Calculating the AC of a character involves adding up the various sources of AC. Most of these sources do not stack, with the exception of Dodge AC. For more information Armor Class. There are six types of AC in NWN2: Armor, Deflection, Dodge, Natural, Shield and Untyped. And each subtype, other than untyped, can be a base bonus or an enhancement bonus. Base bonuses stack and tend to be granted by persistent feats, while enchancement bonuses do not stack (with the exception of Dodge which stacks to +20) and are granted by spells, equipment and spell-like feats.