Here is an example for you Mr Strange
. Let us assume that the weapon used to carry a blow had a damage rating of 24. The game will actually use a random number between 12 (24/2) and 24 as base damage, and then apply various modifiers (power-strike, weapon proficiency, speed, etc..) to this to come up with the final number. Let us assume the final number for the magnitude of the blow is 37.
We now consider the armor. Let us asume the armor at the body part hit by the blow was 28. The game throws a random number between 14 and 28 to find the effect of armor. Let's say it got the number 22.
Now, if the weapon used was dealing cutting damage, we subtract the effect of armor directly from the blow magnitude. So we'll have:
37 - 22 = 15
If the weapon dealt piercing or blunt damage, than the effect of armor will be halved before subtraction. So we'll have:
37 - 11 = 26
But it's not yet over. The actual damage will be slightly higher than this if the blow landed on the head, and slightly lower if it landed on the legs. And also we'll multiply the result by two if this was a "Head Shot".
That pretty much summarizes it I guess.