# D2 mechanics questions: chance to cast.

#### wildjinn

##### Diabloii.Net Member
D2 mechanics questions: chance to cast.

I'm wondering how chance to cast items are calculated and stacked upon each other. I've thought of several ways that they might be, and am curious what the right one is, since it definitely changes how you might apply CtC items, especially on a Delirium helm.

So. Let's pretend we have three skills, A, B, and C. Each has a 10% CtC when hit on an item. How is each successive chance selected?

Options I can think of:
A.) The total chance to cast something is 30%, selected from some straight distribution RNG. That's probably not right since you could probably have >100% CtC, which would screw that mechanism up pretty well unless it scales each percentage to a total 100%...but then rounding would screw with small differences in percentages to either give larger or smaller estimates...but that's probably thinking way too hard.

B.) Each CtC is calculated from the remaining percentage. i.e. CtC A is 10%, CtC B is 9%, CtC C is 8.1%. That could work, but I would assume that it randomizes skill order. Otherwise, is there some way to know the order? Some skills, if triggered often, might preclude the casting of other skills in this way. Unless they stack, but have a smaller chance to work on subsequent CtC's, like the way pierce is calculated.

C.) A random number is chosen from 100. If it's between 1-10, there's the chance to cast each and one is randomly chosen. If there were a skill D with 12%, the 1-10 would include that, as would 11-12. This seems to give people a crappy chance to cast multiple things.

Well, I'm just curious on this. My guess is that it's B, although that provides significant diminishing returns on multiple CtC items, and that seems like it might make sense, although it would decrease the usefulness of CtC items in general. I would love a response, since I want to know how often Delirium will really be cast on my merc, and it'd be nice to know how they stack based on whether or not I give him a Reaper's Toll as well for crazy cursing action on all fronts. (I totally want an undead flayer as a merc.)

#### wildjinn

##### Diabloii.Net Member
*bump* Someone wants to answer this, I'm sure.

##### Diabloii.Net Member
Hmm... as far as I know each skill is rolled for seperately, so you have 10% to cast A, 10% to cast B, 10% to cast C...

#### wildjinn

##### Diabloii.Net Member
hahahaha. of course. wow. i can't see the forest for the trees. thanks, shade. i'm going to be kicking myself for that one for awhile.

#### strijdje

##### Diabloii.Net Member
those wild djinn's nowadays :teeth: they just keep getting better and better :thumbsup:

nah serious, i tried this with several item combo's and it is just like shade said, each % gets a roll so 0% to cast A, 10% to cast B etc

robin