# What a datapack can change

> Every HBM data folder a datapack can add to or change, the folder layout, and the version differences.

NTM - Continuum keeps most of its numbers in datapack files instead of code. A datapack can add to them or change them
without any Java, on all six targets. This page maps every folder HBM reads, says how copies from several packs
combine, and lists what differs between Minecraft versions. To make a pack step by step, see
[Your first datapack](https://warfactory-official.github.io/Continuum-Wiki/datapacks/first-datapack/).

## HBM's data folders

These folders are HBM's own formats. They work the same on every target.

| Folder or file | What it holds | Copies from several packs | Page |
|---|---|---|---|
| `recipe/<table>/` | Machine recipes (press, assembler, chemical plant and every other machine) | One file per recipe; top pack wins per id | [Machine recipes](https://warfactory-official.github.io/Continuum-Wiki/datapacks/recipes/overview/) |
| `recipe_removals/` | Recipes of any mod and any type to remove, by id | Every file applies | [Removing recipes](https://warfactory-official.github.io/Continuum-Wiki/datapacks/recipes/removing-recipes/) |
| `fluid_property/` | A fluid's colour, temperature, hazard diamond and traits | Top pack wins, per fluid | [Fluids](https://warfactory-official.github.io/Continuum-Wiki/datapacks/data/fluids/) |
| `fluid_property_patch/` | Changes to another mod's fluid, without replacing its file | Every patch applies | [Fluids](https://warfactory-official.github.io/Continuum-Wiki/datapacks/data/fluids/#patching-a-fluid-you-do-not-own) |
| `value_maps/<registry>/` | Per-item, per-block, per-fluid, per-entity-type and per-material values (hazards, fuels, armor, parts) | Every pack's copy merges | [Data maps](https://warfactory-official.github.io/Continuum-Wiki/datapacks/data-maps/overview/) |
| `value_maps/patches/` | Changes to another mod's data map | Applied after every copy | [Data maps](https://warfactory-official.github.io/Continuum-Wiki/datapacks/data-maps/overview/#patching-another-mods-map) |
| `fallout_transform/` | What nuclear fallout turns blocks into | Top pack wins per file; files sorted by `priority` | [Fallout transform](https://warfactory-official.github.io/Continuum-Wiki/datapacks/data/fallout-transform/) |
| `item_pool/` | Weighted loot pools (structure loot, supply drops, vending machines, satellites) | Every pack's copy merges | [Item pools](https://warfactory-official.github.io/Continuum-Wiki/datapacks/data/item-pools/) |
| `tags/` | Vanilla tags; HBM reads some of its own and many `c:` tags | Vanilla tag merging | [Tags](https://warfactory-official.github.io/Continuum-Wiki/datapacks/data/tags/) |

Any recipe file, of any type, may also carry a top-level `golem:requires` list that ties it to an `hbm.cfg` switch.
See [Removing recipes](https://warfactory-official.github.io/Continuum-Wiki/datapacks/recipes/removing-recipes/#golemrequires).

## Vanilla and loader data HBM ships

HBM also ships ordinary data in vanilla's and the loaders' formats. A datapack can replace these files with the
usual vanilla rules (the top pack wins per file):

| Folder | What HBM keeps there |
|---|---|
| `recipe/` (top level) | Crafting, smelting and other vanilla recipes. Remove them with a [removal list](https://warfactory-official.github.io/Continuum-Wiki/datapacks/recipes/removing-recipes/). |
| `loot_table/blocks/` | Block drops. |
| `advancement/` | HBM's advancements. |
| `damage_type/` | HBM's damage types (death messages, exhaustion, scaling). |
| `jukebox_song/` | HBM's music discs (26.1 and 1.21.1; 1.20.1 has no jukebox songs as data). |
| `worldgen/configured_feature/`, `worldgen/placed_feature/` | Ores, oil deposits, plants and other world features. Many placements also read `hbm.cfg` when a chunk generates. |
| `worldgen/structure/`, `worldgen/structure_set/` | HBM's structures, so `/locate` finds them. |
| `worldgen/biome/` | The crater biomes. |
| `neoforge/biome_modifier/` (NeoForge), `forge/biome_modifier/` (Forge) | Which biomes get HBM's features and mob spawns. |
| `neoforge/data_maps/item/furnace_fuels.json` (NeoForge only) | Furnace burn times of HBM's fuels. |

