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Deth Muncher
2008-05-02, 03:51 PM
So, I'm wondering exactly what of these stacks:
Mage Armor
Greater Mage Armor
Shield/Repulsing Shield
Ring of Force Shield

My personal assumption is that MA and GMA don't stack, and Shield and ROFS don't stack, but I figured I should ask about all the specifics.

Sstoopidtallkid
2008-05-02, 03:56 PM
Correct. It should say in the description what type of a bonus it is, and most bonuses of the same type don't stack. There is armor(Mage Armor and mundane), shield(spell and shield), enhancement, deflection, size, dex, wis(for monks), competence, luck, and a few others. Most don't stack with themselves. An untyped bonus is usually the only one that stacks.

Spiryt
2008-05-02, 03:57 PM
An untyped bonus is the only one that stacks.

Don't dodge bonuses stack as well ?

Sstoopidtallkid
2008-05-02, 03:59 PM
Don't recall, I never have enough magic items for it to matter. I forgot to include usually in that sentence though, sorry.

Frosty
2008-05-02, 04:00 PM
Dodge bonuses always stack

Jasdoif
2008-05-02, 04:05 PM
Note that enhancement bonuses usually apply to another bonus, rather then increasing AC themselves. The enhancement bonus on a piece of armor increases the armor's armor bonus to AC. Meanwhile, the enhancement bonus on a shield increases the shield's shield bonus to AC. So you can have an enhancement bonus on your armor and an enhancement bonus on your shield without issue.

Multiple enhancement bonuses on the same piece of armor don't stack, of course; nor do multiple enhancement bonuses on the same shield.

Douglas
2008-05-02, 04:06 PM
Whenever you see a bonus, note its type. For any given type, only the highest bonus of that type applies. Once you have all your "highest of type" bonuses, each of those stacks and you add them all up.

The exceptions are: dodge bonuses, which stack without limit; circumstance bonuses, which stack as long as the circumstances causing them are different; untyped bonuses, which stack with everything but the exact same untyped bonus - untyped really means "this technically should have its own bonus type, but that type would never be used anywhere else so it would be a waste of a word to name it." Untyped bonuses are designated simply by not giving a type at all. The attack bonus from Haste is one example of an untyped bonus.

So, for your example:
Mage Armor: armor bonus
Greater Mage Armor: armor bonus
Shield: shield bonus
Ring of Force Shield: shield bonus

Mage Armor and Greater Mage Armor have the same bonus type, so only the better one applies - +6 from GMA.
Shield and a Ring of Force Shield have the same bonus type, so only the better one applies - +4 from Shield
These two bonuses then stack with each other, for a total of +10 AC.

Edit: And, yes, you need to watch out for bonuses that apply to another bonus rather than to the actual value. For example, a kobold has a +1 natural armor bonus. You might think that this would make an Amulet of Natural Armor +1 useless to kobolds because of the stacking rules, but an Amulet of Natural Armor actually gives an enhancement to natural armor bonus. Instead of providing a +1 natural armor bonus, the amulet increases the existing bonus by 1. Putting Barkskin on top of this, however, would be redundant as it does the same thing as the amulet - the better of the amulet or the spell would work, but not both.

AmberVael
2008-05-02, 04:08 PM
To quote:

A dodge bonus improves Armor Class (and sometimes Reflex saves) resulting from physical skill at avoiding blows and other ill effects. Dodge bonuses are never granted by spells or magic items. Any situation or effect (except wearing armor) that negates a character's Dexterity bonus also negates any dodge bonuses the character may have. Dodge bonuses stack with all other bonuses to AC, even other dodge bonuses. Dodge bonuses apply against touch attacks.
There are a couple important things to note here.


Dodge bonuses are never granted by spells or magic items.
Unless the developers contradict themselves within the same book, then it is okay, right? (http://www.d20srd.org/srd/spells/haste.htm)
What about twice? (http://www.d20srd.org/srd/magicItems/wondrousItems.htm#bootsofSpeed)


Dodge bonuses stack with all other bonuses to AC, even other dodge bonuses.
Note, however, that dodge bonuses to Saves do not stack. Which is a little screwy, but whatever.

Chronos
2008-05-02, 04:16 PM
I don't think there are actually any enhancement bonuses which apply directly to your Armor Class, either. What there are, are enhancement bonuses which apply to other bonuses. For instance, a lizardfolk normall has a +5 natural armor bonus to his armor class. If a 3rd-level druid casts Barkskin on that lizardfolk, he gains a +2 enhancement bonus to his natural armor bonus, meaning that his natural armor bonus is now +7. If the lizardfolk wears leather armor and a small shield, he also gets a +2 armor bonus and a +1 shield bonus. Now, a wizard comes along and enchants the lizardfolk's armor to +4 and shield to +3: The armor now has a +4 enhancement bonus to its armor bonus, and the shield has a +3 enhancement bonus to its shield bonus. So the lizardfolk now has a total of a +7 natural armor bonus to its armor class, a +6 armor bonus to its AC, and a +4 shield bonus to its AC. It does not have an enhancement bonus to its AC, even though there are enhancement bonuses involved here. But since none of them apply directly to AC, they effectively all stack.