What is the dice system
Towns uses a formula for calculating values for almost everything that is known as the dice system. It originally was developed (as far as I know) for Dungeons and Dragons and simulates rolling dice to get a value.
How does it work
So let's make up a fake piece of armor. Magic armor box, appear on the right!
|Crafting Benches Required|
As you can see, the defense rating for this amazing piece of armor is 4d3+12. Let's break that down:
4d: the number of dice rolled (4 dice)
3: the range of the dice (1-3)
+12: The modifier, this can be a positive, negative, or left off entirely
The minimum value you can get for this value is 16. The max is 24.
Lets do a quick simulation to understand this further:
You are rolling for dice that can come out as 1, 2, or 3.
Roll 1: 2
Roll 2: 3
Roll 3: 3
Roll 4: 1
You get your total of: 9
You then add your modifier to it (+12):
9 + 12 = 21
So your final value is 21.
So why use something like this rather than using a min or max. Well the answer is simple, more dice means that the average roll will come out higher statistically.
I wrote a quick program that will simulate rolling the dice 10,000 times each to help simulate this. Let's run it twice, once for 4d3+12 (our original stat) as well as one with only 1 die 1d12+12.
The following shows how many time the resulting value would have come out of each roll:
4d3+12  121  503  1185  1961  2337  2010  1289  477  117
1d12+12  843  834  880  848  843  771  862  800  831  800  846  842
So as you can see that 4d3+12 came out to 20 2337 times and 1d12+12 came out to 15 880 times.
Using more dice will average it out more (you can't be as lucky with every roll), while the single dice has closer to the same output for every value.