Concentration checks in combat

[Renen]

I have ran into two scenarios where people handled concentration checks differently. The concentration check are for defensive casting/manifesting. Looking for some insight.

1) DM said to roll Concentration to avoid AoO. If I were to fail the check, I get attacked, but I can roll another check that adds the damage I took to the DC. If I fail the second one, then the spell/power doesnt work.

2) DM said I only get the 1st check, and failure makes the spell/power fizzle out.

Which one is the correct way? RAW wise that is.

[Fouredged Sword]

Quote from the SRD


You can use Concentration to cast a spell, use a spell-like ability, or use a skill defensively, so as to avoid attacks of opportunity altogether. This doesn’t apply to other actions that might provoke attacks of opportunity.

The DC of the check is 15 (plus the spell’s level, if casting a spell or using a spell-like ability defensively). If the Concentration check succeeds, you may attempt the action normally without provoking any attacks of opportunity. A successful Concentration check still doesn’t allow you to take 10 on another check if you are in a stressful situation; you must make the check normally. If the Concentration check fails, the related action also automatically fails (with any appropriate ramifications), and the action is wasted, just as if your concentration had been disrupted by a distraction.

The second reading is correct. If you fail the concentration check you fail to cast the spell regardless of the AOO hitting or doing damage.

[Rhynn]

Also spelled out explicitly for spells, so there's no room for confusion:


Casting Defensively
If you want to cast a spell without provoking any attacks of opportunity, you must make a Concentration check (DC 15 + the level of the spell you’re casting) to succeed. You lose the spell if you fail.

[Maginomicon]

It's worth noting that you must choose to cast defensively for any of this to matter. If you say "I cast ____" and the GM says "you provoke an AoO", it's too late to change your mind and cast defensively unless your GM's just lenient like that. This is an important distinction because you might not be aware that you're in a situation where you provoke an AoO from someone (such as an opponent you can't see), and thus a GM is prone to not let you change your mind.

I use this to great effect through psionic focus and arcane focus to get auto-defensive casting. (I still have to specify that I'm casting defensively when I declare the casting attempt, but because psionic and arcane focus each grant a "take 15" when expended on a concentration check and as is sane the concentration skill is maxed-out, it's essentially auto-defensive-casting). I also use the "cover" of darkness to get right up next to someone and let them provoke an AoO from me.

Recall that swift action spells (and immediate action spells) don't provoke an AoO regardless.

[Deaxsa]

however, if the spell fizzles, do you then provoke, or do you still not provoke?

[Renen]

I think you "already" provoked.

[Eldaran]

There's no provoke on casting defensively, regardless of if you fail or not you don't provoke.

[Kudaku]

This depends on what system you play in - 3.5 and PF handles spells differently.

In Pathfinder failing concentration checks to cast defensively fizzles the spell, but you do not suffer an AoO.

[Frosty]

This depends on what system you play in - 3.5 and PF handles spells differently.

In Pathfinder failing concentration checks to cast defensively fizzles the spell, but you do not suffer an AoO.Same thing in 3.5 really.

In PF there are FEATS that people can take (mostly fighters) that makes you provoke after you fail a defensive casting check.

[Kudaku]

Same thing in 3.5 really.

In PF there are FEATS that people can take (mostly fighters) that makes you provoke after you fail a defensive casting check.

Indeed! Which really makes it even more important that the OP posts which game he/she is playing :smallsmile: