability mod + 2nd Ability mod, which is kind of cool).
At first I was thinking why not roll AC into Reflex Defense then and say certain attacks bypass armor (I know maybe it amounts to the same thing). But of course base AC starts much lower (base 10 + Ability mod + Armor bonus).
My question is a math question I guess. Why is converting saving throws to attacks so much different? Your attack bonus is + Prof + Ability mod, right? So wouldn't a spell attack be the same? Then I would think Defense would be base 10...

 

[jmartkdr2]

The two point swing is for two reasons:

1. The average of a d20 isn't 10, it's 10.5. By switching who's rolling, you change the average form 10 to 10.5 on one side, and from 10.5 to 10 on the other. Changing the static number by +1 corrects for this.

2. Since ties go to the roller, you need to increase the difficulty by 1 to keep the odds the same.

So you actually go with base 12. Or 8, depending. If you want the percentages the same. You might not care.

Incidentally, Star Wars Saga Edition did drop armor class and used reflex defense to so who got hit by a blaster shot. Armor worked on all reflex defense situations, which I think is fine at least thematically, but yeah you'd need to reintroduce touch ac if you wanted to keep all the odds the same.

 

[Flobby]

The two point swing is for two reasons:

1. The average of a d20 isn't 10, it's 10.5. By switching who's rolling, you change the average form 10 to 10.5 on one side, and from 10.5 to 10 on the other. Changing the static number by +1 corrects for this.

2. Since ties go to the roller, you need to increase the difficulty by 1 to keep the odds the same.

So you actually go with base 12. Or 8, depending. If you want the percentages the same. You might not care.

Incidentally, Star Wars Saga Edition did drop armor class and used reflex defense to so who got hit by a blaster shot. Armor worked on all reflex defense situations, which I think is fine at least thematically, but yeah you'd need to reintroduce touch ac if you wanted to keep all the odds the same.

You said two point swing, it's not a 4 point swing? (base 14 for save defenses and base 10 for AC?)
And what are you saying is a base 12? AC? Sorry, bit of an idiot when it comes to math...

I was actually thinking about Star Wars Saga Edition! I wondered how that could possibly be converted to 5e.

 

[MarkB]

I was actually thinking about Star Wars Saga Edition! I wondered how that could possibly be converted to 5e.

Well, there is SW5E. I haven't played it myself and it's more a complete 5e-compatible version, but it looks like it'd make for a similar experience. It does use saves rather than defenses though.

 

[jmartkdr2]

You said two point swing, it's not a 4 point swing? (base 14 for save defenses and base 10 for AC?)
And what are you saying is a base 12? AC? Sorry, bit of an idiot when it comes to math...

I was actually thinking about Star Wars Saga Edition! I wondered how that could possibly be converted to 5e.

two points to swap AC (so if the players are rolling defense they should be rolling d20 + AC mods vs enemies attack bonus +12)

for saves woud need to make the base defense 14, yes

 

[Flobby]

Ah, I see, thanks for clearing that up. I wonder why there is a 2 point difference between AC and saves. I would think it would be the same since weapon attacks and spell attacks have the same bonuses (Prof + Ability mod). Or is AC lower because it is assumed everyone will have some kind of armor?