SR as a reduction in caster level

[Fifth Element]

I've never been a fan of Spell Resistance (or Magic Resistance in earlier days). I don't like the additional roll that needs to be made, the additional chance for the creature to completely avoid the effects of a spell (that's what saves are for, aren't they?).

I had a thought the other day. What if you changed SR so that spells cast upon such a creature would have their effective caster levels reduced? A 10th-level wizard throws a fireball at a creature with SR 5. The fireball causes only 5d6 damage, rather than 10d6, since the effective caster level is reduced by 5. (The spell would cause normal damage to non-SR creatures in its area of effect.)

Obviously this would only affect the bits of the spell directly affecting the creature - range would be unaffected. But duration and damage dice would be reduced for a creature with SR.

One benefit is reducing the "unfun" of a spellcaster facing a creature with high SR that is very difficult to overcome. At least the spells would have some reduced effect, rather than none.

I haven't looked at the math at all to determine a good way to translate the RAW SR numbers into this variant. Just thinking out loud, really.

 

[Archade]

OK ... currently, a drow gets SR 5 + class level, so a CR 3 drow has a SR of 8. That means a party of under level 8 can't effect them? That's no fun.

I could see house ruling a feat "Persistent Spell Penetration" or the like that says instead of making a SR check, the spell is cast at effective level 3 + CL - SR. That might work. So for the Drow example above, the CL of a 3rd level caster would be 1st. You'd have to check other monsters SR vs CR to see if it would work ...

 

[Pyrex]

I love this in concept, but there are a few holes that need to be addressed:

1) As Archade noted, you can't just use SR at their listed values, you need to rescale them somehow. Something along the lines of -10 then halve what's left.

So that a 5th level Drow Wizard (Drow actually have SR 12+Lvl, not 5+lvl) would have his typical SR 17 reduced to -3 CL. Which takes a pretty huge bite out of the CL 4-7 spells coming his way.

2) What about spells that dont meaningfully scale by caster level like Blindness?

3) Do spells reduced below their minimum CL work at all or are they negated? (i.e., a caster level 7 fireball against someone with SR 3 or more)

 

[Fifth Element]

OK ... currently, a drow gets SR 5 + class level, so a CR 3 drow has a SR of 8. That means a party of under level 8 can't effect them? That's no fun.

Please note the part of my OP where I mention that I haven't looked at the math of how to translate current SR values to this idea. I'm not suggesting the use of current values. They would need to change.

 

[Fifth Element]

2) What about spells that dont meaningfully scale by caster level like Blindness?

Not sure. Maybe a bonus to the save equal to 1/2 the SR? That's a bit clunky. Any other ideas?

3) Do spells reduced below their minimum CL work at all or are they negated? (i.e., a caster level 7 fireball against someone with SR 3 or more)

My first thought is negation. That would retain some of the current flavour of SR, where a low-level caster has no chance of affecting a high-SR baddie.

 

[Pyrex]

My first thought is negation. That would retain some of the current flavour of SR, where a low-level caster has no chance of affecting a high-SR baddie.

One problem with that is you get some really funkyness like a level 17 mage casting a 9th level spell at a 1st level flunky with SR 1 and having it fail totally.

I think a tiered approach mabye. If you assume that SR ranges from 1 to 10 then:

SR reduces the spells caster level by it's value to a minimum of the minimum allowable for that spell (i.e., min CL of 5 for Fireball).

If you SR would be enough to reduce below it's min caster level *and* your SR is higher than that spells level, then the spell is negated.

Example SR 4 against:

Fireball, CL 5: negated.
Fireball, CL 10: Reduced to CL 6

Cone of Cold, CL 9: No reduction? Hmmm
Cone of Cold, CL 12: Reduced to CL 12.

 

[Primitive Screwhead]

Reducing the caster level would add a level of complexity that I would not want in my games..having to figure out how many dice a fireball deals to a group of SR critters.. not fun.

I would lean towards having SR become a bonus to saves vs spells, and/or possibly have 'Mettle'/'Evasion'/etc... effects..

So perhaps 1/2 level to saves and take only half damage on a failed save?

 

[Fifth Element]

One problem with that is you get some really funkyness like a level 17 mage casting a 9th level spell at a 1st level flunky with SR 1 and having it fail totally.

I think one of us is confused. A level 17 wizard casts at a 17 Caster Level. Casting at a SR 1 creature (using my idea) would result in effective Caster Level 16. So the damage and/or duration might be a bit less, but the spell would not fail.

 

[Kahuna Burger]

3) Do spells reduced below their minimum CL work at all or are they negated? (i.e., a caster level 7 fireball against someone with SR 3 or more)

No. Minimum caster level should always, imo, be dealt with as a minimum voluntary caster level - negative effects or special circumstances can still reduce the effective CL (that is used to determine damage, range and duration effects). Otherwise, the ghaele cannot actually use it's prismatic spray SLA, since it requires a minimum CL of 13 and ghaeles use a CL of 12. There is also the necklace of fireballs which can cause fireballs of as low as 2d6.

 

[Pyrex]

I would lean towards having SR become a bonus to saves vs spells, and/or possibly have 'Mettle'/'Evasion'/etc... effects..

So perhaps 1/2 level to saves and take only half damage on a failed save?

Then what about spells that don't allow saves?