Before we begin let me say that this is a discussion that mostly focuses on the role of piercing damage in Grim Dawn. I will also touch on why ranged weapon builds tend to be weak, especially dual pistols, but the main focus is ot remain on he armor piercing mechanic.
The in-game description of armor piercing is fairly brief and it might convince you that having a high value of armor piercing is good for your damage output. The reality is exactly the opposite - outside of very specialized builds that rely on really high amount of conversion armor piercing is actually a malus you need to avoid at all costs. But why…?
- What is armor piercing? A refresher about what armor piercing does.
What armor piercing does is that it takes some of your base physical damage and turns it into piercing damage. Physical damage is normally resisted by “Physical Resistance (PR)” and Armor (A) - in that order. Piercing damage is resisted only by “Piercing Resistance”
PR will reduce physical damage taken by a percentage. Next the check against A is made - A is a direct, linear reduction, but it can never reduce physical damage to less then 30%. The engine checks for the higher number between (Damage-A) and (Damage*30%) and applies it as HP damage.
The issue why Armor Piercing is bad is because modifiers to damage are applied after the conversion happens and for most late game characters this modifier will be at least 600-800%. These high bonuses put physical hits well over the armor values of most mobs. This means that any damage converted to pierce will lose on the huge increase in physical damage and benefit nothing from bypassing armor, since the reduction from armor remains a flat value. The reverse also applies - any character focusing on boosting piercing damage will view non-converted piercing damage as a straight damage loss, especially since that damage won’t be able to overcome armor.
Naturally, If a character is able to boost “Armor Piercing” to a very high ratio (90+) he can focus solely on getting “Increased piercing damage” boosts, of which there are plently. The Nightblade mastery offers excellent support for such a character. Unfortunately, the only way to achieve that is through the “Blades of Nadaan” constellation, which pretty much pigeon holes the player into using a 1h sword.
To make matters worse there is almost NO DEVOTION AND ITEM SUPPORT FOR BOTH PHYSICAL AND PIERICNG DAMAGE. A quick scan of the item database will reveal that only Valdun’s item set supports those damage types and it is hardly a surprise why this set is terrible… Devotion-wise only Assassin’s Blade supports physical and pierce.
- On ranged weapons
By now it should become easily apparent why ranged weapons in GD are weak, since they almost exclusively sport a high “Armor Piercing” ratio, but have no way to boost that ration to the levels enjoyed by 1h swords. Even if there was a reliable way to do that the only mastery that supports piercing damage is “Nightblade”, which has a strong focus of skils and itemization supporting melee combat.
The only successful ranged builds in GD rely on converting physical damage to other damage types and burn (Hellbore, Hellbringer) or focusing entirely on another damage type (Vortex of Souls, Gutripper). Not even builds using converted damage tend to be very strong, since usually a 100% conversion is out of reach and they are stuck using only half of their base damage.
- Outside ranged weapons
Apart from ranged weapons there is also a high number of swords and axes, which have a high-enough armor piercing ratio to greatly diminish DPS for physical builds, yet not enough to make a successful full-pierce build. I am sure a lot of time and effor was put in the creation of those items. It is kind of sad they are not used more.
- In conclusion
I hope something will be done about this design flaw. Possible solutions include:
*physical damage increase applies before conversion to pierce happen
*blades of nadaan loses weapon restriction
*new components/augments to help with armor penetration
*a lot of new items that benefit both physical and pierce
*something else
Only the first solution will solve this issue permanently. The others are mostly band-aid fixes, but even they can work too if enough effort is put forth.
