Datapack and Modpack Guide

Most of Creating Space's content is data-driven, so modpack makers and datapack authors can add planets, propellants and engine designs, and change rules, without writing code. This page documents the formats, as read from the mod's codecs.

Note

The data shipped inside the mod lives in data/creatingspace/…. Some folders in the source tree end in -x (for example rocket_accessible_dimension-x, dimension-x). Those are old copies that Minecraft does not load; do not use them as a reference. The live planet data is generated into data/creatingspace/creatingspace/rocket_accessible_dimension/.

Contents: Planets · Propellants · Power packs · Exhaust packs · Block masses · Tags · Recipe types · Dimension ids

Planets and travel costs

Path: data/<namespace>/creatingspace/rocket_accessible_dimension/<name>.json, where <namespace>:<name> is the id of the dimension you are describing. The Overworld is data/minecraft/creatingspace/rocket_accessible_dimension/overworld.json. The registry is synchronised to clients.

{
  "gravity": 3.71,
  "arrivalHeight": 300,
  "orbitedBody": "creatingspace:sun",
  "distanceToOrbitingBody": 2000,
  "adjacentDimensions": {
    "creatingspace:mars_orbit": { "deltaV": 400 }
  }
}

Field	Type	Meaning
gravity	number (m/s²)	Surface gravity. 0 makes the world an orbit (rockets stop there instead of landing; players below the bottom fall to the world in orbitedBody).
arrivalHeight	integer (Y)	Where rockets and fallen players arrive in this world.
orbitedBody	dimension id, optional (default sun)	The world below an orbit. Used for the "falling out of orbit" rule.
distanceToOrbitingBody	integer	Stored with the data, not used by the current game logic.
adjacentDimensions	map	Direct connections from this world: key is the destination dimension id; deltaV is the cost in m/s.
adjacentDimensions.*.arrivalHeight	integer, optional (default 64)	Accepted for compatibility; the game uses the destination world's own arrivalHeight instead.

Rules:

• Connections are one-way: write both directions if you want both.
• The game computes the cheapest route between any two worlds (Dijkstra) from these edges. A rocket can choose as destination any world that has at least one connection leaving it.
• Gravity and arrival height are looked up per world, and missing worlds default to 9.81 m/s² and Y 64.
• You must also define the dimension and its dimension type yourself (standard Minecraft datapack files). The mod's own examples are in data/creatingspace/dimension/ and dimension_type/.
• The mod's gravity scaling on entities does not apply to dimensions in the ad_astra or ad_extendra namespaces.

Propellant types

Path: data/<namespace>/creatingspace/propellant_type/<name>.json

{
  "propellantRatio": {
    "creatingspace:liquid_oxygen": 2,
    "creatingspace:liquid_methane": 1
  },
  "maxIsp": 460,
  "Cp": 4500,
  "gamma": 1.1,
  "M": 18
}

Field	Meaning
propellantRatio	Map from a fluid tag id to a weight. The weights are normalised into a mass fraction. The engine looks for fluids in the rocket tagged with each id (for example creatingspace:liquid_oxygen is a fluid tag).
maxIsp	The ISP, in seconds, of a perfect engine with this propellant.
Cp	Specific heat. Higher means a cooler flame (see Engine Design Reference).
gamma	Heat-capacity ratio (about 1.1 to 1.3).
M	Mean molar mass of the exhaust, in g/mol.

The registry is synchronised to clients. Single-fluid propellants (like Premixed methalox) are supported as well as two-fluid ones.

Power packs

Path: data/<namespace>/creatingspace/power_pack_type/<name>.json

{ "combustionEfficiency": 0.9, "numberOfPumps": 2,
  "allowedPropellants": ["creatingspace:methalox", "creatingspace:lh2lox"] }

combustionEfficiency scales the flame temperature (and with it ISP). numberOfPumps is read but not used by any code. allowedPropellants lists propellant ids; a pack with an empty list is hidden from the table.

Exhaust packs

Path: data/<namespace>/creatingspace/exhaust_pack_type/<name>.json

{ "minExpansionRatio": 2, "maxExpansionRatio": 100,
  "allowedPropellants": ["creatingspace:methalox"] }

The expansion-ratio slider on the table spans minExpansionRatio to maxExpansionRatio. These also feed the engine mass formula. The shipped files contain a slots field that the loader ignores.

Making a new design usable

A new power or exhaust pack also needs:

1. A translation key power_pack_type.<namespace>.<name> or exhaust_pack_type.<namespace>.<name>.
2. A picture for the table screen at assets/creatingspace/textures/gui/rocket_engineer_table/<name>.png (the screen always looks in the creatingspace namespace).
3. Assembly recipes that produce the power pack or exhaust pack item from an Engine Blueprint carrying engineRecipeData with the matching powerPackType / exhaustPackType (copy an existing file under data/creatingspace/recipe/engine_recipe/).
4. A way for players to unlock it: a Design Blueprint item with custom data {"design": "<namespace>:<name>", "design_type": "creatingspace:power_pack_type"} (or creatingspace:exhaust_pack_type), for example inside a loot table with minecraft:set_components. The shipped chests do exactly this.

Block masses

Path: data/creatingspace/creatingspace_utilities/blocks_mass.json

{ "values": { "minecraft:iron_block": 7800, "#minecraft:logs": 600 } }

Keys are block ids or #-prefixed block tags; values are kilograms. Unlisted blocks weigh 1 000 kg. A datapack that supplies this file replaces the whole file (the highest-priority pack wins), so copy the default list and edit it. Block entities that report their own mass (the Rocket Engine) ignore the table.

Tags

Tag	Used for
Biome tag creatingspace:no_oxygen	Which biomes are airless. Includes the other biome tags is_moon, is_mars, is_venus.
Entity tag creatingspace:space_creatures	Entities immune to vacuum damage (skeleton by default).
Item tag creatingspace:oxygen_sources	Chest items that count as oxygen backtanks.
Item tag creatingspace:spacesuit	Items that count toward a "full suit".
Fluid tags creatingspace:liquid_oxygen, liquid_hydrogen, liquid_methane, liquid_co2, monopropellant	The propellant and oxygen fluids. Add other mods' fluids to these tags to make them usable as propellant.

Recipe types

Type	Machine	Key fields
creatingspace:air_liquefying	Air Liquefier	blockInFront (block id), dimension (optional dimension id), processing_time, fluid results
creatingspace:mechanical_electrolysis	Mechanical Electrolyzer	fluid ingredients, fluid results, processing_time
creatingspace:chemical_synthesis	Catalyst Carrier	fluid ingredients, optional catalyst (an item ingredient; leave it out for no catalyst), heat_requirement, fluid results, processing_time

The shipped examples are under data/creatingspace/recipe/.

Dimension ids

creatingspace:earth_orbit, creatingspace:moon_orbit, creatingspace:the_moon, creatingspace:mars_orbit, creatingspace:mars, creatingspace:venus, plus minecraft:overworld.