Basically, what I’m asking if anyone knows (from testing or from a comment by the devs) if damage reduction in this game is additive or multiplicative?
Example:
I have 20% explosive damage reduction (DR) from apparel, 10% explosive DR from one skill, and 25% general DR from another skill.
If it’s added up that would be a 55% damage reduction against explosion damage, which effectively would more than double my life points
I wonder which ones you mean.
Not sure, but I think they’re all added together.
At one of the menu screens (apparell/character) you should see the total values of all your resistances.
These calculations always have been a mystery. Either they don’t work at all, they don’t work as intended or we don’t really know how they should work.
Either it should be a resistance that reduces the damage by the combined values (like 55% less damage) or they are a chance for a resistance against the damage.
In the past these values were much lower than today. Just 10% maximum, if I recall right.
Fact is, at least it seems like that, that most resistances don’t seem to work… Or they just Show these high values and still work like in the past.
And if a single bullet that hits you deals for example 10hp, a resistance of 10% just reduces it by 1. And in many cases you’re hit by more than just one bullet.
Additionally we don’t exactly know which resistances work against which weapons. Best example is the Hunters PVG. Is it a bullet or is it the splash damage that hurts the players that hard?
That was gonna be my next question: is the Gauss gun of hunters explosion or bullets ><
Maybe neither the one or the other.
The tanks big fat railguns could also be something we just don’t have protection against.
This (Tanks railguns) gun came into the game a good while ago, but also long time after apparel crafting. Maybe the devs just didn’t add a protection against it.
I have done little testing on this. Always played game in Guerrilla difficulty. This information is purely based on observations my own game play.
I have made clothing set with 20% / 20% explosive / bullet resistance. And what from this i can tell it really helps me staying alive barely. It just give me the tiny window of HP left after hits to chuck down HP packs.
For hunters railguns i haven’t noticed any difference, only game mechanic damage rubber banding / scaling to prevent player going down from single hit. Like 99% times after hit i am at 8 HP. Even not in fully health, range from 80%-100%. Below that some point hit is deadly.
My best guess it is additive. It can be also logarithmic, this would be best practice to avoid reaching 100% resistances.
Clothing DR is displayed as additive with clothing.
In order to test how they stack, you would first need a reliable damage source. Once you have that, you can isolate what damage it counts as and determine resistance stacking. Multiple trials would be needed to account for any damage ranges.
Off-hand, the only reliable damage sources I can think of are:
With video capture, you could probably add prototype runners to the list.
Made quick test, 1 run only. Did not reset skills for the test. This character has maximum health skill 3/3. Health is 130%.
Used medium fuel cell as damage source.
Without any resistances health dropped to 54 HP
10% explosion resistance 58 HP
20% explosion resistance 63 HP (here is 1 HP difference from increments of 4 HP)
40% explosion resistance 72 HP (and here is 1 HP difference again)
So base health is 130%. So that 30% (0,3) might end up doing some rounding errors on HP calculation.
But quick conclusion is: it is additive how resistances are calculated.
Very clever, I never thought of using a reliable damage source like a cell!
I’m gonna use your idea to test the max value (at my current level) later tonight. If it is indeed additive across different categories, that would be 55% (20% clothes, 10% skill, 25% ultimate skill).
(Update)
So, I coughed up the Uranium to respec, and tested the DR mechanics a bit further. Bottom line: Looks like its calculated in the least impactful way, i.e. fully multiplicative 
I used ticks for the damage tests, so all damage is explosive damage. Note that my apparel specs aren’t maxed yet, so 20% is the max DR I can get from those. DR is listed below as total DR from clothes / 10% DR skill / 25% DR skill:
no protection (0/0/0): 38 points of damage
max skill DR (0/10/25): 26 points of damage
max skill+clothes DR (20/10/25): 21 points of damage
That’s consistent with a fully multiplicative application of DR, i.e. even the two different skill DR values are applied separately:
38 x 0.8 x 0.9 x 0.75 = 20.5
So, modulo rounding, that checks out, resulting in a 46% damage reduction in total.
For comparison, if the DR would have been applied additively, the unmitigated 38 points of damage would have been reduced to 17 points of damage, for a total 55% damage reduction. Oh well.