Casting on the Defensive -- Opposed Roll?

[Aluvial]

The other night I started to question the ability to cast on the defensive. In many instances, it seems like a caster would always try this alternative than risking an AoO.

At a DC of 15 + spell level, this Concentration check is easily made by many mid level casters for their various spells.

Yes, there is a risk of failure, but with a minimal bonus for Constitution, say a +1, and the maximum ranks you can dump into it, a 9th level caster can get a +13 on this roll. Not to shabby.

It basically allows you to cast spells at anytime without to much fear of being smacked.


I propose the opposed roll for this. I'm not sure if this has come up before, but this is the method my players and I came up with recently.

Basically the caster needs to make a Opposed Check, His Concentration check minus the spell level versus the opponent (who has a AoO left) Attack Roll.

If the Caster is higher, no chance for AoO. If the Attacker is higher than roll again for the AoO attempt and follow the rules as normal.

What do you guys think? Is there another solution?

Aluvial

 

[MadScientist]

Hmm in general I thikn this method makes casting on the defensive fairly difficult. Versus a 9th level fighter it will likely be similar to setting the DC to 25 (10 + 9 BaB + 4 Str + 2 Magic) so if that wizard wanted to cast a 3rd level spell defensively onm average he would have to roll a 15, although with skill focus: concentration and combat casting (3.5 versions) he could lower this to 7(9 in 3.0), thats not to bad though.

If your comfortable with that level of difficulty I don't see a big problem with your method. Very strong creatures will be very hard to cast defensively against though. If you wanted to avoid this you could set the DC to 10 or 15 plus the opponenst BaB.

 

[Aluvial]

If your comfortable with that level of difficulty I don't see a big problem with your method. Very strong creatures will be very hard to cast defensively against though. If you wanted to avoid this you could set the DC to 10 or 15 plus the opponenst BaB.

You are right, but that is the point. Tougher creatures should be able to get the smack on the caster if he casts too close. It just makes sense. If there was a using the bow on the defensive, I would probably give it the same roll.

Same thing with Tumble. I had to make it an opposed roll. Tumbling past a dragon should be harder than tumbling past a kobold.

Same is true with casting a spell, it would be harder to do next to a dragon, easier with a kobold threatning....

Don't forget of course that if the Attacker does win the opposed check, he still has to roll for the AoO, and the Caster gets another shot to save the spell with the normal rules for damage (DC = 10 + the damage dealt).

Aluvial

 

[Grayhawk]

As far as I remeber, what you propose is identical to Monte Cook's variant from his site.


I will use the following mechanic for casting defensively in my upcomming campaign:

Casting Defensively: DC 10+spell level+ref save of threatening creature.

For one thing, this does away with the extra roll any 'opposed roll' mechanic requires.

Also, this actually makes casting defensively easier against certain creatures you meet at low levels, while still scaling as levels increase.

If you feel that BAB wouldbe more appropriate than ref save bonus, you could use that instead.

 

[Spatzimaus]

IMC we do it as an opposed roll, but a bit differently.

(I'm doing numbers off the top of my head here)

To cast defensively, make a Concentration Check:
DC = 10+spell level
If you fail, you lose the spell.
If you succeed, for every 2 points you succeed by, you receive a +1 dodge bonus to AC against all Attacks of Opportunity and Readied Actions triggered by the casting action.
(Note that 3E defensive casting doesn't stop readied actions)

That is, there's no way to entirely PREVENT the AoO, you can just raise your AC to the point where they can't really hit you. The "opposed roll" is that you're opposing the enemy's attack roll with your Concentration check.

So, for example, if I'm a level 6 Sorcerer shooting my first Fireball, and I have CON of 14 with 9 ranks of Concentration, I have a +11 skill mod. DC is 13, so if I try to cast defensively I only lose the spell on a 1, cast with no bonus on a 2 or 3, +1 AC on 4 or 5,... +4 AC if I roll a 10 or 11, up to +9 AC on a natural 20. So on average I get +4 AC, with a small chance of losing the spell.
You can't Take 10 since clearly you're under duress (why else would you be trying to cast defensively?)

Once you get past around level 8 you'll never fail the check (as long as you keep raising the skill, that is), but the AC boost might be a little less significant as you go up. Unless, of course, you play that natural 1s on skill checks are always failures, in which case the 5% chance stays.

As for Combat Casting, among other things it allows you to Take 10 on this roll even under duress (which makes a HUGE difference at low levels, since it keeps you from losing your spells).

Anyway, play with the numbers a bit if you want, but that's the general idea.

 

[MadScientist]

Interesting system Spatzimaus. I'm not sure I would use it but it is deffinately an interesting solution.

 

[ValarX]

Mage Neutralization

This mechanic is definitely an interesting one, but perhaps it is unnescesary. One thing that players tend to overlook is their ability to ready an action against certain events. For instance, an archer in the back of the party with a readied action against a caster can disrupt spells fairly well since the mage wouldn't get a concentration check against a readied action. A fighter standing next to the caster with a readied action could drop a full attack the moment the caster went to cast. These are effective ways of neutralizing the concentration check and forcing the caster into the save versus disruption of their spell. Also, for any spells that have casting times beyond one action, don't forget that any attacks against the caster that round (or the number of rounds it takes to cast) will result in the caster having to make a save.