Points that are HBM-specific:

- Which structure spawns in a region is drawn from the weights in `hbm.cfg`, not from the `weight` values in
  `data/hbm/worldgen/structure_set/ntm_structures.json`. Changing those weights in a datapack has no effect.
- The biome tags `hbm:has_structure/<structure>` decide which biomes a structure may use, and the
  `hbm:biome_dictionary/<type>` tags tell HBM which 1.7 biome type a modded biome is. See [Tags](https://warfactory-official.github.io/Continuum-Wiki/datapacks/data/tags/#biome-tags).
- HBM's NBT structure templates are read from the mod jar, not from `data/*/structure/`. A datapack cannot replace
  their contents.
- Fabric has no biome modifier files: HBM adds the same features and spawns in code. On Fabric, change where a
  feature appears through the biome tags it uses (for example `hbm:has_feature/foxglove`) or by overriding its
  placed feature.
- HBM's extra loot in vanilla chests (dungeons, mineshafts and others) is added in code when the table loads. A
  datapack that replaces a vanilla chest table still gets HBM's extra pool.

## Folder layout

Put your files under your own namespace. Use `data/hbm/...` only for the folders that merge (HBM's data maps and
tags), or when you mean to replace one of HBM's files; prefer the patch folders and removal lists for that.

<FileTree>
- my_pack/
  - pack.mcmeta
  - data/
    - mypack/
      - recipe/ machine recipes (`recipes/` on 1.20.1)
        - press/
          - my_plate.json
      - recipe_removals/
        - removals.json
      - fluid_property/ properties of the fluid `mypack:<name>`
      - fluid_property_patch/
        - hbm/
          - oil.json changes `hbm:oil`
      - value_maps/
        - patches/
          - hbm/
            - item/
              - hazards.json changes `hbm:hazards`
      - fallout_transform/
        - my_rules.json
      - item_pool/
        - pool_supplies.json adds rows to `POOL_SUPPLIES`
    - hbm/
      - value_maps/
        - item/
          - hazards.json merges into `hbm:hazards`
    - c/
      - tags/
        - item/ `tags/items/` on 1.20.1
          - ingots/
            - uranium.json
</FileTree>

Some folders take the file's namespace from the thing it describes, others from you:

- `fluid_property/<path>.json` under namespace `ns` describes the fluid `ns:<path>`. Water is
  `data/minecraft/fluid_property/water.json`.
- A data map file sits under the map's namespace (`data/hbm/value_maps/item/hazards.json`), and every pack's copy is
  merged. A patch sits under your namespace.
- An item pool's name is the file name, in any namespace. `data/mypack/item_pool/pool_supplies.json` adds to HBM's
  `POOL_SUPPLIES`.
- `fallout_transform/` and `recipe_removals/` files can have any name in any namespace.
- A machine recipe can sit in any subfolder of `recipe/`: its `type` (`hbm:press`) picks the table. Naming the
  subfolder after the table keeps ids readable (`mypack:press/my_plate`).

## pack.mcmeta

The data pack format depends on the Minecraft version:

<Tabs syncKey="mc">
<TabItem label="26.1">
```json title="pack.mcmeta"
{
  "pack": {
    "description": "My HBM tweaks",
    "min_format": 101,
    "max_format": 101
  }
}
```
26.1 uses `min_format` and `max_format` instead of `pack_format`.
</TabItem>
<TabItem label="1.21.1">
```json title="pack.mcmeta"
{
  "pack": {
    "description": "My HBM tweaks",
    "pack_format": 48
  }
}
```
</TabItem>
<TabItem label="1.20.1">
```json title="pack.mcmeta"
{
  "pack": {
    "description": "My HBM tweaks",
    "pack_format": 15
  }
}
```
</TabItem>
</Tabs>

:::caution
A `pack.mcmeta` with a wrong key is rejected by vanilla, and the whole pack is ignored without a visible error. If
nothing in your pack seems to apply, check this file first.
:::

