Ward cumulativity

[Chazar]

I find it pretty weird how resistances stack: Having 50% and another 50% should not give 100%, but merely 75%. Go into any shop and buy something with 50% off and haggle to get another 25% off, which leaves you with a total of 62.5% off (0.5 * 0.75 = 0.375 = 1 - 0.625 = 62.5%). I think the usual way of stacking such percentage reductions should be by multiplying them...

BTW, do natural resistances always stack with anything else (e.g. the 50% poison resistance of C'tis troops)?

[Kristoffer O]

Good point.

[Chazar]

Oh, I should mention that while multiplying resistances is easy percentage math, modelling susceptibility still offers some choice:

1. We turn all percentages x% into a float via ((100-x)/100) and multiply them up to gain the resulting factor to apply to the resistable damage value.
This works as it does now: 25% resistance reduces the resistable damage by a quarter, while 25% susceptibility (= -25% resistance) adds another quarter to the damage. Yet unlike now, both do not cancel each other out: 0.75 * 1.25 = 0.9375, so resistance always outweighs susceptibility somewhat. This is natural percentage-math, and one might want it that way, but maybe some players might find it counterintuitive. On the other hand, having two resistances of 20% and 30% do not yield a total of 50% resistance anyway now (which is intended here after all!), so one would not expect 50% susceptibility to be cancelled out by them anyway (0,7*0,8*1,5=0,56*1,5=0,84)...

2. Another sensible way to model susceptibility might be the following: model susceptibility by taking the reciprocal value of the resistance factor, i.e. (100/(100-x)). So now a total of x% suceptibility exactly cancels out a total of x% resistance. But the percentage would then mean something different for susceptibility as compared to now:
20-point susceptibility adds +25%damage,
25-point susceptibility adds +33%damage,
33-point susceptibility adds +50%damage,
50-point susceptibility adds +100%damage,
100-point susceptibility means immediate death upon a single point of that damage (consider a petroleum-based-elemental getting struck by a fire dart). (Maybe as a side-effect this mechanism could also be used to model weapons like the ethereal crossbow or elf bane).
Note that this is sensible: 100% resistance make a creature totally immuny, so 100% susceptibility ought to make a creature totally vulnerable to that energy type! So I would prefer the latter model, although it turns suceptibility numbers into something other than percentage values.


I just wanted to point these simple things out - it's not the math that is difficult here, it's the mathematic modelling that matters!

[Chazar]

I also want to comment further on that matter that I think that attaining at most 99% resistance through stacking spells and items is much more in accordance with the open-ended die rolls used throughout dom2: 99% makes a unit almost immune, but there still is a chance of a high open-ended roll to score, and it would distinguish units with a native 100% immunity from troops boosted by mere items and spells (which should never give full 100% resistance,imho). (A realisic value for a high-end stacking would be something like 75%*50%*50%=93,75% just to have some example numbers.)

With the second model, debuffing spells which give susceptibility as proposed in the Wishlist thread by deccan (and in this forum somewhere else by someone else quite sometime before), would thus be a good possibility without removing innate 100% immunities, which also makes sense in my opinion: For example, you might reduce or remove an AirQueens FireResistance given to her my a mere magical ring with a hypothetical debuff-spell, but you cannot make here vulnerable to lightning, since this is her very essence...

[The_Tauren13]

Chazar said:
1. We turn all percentages x% into a float via ((100-x)/100) and multiply them up to gain the resulting factor to apply to the resistable damage value.
This works as it does now: 25% resistance reduces the resistable damage by a quarter, while 25% susceptibility (= -25% resistance) adds another quarter to the damage. Yet unlike now, both do not cancel each other out: 0.75 * 1.25 = 0.9375, so resistance always outweighs susceptibility somewhat. This is natural percentage-math, and one might want it that way, but maybe some players might find it counterintuitive. On the other hand, having two resistances of 20% and 30% do not yield a total of 50% resistance anyway now (which is intended here after all!), so one would not expect 50% susceptibility to be cancelled out by them anyway (0,7*0,8*1,5=0,56*1,5=0,84)...

This sounds like a great idea to me.