Grinding Gear Games, the folks behind Path of Exile, have release Part 2 of their community Q&A about game mechanics. Let’s dive in.
In case you missed the part one of the Q&A, you can catch up here. The team discussed monster kills, various effects, mine detonation, and much more. It was pretty extensive and you should give it a read if you like the minutiae.
Part 2 also includes several extensive answer. Hilariously, it also includes a one-word answer to a question asking if spell dodge and block are rolled separately for each hit for the same spell. The team simply answered, “Yes.”
Other questions, like one asking about a crit enemy spell crit’ing on each hit or rolling separately, received much more extensive responses. In short, it depends on the spell. But Grinding Gear Games expanded,
“The way chances work is you have a percentage chance to do something, which is a number from 0 to 100. The game rolls a random number from 0 to 99, and if the chance value is higher than (not equal to) that random roll, you do the thing. It's pretty easy to see that this gives correct behaviour; the random roll can only go as high as 99, so a chance value of 100 will always happen (for performance reasons, the roll is often skipped for this case), and a chance roll of 0 is never higher than the random roll, so a chance of zero never happens. But a less obvious consequence of this, and one which critical strikes in PoE take advantage of, is that the random roll and the chance are fundamentally two separate values - and you need both to evaluate whether a crit happens.”