Last updated: 30.06.2026

The Density Object

Rhombus introduces the Density class as the main interface for writing density functions. It is the type, worldgen developers will deal with most the time.

Object Creation

from rhombus import Density

df = Density(10)                          # constant number
df = Density("minecraft:continentalness") # referencing another function

By default, file names are not chosen but generated. To allow users to configure your datapack or let other datapacks hook into your datapack, you can set a fixed name for a density function through the following idiom:

df = "minecraft:my_variable" @ Density(5)

From Dictionary

from rhombus import Density

df = Density.from_dict({
    "type": "minecraft:mul",
    "argument1": 2,
    "argument2": "minecraft:continentalness"
})

From Datapack

from rhombus import Density
from beet import DataPack

dp = DataPack(path="pack")

df = Density.from_datapack(dp, "minecraft:overworld/sloped_cheese")

Context Awareness

Deserialization always tries to resolve references from the current datapack. So if a from_datapack() call targets a density function that somewhere in it references another one, the returned Density object will contain both completely in its abstract syntax tree.

Operators

Python Operator	Minecraft Equivalent
`+`	`minecraft:add`
`-`	`minecraft:add` with `minecraft:mul` with `-1`
`*`	`minecraft:mul`
`**`	`minecraft:square`, `minecraft:cube`, or chained `minecraft:mul` respectively
`/`	`minecraft:mul` with `minecraft:invert`
`//`
`%`
`-` (negation)	`minecraft:mul` with `-1`
`&`	`minecraft:max`
`\|`	`minecraft:min`

In-Place operators like +=, *=, etc. are supported too.

Source Generation

Dictionary

from rhombus import Density

df = Density(10) / 2

df.as_dict()

{
  'type': 'minecraft:mul',
   'argument1': 10,
   'argument2': 0.5
}

Note that the returned dictionary will contain reference strings if the Density had any, but not their definitions. You will therefore lose information if you just use this method.

Files

from rhombus import Density

df = Density(10) / 2

df.compile("main")

[
    (
        'minecraft:main', # the 'minecraft' namespace was added automatically
        WorldgenDensityFunction({
            'type': 'minecraft:mul',
            'argument1': 10,
            'argument2': 0.5
        })
    )
]

Datapack

from rhombus import Density
from beet import DataPack

dp = DataPack(path="pack")

df = Density(10) / 2

df.implement(dp, "main")

Or analogue in a Beet plugin:

from rhombus import Density
from beet import Context

df = Density(10) / 2

def beet_default(ctx: Context):
    df.implement(ctx.data, "main")