Polymorph AC question

[Rudolph]

This may be a bug, but since things are still in flux regarding polymorphing or I might have made a mistake or am right in one of my speculations below, I thought I ask you experienced shapeshifters first. I am playing a 9th lvl Hin/polymorph ogre at the moment. It has the following base stats acc. to the wiki: 21 STR, 15 CON, 8 DEX, 7 Nat AC.

Fully buffed and equipped my AC should be as follows:
10 base
+1 Small Stature
+7 Nat AC (racial)
+1 Luck of Heroes
-1 DEX mod
+2 Cat's spell
+6 IMA spell
+4 Spiderskin spell
+4 Shield Spell
+4 Deflection item
+1 Reduce Person
+1 SF (Transmutation)
__
40

However, it turns out that I only get 35 IG (an unexpected nerf that casts doubt on my end build goal). How come?

A bit of theorizing: Does the racial Natural AC not stack with the one gained through spells? I know it doesn't stack with Pale Master or Dragon Disciple AC, but I thought that was a different kind than that from spells. Also, what would be the point of giving polymorph races 4 or 5 natural AC that doesn't stack if you can get the same or better via spells. In any case, non-stacking here might explain a 4 AC difference, but could be clearer in the wiki. My second speculation concerns size AC? Does the ogre get a -1 AC and AB malus for being large? If so, that should be stated in the table, perhaps. If not, could it be that the Small Stature bonus gets removed during the polymorph? I didn't expect it to since it remains present in the feats and works in my hin Bear Warrior even in bear shape (just like other original race features do, e.g. light blindness). Where else could this AC loss come from?

[Theodore01]

Could it be, that Nat AC (from the polymorph wiki table) means the same as base AC ?

If so you base AC10 would get replaced with 7, -1 from 8dex and small size shouldn't apply if you are another race.
(just guessing here)

[Sun Wukong]

Yeah, natural AC on that list is the form's base AC, which gets boosted by the stats of the creature and all that.

[Rudolph]

Yeah, natural AC on that list is the form's base AC, which gets boosted by the stats of the creature and all that.

If that was true my AC (as calculated above - where I already count in the DEX penalty, btw) should be 30 rather than 35, shouldn't it? But it is 35, so something else must be happening...

[Rudolph]

Ok, I tested all the spell buffs IG. All of them - including Spiderskin - transfer to the ogre shape. As does the Deflection item AC. Loss of Small Stature and another -1 AC for large size seem unlikely given how size is handled in other shapeshift contexts, but they would account for 2 of the 5 lost AC points, which would still leave 3 unaccounted for (assuming there are 10 base AC and 7 natural). So something must be fishy with the polymorph form itself.

If the Natural AC mentioned on the table in the wiki refers to the base, the AC of the build should be 30 at most, which raises the question of where the 5 additional points come from.

So, any other ideas? I think this case study might yield insights that apply across the board...

[Sun Wukong]

What is your AC before any buffs?

[Sun Wukong]

Anyhow, I tested the Ogre (Mace) form on my Dwarven Shapeshifter without any spells or items... (Character that predated the Polymorph changes.)

I got 13 AC. Therefore:

13 (Base, I assume)
- 1 (Dexterity Modifier)
+ 1 (Spell Focus Transmutation)
= 13

Hence, on your halfling...

13 base
+1 Luck of Heroes
-1 DEX mod
+2 Cat's spell
+6 IMA spell
+4 Spiderskin spell
+4 Shield Spell
+4 Deflection item
+1 Reduce Person
+1 SF (Transmutation)
= 35

I think that should explain the AC. There was some talk about adjusting the forms after the graph was made. So... Yeah.

[Rudolph]

What is your AC before any buffs?

Outside ogre shape without spells or equipment:

10 base
+1 Small Stature
+1 DEX modifier
+1 Luck of Heroes
__
13

In ogre shape without spells or equipment (polymorphed straight from the above form):

???
+7 natural (whatever that means)
-1 DEX modifier
???
__
14

[Sun Wukong]

In ogre shape without spells or equipment (polymorphed straight from the above form):

???
+7 natural (whatever that means)
-1 DEX modifier
???

Yeah, the ogre form has base AC of 13. Your Luck of Heroes gives +1 AC over my dwarf in the same form. The small size bonus from Halfling no longer works as an ogre. (You are no longer small, after all.)

So... This explains the AC:
13 base
+ 1, Luck of Heroes
- 1, DEX mod
+ 2, Cat's spell
+ 6, IMA spell
+ 4, Spiderskin spell
+ 4, Shield Spell
+ 4, Deflection item
+ 1, Reduce Person
+ 1, SF (Transmutation)
= 35

[Rudolph]

Yeah, the ogre form has base AC of 13. Your Luck of Heroes gives +1 AC over my dwarf in the same form. The small size bonus from Halfling no longer works as an ogre. (You are no longer small, after all.)

That makes sense - though if Small Stature doesn't work, the ogre should strictly speaking get another malus of 1 from being large.

So the ogre has base AC 13? Does it say that anywhere? Do you know where I can find the base AC of other forms? And what about that strange +7 nat?

PS: thanks for all the testing and help!

[Sun Wukong]

That makes sense - though if Small Stature doesn't work, the ogre should strictly speaking get another malus of 1 from being large.

It might be already added in to that AC.

Do you know where I can find the base AC of other forms? And what about that strange +7 nat?

You just have to shift form without items or buffs and subtract the Luck of Heroes and Transmutation Spell Focus from the AC. As for the strange Nat +7, no idea.

[Rudolph]

Thanks, Sun Wukong,

Those pointers make sense and help. I'll test on as far as I can. Polymorph is manageable in this regard, but for Shapechange I need a high level mage who actually knows the spell, which I don't have. Ah well...

[Sun Wukong]

Hill Giant, 20 without buffs and feats.
Frost Giant, 18 without buffs and feats.
Fire Giant, 16 without buffs and feats.
Mind Flayer, 23 without buffs and feats.
Werewolf, 21 without buffs and feats.
Iron Golem, 21 without buffs and feats.
Chromatic/Metallic Dragon, 26 without buffs and feats.
Mist Dragon, 30 without buffs and feats.
Hydra, 22 without buffs and feats.
Skeleton, 23 without buffs and feats.
Zombie, 22 without buffs and feats.
Nightwalker, 24 without buffs and feats.
Planetar, 19 without buffs and feats.
Moondog, 19 without buffs and feats.
Arboreal Elf, 22 without buffs and feats.
Marut, 20 without buffs and feats.
Slaad, 24 without buffs and feats.
Erinye, 22 without buffs and feats.
Cornugon, 32 without buffs and feats.
Palrethee, 21 without buffs and feats.
Hezrou, 18 without buffs and feats.
Bebilith, 22 without buffs and feats.

[Rudolph]

Amazing! Thanks Sun.

I assume the Maur has 21?

[Sun Wukong]

Maur, hunched giant? No idea.