## Version differences

Minecraft 1.21 renamed several vanilla data folders from plural to singular. HBM writes its data in the singular
(26.1) form and its build renames the folders for 1.20.1. Your datapack must use the spelling of the version it runs on:

| 26.1 and 1.21.1 | 1.20.1 |
|---|---|
| `recipe/` | `recipes/` |
| `loot_table/` | `loot_tables/` |
| `advancement/` | `advancements/` |
| `structure/` | `structures/` |
| `tags/block/` | `tags/blocks/` |
| `tags/item/` | `tags/items/` |
| `tags/fluid/` | `tags/fluids/` |
| `tags/entity_type/` | `tags/entity_types/` |
| `tags/game_event/` | `tags/game_events/` |
| `function/` | `functions/` |
| `predicate/` | `predicates/` |
| `item_modifier/` | `item_modifiers/` |

This includes HBM's machine recipes: on 1.20.1 they are read from `data/<ns>/recipes/<table>/`. The JSON inside is the
same on every version.

Inside vanilla's own files, some shapes differ too. HBM's machine recipes, data maps and other HBM formats do not
change:

| | 26.1 | 1.21.1 | 1.20.1 |
|---|---|---|---|
| Crafting and smelting ingredient | `"minecraft:stick"`, `"#c:rods/wooden"` | `{"item": "minecraft:stick"}`, `{"tag": "c:rods/wooden"}` | as 1.21.1 |
| Crafting result | `{"id": "hbm:ingot_steel", "count": 2}` | as 26.1 | `{"item": "hbm:ingot_steel", "count": 2}` |
| Smelting result | `{"id": "hbm:ingot_steel"}` | as 26.1 | `"hbm:ingot_steel"` |
| Extra item data | `components` | `components` | NBT `tag` |
| Biome modifiers | `neoforge/biome_modifier/` (NeoForge) | `neoforge/biome_modifier/` (NeoForge) | `forge/biome_modifier/` (Forge) |

Fabric has no biome modifier files on any version. Load conditions (a file that loads only when another mod is
present) are spelled differently by each loader; see [Removing recipes](https://warfactory-official.github.io/Continuum-Wiki/datapacks/recipes/removing-recipes/#load-conditions-per-loader).

HBM's own folders keep their names on every version: `value_maps`, `fluid_property`, `fluid_property_patch`,
`fallout_transform`, `item_pool` and `recipe_removals`. Tags inside them (such as `#c:ingots/uranium` in a data map)
use the same spelling everywhere.

On 1.20.1 Forge the convention tag namespace is `forge:`, not `c:`. HBM still ships its `c:` tags there and also copies
each of them to `forge:` with the same members. Its crafting recipes read the `forge:` copies; machine recipes and data
maps keep reading `c:`. See [Tags](https://warfactory-official.github.io/Continuum-Wiki/datapacks/data/tags/#c-tags-on-1201-forge).

## When changes apply

HBM reads all of these folders when the server starts and again on every `/reload`, and sends them to every client.
You do not need to restart the game after editing a file. A file that fails to parse is skipped with a line in the
log (`[HBM] Skipped ... fluid property file(s)`, `Data map hbm:hazards: skipping ...`,
`Fallout transform file ... is broken`), and the rest of the folder still loads. A broken recipe file is reported by
the game's own recipe loader.

Worldgen changes (features, structures, biomes, biome modifiers) only affect chunks generated after the world loads
with them. `/reload` does not reload worldgen files: leave the world and open it again.

## Settings that are not datapacks

Some of HBM's behaviour is set in config files in the game's `config/` folder, not in datapacks. They apply to the
whole game or server, and most are read at start-up:

| File | What it holds |
|---|---|
| `config/hbm.cfg` | 1.7's main config: recipe modes (528 mode, LBSM, expensive mode), structure spawn weights, world generation rates, radiation and hazard switches. |
| `config/hbmConfig/hbmServer.json` | Server settings that `/ntmserver` lists and changes. |
| `config/hbmConfig/hbmClient.json` | Client display settings that `/ntmclient` lists and changes. |
| `config/hbmConfig/hbmMachines.json` | Per-machine numbers 1.7 made configurable. |
| `config/hbmConfig/hbmRadResist.json` | Per-item radiation resistance overrides. These win over the [radiation_resistance](https://warfactory-official.github.io/Continuum-Wiki/datapacks/data-maps/armor/#radiation_resistance) data map. HBM writes `_hbmRadResist.json` as a template when the file is missing. |
| `config/hbmConfig/hbmCustomMachines.json` | Player-defined custom machines. |