Eliminating extra numbers: Arcane Spell Failure

[crazy_monkey1956]

Inspiration often strikes me in the moments just before I fully wake up in the morning. Such was the case this morning, having just reread the beginning of the Magic chapter in the PHB before drifting off to sleep.

Instead of a percentile roll for Arcane Spell Failure, replace it with a Concentration check, DC 15 + spell level, with the armor's armor check penalty applied.

It has the effect of getting rid of one of the many extra numbers in the game. It also has the fringe benefit of restoring the image of elven chain and mithral shirts being "caster's" armor. High level casters with max ranks in Concentration will be better protected.

Any points of broken-ness I may be missing?

 

[Nifft]

Concentration checks become VERY easy at high level. The "nice" thing about ASF is that there is no way to reduce or overcome it. It's a flat chance, like Concealment's miss chance, so it's equally "effective" at every level.

At 10th level, you could expect someone who cared about Concentration to have a skill check like...

Ranks: 13
Skill Focus: +3
Con bonus: +4 (includes +4 item; conservative)
- - -
Total check: 20 +d20, minimum roll = 21

15 + 5 = 20, so he could wear ACP -1 armor and cast any spell. If he could get an item which grants a Concentration bonus, he could wear that much more armor without needing to roll. There is a +10 Concentration item in the SRD.

-- N

 

[Slife]

Concentration checks become VERY easy at high level. The "nice" thing about ASF is that there is no way to reduce or overcome it. It's a flat chance, like Concealment's miss chance, so it's equally "effective" at every level.

At 10th level, you could expect someone who cared about Concentration to have a skill check like...

Ranks: 13
Skill Focus: +3
Con bonus: +4 (includes +4 item; conservative)
- - -
Total check: 20 +d20, minimum roll = 21

15 + 5 = 20, so he could wear ACP -1 armor and cast any spell. If he could get an item which grants a Concentration bonus, he could wear that much more armor without needing to roll. There is a +10 Concentration item in the SRD.

-- N

And he could add in a masterwork tool and a familar's aid another action for another +4.

 

[Kaodi]

Just change it to a straight d20 roll vs spell failure DC, and you maintain the current probabilities that you have.

Padded armour, bucklers and light shields become DC 1, leather DC 2, studded leather and heavy shields DC 3, chain shirts and hide DC 4, scale mail and breastplate DC 5, chainmail DC 6, banded mail and full plate DC 7, splint mail and half-plate DC 8, tower shields DC 10, and all DCs stack when using multiple items. Actually, I suppose the DCs would really be the added numbers for all items, +1.

 

[Blacksmithking]

Why don't you drop ASF entirely? It's unnecessary, especially if you already have twilight mithral chain shirts & bucklers in the game.

 

[der_kluge]

IMC, Ranks in Concentration can be used 1:1 to overcome ASF.

So, Wizards can eventually learn to wear heavier armor without penalty. So, the ranks overcome the % failure, and no one generally has to roll anything.

Of course, Wizards are still not proficient in the armor, so they still have to spend a feat to wear the heavy armor, unless they have a level in Fighter.

Wizards wearing plate mail is really not a big problem. Most of them will avoid it anyway. Most magic offers far better protection than armor does

 

[Dannyalcatraz]

Or you could go at it from the other direction-

Make ASF reduce the DC of the spell the target has to beat.

IOW, the more armor you wear, the easier it becomes to resist your spells' effects.

That way, the arcane casters' Concentration roll is immaterial.

 

[Laman Stahros]

Or you could go at it from the other direction-

Make ASF reduce the DC of the spell the target has to beat.

IOW, the more armor you wear, the easier it becomes to resist your spells' effects.

That way, the arcane casters' Concentration roll is immaterial.

Nice, but it doesn't quite work. ASF would be no threat to a spell that doesn't allow a save. Would make buffing spellcasters really happy.

 

[Asmor]

Why don't you drop ASF entirely? It's unnecessary, especially if you already have twilight mithral chain shirts & bucklers in the game.

Agreed. Just don't give mages any armor proficiency. If they wanna wear it, they gotta waste valuable feats.

 

[Arkhandus]

And why would they do that? There's no penalty for being nonproficient in armor, and no requirement of proficiency to wear it. The only drawbacks are suffering ASF and an armor check penalty. To a spellcaster that's no trouble at all. "Oh, I'll have trouble climbing in this because I'm nonproficient? Well I guess I always have Spider Climb, Jump, Levitate, and Fly to rely on...." "Oh, it's going to make it harder for me to hit things? Well good thing I don't really bother with swords and bows and suchlike. And my Scorching Rays are really quite easy to aim, y'know."