Item Generation

Note that this section only describes items that are dropped explicitly; in addition many monsters also carry items (usually guns and ammo). Also, some level features (e.g. vaults) can cause additional items to drop beyond what is described here, as well as cause items to spawn below their usual minimum spawning depth (for example, a Red armor can spawn as early as on floor 2 in a vault).

Item placement is similar to monster placement. Every item has a minimum dlevel and a weight. Here are the levels and weights for all the items:

Ignoring minimum dlevel, the total weight for exotic items is 180. Unique items have a total weight (again ignoring minimum dlevel) of 53. Any particular unique item that is picked up by the player will never drop more than once in each game, but if it isn't picked up by the player, it may spawn again on a later floor. Minimum dlevels for items are not modified by difficulty level.

For convenience, here are the total weights for each dlevel. These allow easier calculation of the probabilities.

The number of items that appear on a level is usually ceil(21 - max(25-dlevel,0)/3). The items are chosen at random using the weights as relative probabilities. At most 1 unique item can drop per level.