How a pack works

The content folder

Everything you add to RP Engine lives in plugins/RPEngine/content/. Each folder in there is one pack. The plugin reads them all, builds one resource pack out of them, and sends it to your players.

What can go in content/#

Each entry in content/ has to be one of these:

What you put there	How it is recognised
A content pack: your own items, models, sounds and so on, in YAML	A folder with a `pack.yml` in it. The rest of this page is about these
A resource pack, such as one exported from Studio	A `.zip`, or a folder with `pack.mcmeta` and `assets/` at the top. See Adding a resource pack
Another plugin's pack	An ItemsAdder, Nexo or Oraxen, CraftEngine, ModelEngine or BetterModel folder, copied in as it is

A folder that is none of these is skipped with a warning (see below).

A folder's name is its namespace, the first half of every ID in it (mypack:ruby). Use lowercase letters, digits, _, . and - only. See IDs and namespaces.

A content pack's layout#

plugins/RPEngine/content/
  mypack/
    pack.yml               required
    items/        *.yml
    blocks/       *.yml
    sounds/       *.yml
    music/        *.yml
    fonts/        *.yml    icons
    screens/      *.yml
    huds/         *.yml
    dialogs/      *.yml
    recipes/      *.yml
    entities/     *.yml    custom mobs
    skills/       *.yml    mob skills
    drop-tables/  *.yml
    spawners/     *.yml
    liquids/      *.yml
    vehicles/     *.yml
    emotes/       *.json or *.yml
    armor3d/      *.yml    3D armour sets
    objects/      *.yml    3D shader objects and their sequences
    text-effects/ *.yml
    vfx/          *.yml or *.json
    assets/                → assets/mypack/ in the built pack
      textures/
      models/              Blockbench files
      sounds/
    overrides/             → assets/minecraft/, for replacing vanilla art
    resourcepack/          optional: a resource pack, copied as it is
    pack.png               optional

You only need the folders you use. A pack with one item has pack.yml, items/ and assets/.

The rules#

The folder decides the kind. A file in items/ defines items, a file in sounds/ defines sounds. Top-level keys in a file are IDs, so you do not nest them under an items: key. One file can declare many things, the file name does not matter, and subfolders are only for your own organisation: items/weapons/swords.yml adds nothing to the ID.

Only the folders above are read. There is no models/ folder: a placed model is a place: block on an item. Any other folder is warned about by name, which catches typos like item/ and Sounds/.

A mistake skips one definition, not the pack. See Reloading.

pack.yml#

As short as a name:

name: My Pack

Or with everything it accepts:

name: My Pack
description: Swords and statues
author: You
version: 1.0.0
bundles: [main]      # which built packs this content goes into
enabled: true        # false skips the whole pack without deleting it

Leave bundles: out and the pack goes into main, which every player gets. See Bundles.

assets/ and overrides/#

assets/ becomes assets/mypack/ in the built pack. It is namespaced, so nothing in it can collide with another pack or with vanilla. An item mypack:ruby looks for its texture at assets/textures/item/ruby.png.

overrides/ becomes assets/minecraft/. It is how you replace vanilla art: a different dirt texture, a new font, a changed sound.

overrides/ is the one place two packs can fight

Two packs both replacing assets/minecraft/textures/block/dirt.png is a real conflict. The namespace that comes later alphabetically wins, and both are named in a build warning.

assets/models/ holds Blockbench .bbmodel project files or exported Java .json models. The .bbmodel is the better choice, because its textures are inside it. See Items.

YAML or TOML#

A definition file can be .yml, .yaml or .toml, mixed freely in one folder. They mean exactly the same thing.

[ruby]
material = "DIAMOND"
name = "&cRuby"
 
[chair.place]
facing = "cardinal"
seat = 0.5

Quote an ID with a / or a . in it

Both mean something to TOML, so weapons/sword has to be written ["weapons/sword"]. The error message says so when it happens.

If the console warns you#

/rp reload (and every startup) lists every problem at once, each with the file and the ID. The common ones:

Warning	What it means	Fix
`No pack.yml, so this is not a content pack`	The folder is not one of the shapes above. Usually a resource pack unzipped one folder too deep, so `pack.mcmeta` is not at the top	Add a `pack.yml` if it is your content. If it is a resource pack, move its contents up so `pack.mcmeta` and `assets/` sit directly inside the folder, or drop the original `.zip` in instead
`Folder name is not a valid namespace`	The folder has capitals, spaces or other characters	Rename it: `My Pack` to `my_pack`
`Not a content category, so nothing in it was read`	A folder in your pack that RP Engine does not read, often a typo (`item/`, `Sounds/`)	Rename it to one from the layout, or move art into `assets/`
`No texture at assets/mypack/textures/item/ruby.png`	The item has no picture where its ID says. It works, but shows as a purple-and-black square	Put the PNG at `content/mypack/assets/textures/item/ruby.png` (the namespace is the folder, not a folder inside `assets/`), or name another file with `texture:`
`No model at assets/models/chair.bbmodel or assets/models/chair.json`	The item says `model: chair` and no such file exists. It falls back to its flat sprite	Save the Blockbench project as `content/mypack/assets/models/chair.bbmodel`, or fix the name in `model:`
`info.namespace says X but the folder is Y, and the folder wins`	An ItemsAdder pack's config names a different namespace from its folder. Its IDs are `Y:something`	Fine as it is, unless other configs refer to `X:something`. Then rename the folder to `X`
`... already exists, so this zip was not unpacked`	A zip of that name was unpacked before, and that folder is kept in case you edited it	Delete the folder, then reload, to replace it with the zip

Moving to another server#

Copy the whole plugins/RPEngine/ folder with the plugin jar. If you want to copy only what matters:

Copy	Why
`content/`	Your packs
`config.yml`	Your settings
`blocks.json`	Which vanilla block each custom block is stored as. Without it, every custom block in the world turns into a different block
`model-numbers.json`	Below Minecraft 1.21.4, the numbers on custom items in inventories and the world. Lose it and items change into other items
`liquids.json`, `spawners.yml`	Your pools and the spawners made in game

Leave out output/ and cache/ (rebuilt on start) and unpacked-zips/. Leave out server-id too if the old server keeps running, so the two are counted separately.

Placed models are stored in the world itself, so they move with the world files.