Damage reduction/resistance/etc

How do the different damage resistances and reductions work in NWN? Does a swordsmans belt (5/ ) and a vampire or crystal damage reduciton (+1/5) stack? Does the (5/ ) come off despite any magic on the weapon? And what about the percentage resistances? Are they a percentage reduction in damage or a change to avoid 100 percent of damage if you make the first percentage roll? For the reduction/resistance, does that work the same for energy damage and melee damage?

Any help on the mechanics would be appreciated!

Percentage immunities reduce dmg each time you take it(they work with resistances, and are applied before them - important)
As for reductions/resistances, x/- surpasses any weapon enchantments and it stack with x/+x reduction.
It works the same for energy and physical dmg(except there's obviously no x/+x reduction for energy).

EDIT: Also, resistances gained from feats stack with regular(magical/item) resistance.

Damage Reduction:

This comes listed in the formula: Damage Reduction X/+Y.

(Note: damage reduction will only apply to the 3 physical types of damage, Slashing, Piercing, and Bludgeoning, however, it does apply to all 3 types of physical damage all the time.)

X is the amount of physical damage damage soaked if your reduction is not ignored.

Y is the enhancement bonus OR attack bonus needed on an attacker's weapon to ignore the reduction.

For example: lets say you have bracers that give 10/+3 damage reduction. Two enemies hit you. One hits you with a +1 mace for 8 bludegoning damage, the other hits you with a +4 Longsword for 10 slashing damage.

First, the mace. It is only a +1 weapon, so it cannot ignore your damage reduction (it must be +3 or greater to do that), so you reduce the damage by 10. The mace only did 8 bludgeoning damage, so you take nothing from the blow.

Second, the Longsword. It is +4, so it ignores your damage reduction. You take ALL 10 slashing damage.

Damage Resistance:

This comes in the formula: (Type) Resistance X/-.

(Note: you may have resistance to any type of damage except magical in Aenea).

(Type) is in the name of the resistance, and describes what damage type it applies to.

X is the amount of damage that is taken off all attacks of that type. There is no way around damage resistance (other than inflicting damage of another type, you cannot ignore it with a more powerful/magical weapon/attack, etc).

For Example: You have Fire resistance 10/-, and Piercing resistance 20/-. You are struck by a Burning Hands spell for 13 fire damage, an arrow for 15 piercing damage, and a punch for 5 bludgeoning damage.

First the Burning Hands spell. It does 13 fire damage, (you fail your save), so your fire resistance soaks 10 and you take only 3 points of fire damage.

Second, the arrow. It does 15 piercing damage, your piercing resistance soaks 20. You take no damage at all (the bonus of the bow or the arrow does not matter because it is a resistance, not damage reduction).

Third, the punch. It does 5 bludgeoning damage. You have no bludgeoning resistance, so you take all 5 points.

Damage Immunity:

This comes in the formula: (Type) Immunity X%.

(Note: you may have immunity to any type of damage except magical in Aenea).

(Type) is in the name of the immunity, and describes what damage type it applies to.

X is a % value that all damage of that type is reduced by.

For example: you have 75% acid immunity. You strike a wizard with the Acid Sheath spell active and the sheath inflicts 84 points of acid damage, then he hits you with a Magic Missile spell for 16 magical damage.

First the Acid Sheath. it does 84 damage, which is instantly reduce by 75% due to your acid immunity. 75% of 84 is equal to 63. So 84 - 63 = 21. You take only 21 points of acid damage.

Then the Magic Missile hits you for 16 magical damage. You take all 16 points because you have no resistance or immunity to magical damage.

Stacking:

Each of the above types of damage avoidance will stack with the other 2 types. So you can stack Damage Reduction (reduction only works for physical damage types so you must also have resistance and/or immunity to physical damage types for it to stack) with Damage Resistance AND Damage Immunity.

For example, you have 20/+5 damage reduction, slashing resistance 10/-, piercing resistance 10/-, bludegoning resistance 10/-, slashing immunity 50%, piercing immunity 50%, and bludgeoning immunity 50%.

If you are struck by any physical damage from a source that is not at least a +5 weapon, you will first cut the damage in half due to your immunity, then you will subtract 10 from the remainder due to your resistance, and then you will subtract 20 from your damage reduction.

This means that being hit for 100 physical damage would become 50 damage due to your 50% immunity, then 40 due to 10/- resistance, then 20 due to 20/+5 reduction. Not too shabby, eh?

Only your highest resistance to a damage type will apply. Having multiple values of fire resistance, for example, will NOT stack. The only exception to this is in the case of the energy resistance feats, that are applied separately from other energy resistances.

Damage Immunities of the same type WILL stack with one another up to the cap of 100%.

From NWNwiki:

Damage reduction does not stack with itself, with a few exceptions. Instead, when a creature has multiple sources of damage reduction, the one that reduces the most damage among those that are not overcome by an attack's enhancement bonus will apply. If there is a tie, the oldest reduction effect is used. One exception to the stacking rule is that the epic damage reduction feats stack with perfect self. The other exception is that the sources of X/- damage reduction (barbarian-, dwarven defender- and epic- damage reduction) stack with each other.

Also note: a 'bug' in the NWN engine seemingly causes Damage Immunities of different values to all work as if they were the lowest value present.

For example, you have Bludgeoning Immunity 25%, and Slashing Immunity 50%.

Unfortunately, this bug will cause your slashing immunity to work as if it was 25% rather than 50%.

-bug detected by MannyJabrielle-

Note however that, if I'm not mistaken, immunities do stack. Thus you can have piecing immunity +5% and another piercing immunity +5% to make a total of 10% immunity.

evilkittenofdoom wrote:Note however that, if I'm not mistaken, immunities do stack. Thus you can have piecing immunity +5% and another piercing immunity +5% to make a total of 10% immunity.

Correct. Dunno how I forgot to type that line in, but above post has been updated.