Porting Guide: Fabric → NeoForge

This document explains the differences between the original Fabric version (Apace100/origins) and the NeoForge rewrite (IAFEnvoy/Origins-NeoForge). Use it to convert existing data packs, add-ons, or documentation from the Fabric version to the NeoForge version.

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Data Path Changes

All JSON files moved from custom paths to Vanilla DataPack Registry paths.

Content	Fabric Path	NeoForge Path
Origin	data/<ns>/origins/	data/<ns>/origins/origin/
Power	data/<ns>/powers/	data/<ns>/origins/power/
Layer	data/<ns>/origin_layers/	data/<ns>/origins/layer/
Badge	(not in Fabric)	data/<ns>/origins/badge/
Global Power Set	data/<ns>/global_powers/	❌ Not yet implemented

Action: Move files and add registry subfolder (origin/, power/, layer/, badge/).

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Origin JSON Changes

Field	Status	Notes
name	❌ Removed	Use translation key origin.<ns>.<path>.name
description	❌ Removed	Use translation key origin.<ns>.<path>.description
loading_priority	❌ Removed	Data packs now override by priority naturally
powers	Changed	Now supports #tag references. Prefer #tag over listing individual power IDs
icon	Changed	From Item+Damage+NBT to {"id": "minecraft:feather"}
order	Changed	Default changed from 0 to Integer.MAX_VALUE
impact	Same	0=None, 1=Low, 2=Medium, 3=High
unchoosable	Same
upgrades	Same

Action: Remove name/description/loading_priority from all origin JSONs. Add name/description via language files instead. Update icon to the new {"id": "..."} format. Use #tag references in powers instead of listing each power ID individually whenever possible.

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Layer JSON Changes

Field	Status	Notes
replace	❌ Removed	Use data pack override behavior
name	❌ Removed	Use translation key layer.<ns>.<path>.name
missing_name	❌ Removed	Not needed
missing_description	❌ Removed	Not needed
origins	Changed	Now supports #tag references. Prefer #tag over listing individual origin IDs
gui_title.choose_origin	Renamed	Was choose_origin (top-level); now nested under gui_title
gui_title.view_origin	Renamed	Was view_origin (top-level); now nested under gui_title
order	Same
enabled	Same
allow_random	Same
hidden	Same
auto_choose	New	Auto-choose if only one origin is available
default_origin	New	Default origin for new players
allow_random_unchoosable	New
exclude_random	New

Action: Move choose_origin/view_origin under gui_title. Remove replace/name/missing_name/missing_description. Use #tag references in origins instead of listing each origin ID individually whenever possible.

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Power JSON Changes

Field	Status	Notes
hidden	Same
condition	Same	Entity Condition
loading_priority	Same
badges	Same	Supports inline {badge} objects
type	Same	Power type ID

Action: Power JSONs are mostly compatible. Translate power names/descriptions via power.<ns>.<path>.name / .description keys.

origins:multiple — Split into individual files

Fabric's origins:multiple power type (which bundled several sub-powers into one JSON file) does not exist in NeoForge. Each sub-power must be extracted into its own standalone power JSON file.

Fabric	NeoForge
One multiple JSON with nested sub-powers	One file per power, referenced individually
"type": "origins:multiple" with "powers": [...]	Each power gets its own file in data/<ns>/origins/power/

Action: For each entry in the powers list of an origins:multiple, create a separate power JSON file. Reference all the split power IDs in the origin's powers field or a power #tag.

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Condition Type Changes

origins:attacker — Moved to BiEntity & Damage conditions

In Fabric, origins:attacker was an entity condition used inside bientity conditions. In NeoForge:

Registry	Type ID	Category	Field
origins:bientity_condition	origins:attacker	[Bi-entity Condition]	Checks if the actor attacked the target
origins:damage_condition	origins:attacker	[Damage Condition]	Checks the attacker via entity_condition

Action: Replace nested entity-condition attacker with the corresponding BiEntity/Damage condition variant.

origins:attack_target

Same as above: in Fabric it was nested inside bientity conditions. In NeoForge it's a direct BiEntity condition (origins:attack_target) checking if the actor is targeting the target.

