How exactly are item modifiers rolled on items?

Hello. I am creating an educational project where I simulate the use of currency orbs on item bases and I am trying to research how exactly item modifiers are rolled on magic/rare items. Ultimately, I want to try to understand how to properly simulate mod generation.

Let's take an example. If I were to use a Chaos Orb on a pair of ilvl 84 non-influenced pair of Armour based boots, we see the following affixes:

Prefixes
# to Maximum Life
% increased Armour
% increased Armour % increased Stun and Block Recovery
# to Armour
% increased Movement Speed
% increased Rarity of Items found

Suffixes
# to Strength
% increased Rarity of Items found
Regenerate # Life per second
% to Fire Resistance
% to Lightning Resistance
% to Cold Resistance
% to Chaos Resistance
% increased Stun and Block Recovery
% reduced Attribute Requirements

Each modifier has required item level, tiers, modifier weight, tags etc.. What exactly is the formula to generate the item modifiers outcome? Another way to phrase it I guess would be what are each of the 'checks' the game goes through to determine the item mods?



EDIT: Based on some further speculation and discussion via reddit (the TRUE programming professionals kekw) I think I have a hunch on how this MIGHT work.

Let's use my previous example of using a Chaos Orb on my ilvl84 non-influenced boots.

Roll for # of affixes (4-6); lets say it rolls 4

Then roll for how many prefixes and suffixes totaling 4 mods; we'll say this rolls 2 prefixes and 2 suffixes

The game will roll 2 numbers between 1-35,000 (the total prefix mod weight) Lets say the first number rolls 8,000, resulting in T2 life. Then, the max life total weight would have to be removed from the total prefix weighting, leaving the 26,000 remaining mod weight. The game then rolls 1-26,000 and hits 17,500, resulting in T1 hybrid armour/life.

The game will repeat the previous step for the suffixes.


If anyone knows how this is exactly done, please correct me! I am very interested to understand how this process is handled.

No one outside GGG knows for sure, but your process listed works statistically so even if it is slightly different, it wouldnt matter.

For instance, it could roll from a smaller number to choose life, then roll again to choose Tier of life roll. But, as long as the total statistics add up, this should not be different than rolling it the way you describe.