Casting defensively and getting hit in combat

[Kershek]

A wizard and an opponent are squaring off. The wizard starts casting defensively and the opponent triggers his readied action to attack. The opponent attacks and does damage. Since the wizard is casting defensively, does he get a +4 to his concentration check against the damage dealt to get the spell off?

Or is casting defensively only used to avoid an AoO?

 

[AuraSeer]

Casting defensively only protects against AoOs. It does not give a bonus to other concentration checks.

You may be thinking of the feat Combat Casting, but that doesn't help here either. It gives a +4 to the DC 15 Concentration roll for the defensive casting itself, but does not help for any other roll.

 

[Kershek]

Yes, I was thinking of Combat Casting and forgot to mention it. Thanks.

Next question - if two fighters readied an action to attack the wizard during his casting, does the wizard make two concentration checks or one concentration check totalling the damage from both sources?

How about if a fighter was attacking and there was continuing damage from a Melf's Acid Arrow? Would there be one or two concentration checks?

 

[dcollins]

Separate checks for each source of damage.

 

[Kershek]

Can you quote a source?

 

[Dr. Zoom]

You make the concentration check when you take the damage, and you don't take the damage all at once. So you can't wait until they both hit and then make one concentration check. That is how the skill works.