Registry	Type ID	Category
origins:bientity_condition	origins:attack_target	[Bi-entity Condition]

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Removed Condition Types

Fabric Type	Status in NeoForge	Note
origins:command	❌ Removed
origins:entity_group	❌ Removed	1.21.1 no longer has entity groups, use origins:in_tag instead
origins:category (biome)	❌ Removed	1.21.1 no longer has biome categories, use origins:in_tag instead
origins:high_humidity (biome)	❌ Removed	1.21.1 no longer has humidity conditions, use origins:in_tag instead`
origins:owner (bientity)	❌ Removed	Will be added later

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Not Yet Implemented

These features existed in Fabric but are not yet available in NeoForge:

Feature	Status
origins:chose_origin advancement trigger	❌ Not yet implemented
/resource command	❌ Not yet implemented
origins:origin predicate	❌ Not yet implemented
apoli:power predicate	❌ Not yet implemented
Global Power Set	❌ Not yet implemented
Conditioned Origins in Layers	❌ Not yet implemented
origins:edible_item power type	❌ Not yet implemented
origins:modify_enchantment_level power type	❌ Not yet implemented

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New Features

Feature	Notes
DataPack Registry System	All Origins JSON uses Vanilla's datapack registry
Power Tags	Reference #tag in origin powers and layer origins
Default Origin	Layer field: assign default on join
Badge Registry	Badges use Vanilla registry at origins:badge
Inline Badge Definitions	badges in powers can take inline {badge} objects
ColorSettings	red/green/blue/alpha floats + single color hex integer

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Key API Differences

Fabric (Apoli) API	NeoForge API
PowerTypeRegistry	PowerRegistries.POWER_KEY via Registry
OriginsRegistry	OriginRegistries.ORIGIN_KEY
OriginLayerRegistry	LayerRegistries.LAYER_KEY
OriginsAPI	OriginDataHolder.get(entity) as attachment
PowerType interface	Power abstract class with MapCodec
PowerHolderComponent	OriginDataHolder (NeoForge attachment)
PowerTypeRegistry#register	BuiltInRegistries + DeferredRegister pattern

Action: For Java add-ons targeting NeoForge, port from Apoli's PowerTypeRegistry to NeoForge's DeferredRegister<MapCodec<? extends Power>> pattern.

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AI Porting Prompt

When converting Fabric Origins data packs to NeoForge, use this prompt:

You are porting an Origins Fabric data pack to the NeoForge version (IAFEnvoy/Origins-NeoForge).

Changes to apply:
1. Move all JSON files to datapack registry paths:
   - origin JSONs: data/<ns>/origins/ → data/<ns>/origins/origin/
   - power JSONs: data/<ns>/powers/ → data/<ns>/origins/power/
   - layer JSONs: data/<ns>/origin_layers/ → data/<ns>/origins/layer/
2. Remove from Origin JSONs: name, description, loading_priority.
   Add translations to language file: "origin.<ns>.<id>.name" and ".description".
3. Remove from Layer JSONs: replace, name, missing_name, missing_description.
   Move choose_origin/view_origin under a new "gui_title" object.
   Add translations: "layer.<ns>.<id>.name".
   Use #tag references in origins instead of listing individual origin IDs.
4. Update icon format: old "item"/"damage"/"nbt" → new {"id": "minecraft:..."}
   Use #tag references in powers instead of listing individual power IDs.
5. Split any origins:multiple powers into individual power JSON files.
6. Replace removed condition types (command, entity_group, category, high_humidity, owner) with equivalent alternatives or JS scripts.
7. origins:attacker and origins:attack_target are now BiEntity conditions directly — no longer nested entity conditions inside bientity conditions.
8. Do NOT nest comparison/compare_to fields — they remain as flat top-level keys.
9. Check the porting guide at porting.md for the full list of differences.