Question about AC bonuses.

[Kagetora]

So, when talking about AC bonuses, I seem to be getting conflicting information from other players, my own mind, NWNWiki, etc.

To my understanding, you may have one each of Armor, Shield, Deflection, and Natural armor bonuses, and if you have multiples of one, the highest takes effect.  Dodge armor bonuses stack.  So, first question...this is correct, yes?  I'm 99.99% positive it is, because if I have, say, a ring and amulet +1, and cast Mage Armor on myself, I get a +2 AC boost (+1 each for Dodge and Armor, with the Natural and Deflection already provided by the items).

So, now on to the real question (assuming the above is correct).  I have been told, IG, by a couple different people, that items like my cleric's Steel Chitin Tower Shield are good because they do not give a generic Shield Bonus...they give +1 or +2 vs Piercing/Slashing/Bludgeoning (two are +1, one is +2, but I forget which right now...unimportant anyway).  So, if I cast Magic Vestment on the Shield, and give it, say, a generic +2 Shield bonus (level 8-11 caster), I am being told the Shield's bonuses stack on top of that.  So, it would be +3 vs Slashing/Piercing and +4 vs Bludgeoning, total.

I keep thinking, however, that the Spell's bonus (generic +2 or whatever) REPLACES the Shield's situational bonuses...that you get the higher of the two, but they do not stack.   In the same way that casting MW on a Silver Sword does not make it +2 vs Shapeshifters, or casting a +2 GMW on a +1 sword does not give you a +3 sword.  Only Dodge bonuses stack.

So, which is it?  Am I right, and the bonuses do not stack (according to the generic NWN and AD&D rules), or have these items somehow been specially coded to allow stacking of Armor, Shield, and other bonuses in these situations?  Would be nice to know for 100% sure whether or not I am wasting my time casting certain spells.  I think I am, but people are telling me different.

Thanks!

[Kagetora]

Oh, and as a side not in FAVOR of the argument that they stack, oddly enough, I have seen items IG that read something like "+1 Deflection Bonus" but then also have the line "+1 Deflection Bonus vs Slashing," which would seem to indicate either they DO stack, or someone didn't know how to make an item, as the second bonus would have no meaning whatsoever.

[ethinos]

To my understanding, you may have one each of Armor, Shield, Deflection, and Natural armor bonuses, and if you have multiples of one, the highest takes effect.  Dodge armor bonuses stack.  So, first question...this is correct, yes?  I'm 99.99% positive it is, because if I have, say, a ring and amulet +1, and cast Mage Armor on myself, I get a +2 AC boost (+1 each for Dodge and Armor, with the Natural and Deflection already provided by the items).

Yes, Dodge is the only AC bonus that stacks with other like AC bonuses.

So, now on to the real question (assuming the above is correct).  I have been told, IG, by a couple different people, that items like my cleric's Steel Chitin Tower Shield are good because they do not give a generic Shield Bonus...they give +1 or +2 vs Piercing/Slashing/Bludgeoning (two are +1, one is +2, but I forget which right now...unimportant anyway).  So, if I cast Magic Vestment on the Shield, and give it, say, a generic +2 Shield bonus (level 8-11 caster), I am being told the Shield's bonuses stack on top of that.  So, it would be +3 vs Slashing/Piercing and +4 vs Bludgeoning, total.

I keep thinking, however, that the Spell's bonus (generic +2 or whatever) REPLACES the Shield's situational bonuses...that you get the higher of the two, but they do not stack.

Your theory is what should be happening. I am not sure if that's the case though. It's a +2 Shield (or Armor in case of the property being placed on armor) AC vs Bludgeoning, etc., that should be applied. A general +2 Shield AC would replace the +2 vs Bludgeoning AC, not stack with it.

Oh, and as a side not in FAVOR of the argument that they stack, oddly enough, I have seen items IG that read something like "+1 Deflection Bonus" but then also have the line "+1 Deflection Bonus vs Slashing," which would seem to indicate either they DO stack, or someone didn't know how to make an item, as the second bonus would have no meaning whatsoever.

I'm leaning towards the latter. We've had items that you couldn't hold with properties that rely on being equipped for example.

[Psyche]

General AC supercedes vs AC

[Kagetora]

I guess the biggest problem is that I simply can't tell.  The situational bonuses never show up in your AC stat, and its not easy to sort through the combat messages to see if they should be hitting you when they aren't, because there are so many other variables involved (like being attacked from the side or rear when focusing on a different opponent, etc.).

Thanks for the responses so far.

[Ercvadasz]

I guess the biggest problem is that I simply can't tell.  The situational bonuses never show up in your AC stat, and its not easy to sort through the combat messages to see if they should be hitting you when they aren't, because there are so many other variables involved (like being attacked from the side or rear when focusing on a different opponent, etc.).

Thanks for the responses so far.

There is the normal armor bonus, the deflection bonus, the dodge bonus, and the natural armor bonus.
Above these there is two type of AC bonuses i am not sure if they are available here, one is called moral bonus, the other circumstance bonus. Both are only aquirable from bardic songs. (And items, no other spells can give it, to my knowledge, bards with some of their own spells are able to give it to themselves in 3.5 if i recall well. Not sure if they exist here though, never made high with a bard char.)
Moral bonus works like the rest of the AC bonuses only the highest one counts, circumstance bonus i am unsure of.
The problem with your AC is, that many times the game will think you are flat-footed even when you are not, and that it does not write out in the combat logg, when a creature that attacks you has circumstance bonus.(usually a bonus of +2 ab, e.g. with grave scarabs: one attacks you with +4 the other with +6 but occasionally with +8 cuz of the flanking and circumstance bonus.) Same with the dodge feat.
Not to mention that on occasions the symbols that say you are buffed/debuffed are removed, if you cross a transition.

I am not sure actually about the +2 deflection vs slashing AC and +1 universal deflection AC. I think that sadly at these times, the universal AC is the one it will take into account, not the specific one if you are hit by the weapon type you have the bonus against. (I have a special chain shirt, but whatever they hit me with, the roll they need to make is allways against my ac, it has +2 against one type of weapon.)

[Chaszmyr]

When you Magic Vestment your shield, do you get that message in the combat window that says 'you already have shield AC bonuses that won't stack with these shield AC bonuses'?

[Kagetora]

When you Magic Vestment your shield, do you get that message in the combat window that says 'you already have shield AC bonuses that won't stack with these shield AC bonuses'?

Yes, which should be the game telling me they don't stack.  However, the message isn't specific, and you see it in my Mage Armor example as well, even though PART of the spell is taking effect.  As I said, this is mostly an issue of what I am being told by other players.  Isn't it possible to just get a definitive answer on this, i.e. something along the lines of "nothing except Dodge bonuses stack, EVER?"  Maybe from one of the devs or people who program this stuff?

[Kenkaku]

Only Dodge bonuses stack.

All other AC bonuses overlap. The highest one take precedence with the exception of the Parry bonuses when wearing a shield.

[KoopaFanatic]

I've done a bit of experimenting with magic vestment and situational bonuses, and can confirm that they don't stack, even if they're supposed to.

ETA:  That is, a flat +1 and a +1 vs. specific damage don't stack.  If the situational bonus is larger than the general bonus, it'll supersede the general bonus for that damage type. 

[Kagetora]

Perfect.  Thanks.