Why is SR necessary to the game?

[Mustrum_Ridcully]

SR models spell caster power.

Saving Throw DCs model spell level power.

.....they are quite different in both intent and execution. They do NOT "do the same thing".

That's a good point.
The main difference between spells/spell-like and supernatural abilities might indeed be this tiny difference - a spell is considered a force on its own, while a supernatural ability is a power inherent to the creature alone.

 

[werk]

Since it appears that everyone is overlooking my previous post, I'll state it again in a more easily read format.

What you seem to be confusing is the difference between

1) being able to throw off the effect or part of the effect of magic (saving throw),

2) the ability to ignore the effect of the magics of a being with a lesser ability at controlling magic (spell resistance),

3) and the ability to totally ignore certain magical effects due to an innate nature of the creature being targetted regardless of the skill of the magic wielder (immunity to certain effects).

They are three very different things that sometimes appear to give the same effect. However, the mechanics need to be separate because a single mechanic can't cover all three situations.

I really liked your post, both times I read it.

For the same reason there is this absurd mechanic called "Armor Class." SR is the same thing.

I think this is a very good analogy. Why do spells and conditions create a miss chance when they could, for simplicity, just add to the AC? Because they represent different things. One is resiliancy, the other is avoidance.

One thing is for sure, if you really want to remove SR, and then make up for the loss by altering and creating rules...you are in for a mell of a hess.

 

[Nail]

If this is so, then why does the caster get to add her stat mod to DC? And what about the Spell Focus feats, and analogous class abilities? Surely all these reflect caster power.

Only tangentially.

Put another way: "Do the DCs for a caster's spells automatically increase with level? How about the SR check?"

....And for magic items and magic effects not made by a creature, the DC is fixed to a form similar to 10 + (Spl Lvl * 1.5). As you see, it's not related to the power of the original caster.

 

[Li Shenron]

Only tangentially.

Put another way: "Do the DCs for a caster's spells automatically increase with level? How about the SR check?"

....And for magic items and magic effects not made by a creature, the DC is fixed to a form similar to 10 + (Spl Lvl * 1.5). As you see, it's not related to the power of the original caster.

It could tho.

What if the caster level (or a fraction of it) was added to the DC?

 

[Nail]

What if the caster level (or a fraction of it) was added to the DC?

Then you'd have a different DC/Saving Throw system, and it's likely the saving throws would suck, relative to the DCs. We've all seen how that could happen in 3.0e with the feats and PrCs which boosted the DCs into the stratosphere.

Moreover, the new system would allow 1st level slots to be more powerful than they should. High level casters get tons of these, so allowing the 1st level spells to be as good (DC -wise) as the 9th level slots would lead to *very* powerful Sorcerers, etc.

And on top of all of that, the new system would involve more math, and be more complicated. No more determining DCs on the fly during a game.

All in all: Not good, without an extensive re-write of the magic system, and a different type of gamer.

 

[pallandrome]

Why does SR exist? Because it gives a way for the creators of the game to make a low con, low dex, low wis enemy, who is nevertheless resistant to magic.

 

[Ridley's Cohort]

Spell Resistance could theorectically mean something unique and coherent and useful -- some posters here have given reasonable explanations.

But as a practical matter SR has never meant anything unique or coherent or necessary in any edition of D&D. 3e even rewrote every spell to explicitly support SR, but the designers were not able to maintain the distinction between Conjuration and Evocation that the logic of SR would imply.

 

[Ridley's Cohort]

The problem with Dracomeander's list is that #2 is a poor description of how SR is used by the D&D designers in any edition. Nice idea, but it does not seem to apply to D&D.

"Lesser ability at controlling magic" means what exactly when two beings with SR could both have the ability to manipute magic and are fighting each other?

 

[Li Shenron]

Well at least we're not considering something quite practical here. That the SR of creature is somewhat in line with their CR, and that an adventuring party rarely meets an opponent with a higher CR than APL + 4 (APL = average party level), or lower than APL - 4, although the latter is more possible.

If you take a look at monsters in the MM, you'd notice that there are:
- a few creatures with SR around CR + 5
- many with SR between CR + 7 and CR + 10 (e.g. Dragons, Demons)
- many with higher SR, about CR + 15 at best

If we can consider the most common case to be CR = APL (it might not be true, but at least it's not far from truth), then basically a creature with SR = CR + 11 for example, requires a caster which has CL = APL to roll a 11 to beat this SR. That's simply a 50% chance.

It should not be terribly difficult to figure out at that CR what could be a ST bonus that goes close to the same effect.

Taking away CL from the computation definitely changes things a lot, but you're not so likely to see it happen in games where the opponents are always within a CR range around your party. That +/-4 would result in +/-20% chance, something not to be ignored but neither game-breaking.

 

[Ridley's Cohort]

It should not be terribly difficult to figure out at that CR what could be a ST bonus that goes close to the same effect.

I would guestimate a CR = APL monster would succeed "most" of the time with its strong save(s) and fail "most" of the time with its weak save(s). "Most" would be in the ballpark of 70%.

That would suggest a racial ST mod against magic of +2 or +4 for a strong save, +6 or +8 for a weak save.