Spellbreak Modkit

A visual .uasset editor and mod manager for Spellbreak Community Edition, built with Godot 4.

The editor targets Spellbreak's UE 4.22 asset layout and uses a fixed Spellbreak profile for packing, texture tools, tags, enums, and constants.

What's Included

The main project is spellbreak_uasset_editor/, a Godot 4 desktop app with a built-in mod manager, a full .uasset editor, and Spellbreak-specific profile data. Repository-level scripts and CI run the regression suite.

Everything is bundled inside the single binary:

UAssetAPI converter (pre-compiled .NET DLLs)
u4pak for packing mods into .pak files and extracting base-game sources
UE4-DDS-Tools + libtexconv for texture extraction/injection

Requirements

Python 3.10+ — required at runtime for mod packing, base-pak source generation, and texture operations

Windows: when installing Python, check "Add Python to PATH" on the first installer screen — it is unchecked by default.
.NET Runtime — required for UAssetAPI (asset parsing)
ImageMagick — required for texture export/import (DDS/TGA to PNG conversion)

Most Linux distros include it. On Windows, install from imagemagick.org and add to PATH.

Optional:

umodel (UE Viewer) — required for 3D mesh and animation preview (StaticMesh / SkeletalMesh / AnimSequence assets). Download a prebuilt binary or build from source. Set the path in Settings > umodel (3D Preview).
Godot 4.6+ — only if building the editor from source (no .NET support needed)

Setup

1. Get the editor

Prebuilt editor (recommended)

Go to the releases page, click on the latest version and download the file for your platform.

Release artifacts are packaged as linux.zip and win.zip.

OR: Build from source

git clone https://github.com/twdoor/spellbreak_modkit
cd spellbreak_modkit

Open spellbreak_uasset_editor/ in Godot 4.6+, then Project > Export > Linux/Windows. All dependencies (converter, u4pak, ue4_dds_tools) are bundled automatically.

2. Configure the editor

Launch the app, click Settings, and fill in:

Game directory — the folder used to locate the game executable and pak files. For Spellbreak, this install folder should contain g3/Content/Paks/.
Mods directory — the parent folder that contains your mod folders. Each direct child is treated as one mod and should mirror the game structure, for example Mods/MyMod/g3/Content/....
Launch command — optional, used by the Launch button
umodel path — optional, path to the umodel binary for 3D mesh and animation preview
Sources — extracted asset directories for reference. Use Generate from Pak to select a game .pak, choose an output folder, unpack it, and add the extracted folder as a source.

Settings are saved to config.json next to the executable.

GUI Editor

Mod Manager tab

The Mod Manager tab is pinned and always visible. It shows all mod folders found in your configured mods directory as a collapsible tree.

Action	Result
Left-click a mod	Expand / collapse it
Right-click a mod	Toggle enabled / disabled
Double-click a `.uasset`	Open it in the asset editor
Double-click any other file	Open with the configured editor or system default app
Open button on text/config files	Open `.txt`, `.cfg`, `.json`, `.ini`, `.md`, and similar files externally

Multi-select and clipboard:

Select files with Click, Ctrl+Click (toggle), or Shift+Click (range).

Shortcut	Action
`Ctrl+E`	Import files from sources
`Ctrl+C`	Copy selected files
`Ctrl+X`	Cut selected files
`Ctrl+V`	Paste into target mod (preserves `g3/Content/...` folder structure)
`Del / Ctrl+D`	Delete selected files or mods

Toolbar:

Button	Action
New Mod	Create a new mod folder
Settings	Open the Settings tab
Pack	Pack all enabled mods into a Spellbreak patch pak
Watch	Toggle auto-pack on file save
Launch	Launch the game

Sources

Sources are read-only reference folders used when importing files into a mod. They are expected to mirror the game's internal paths, for example:

SourceFolder/
└── g3/
    └── Content/
        └── ...

In Settings > Sources, Generate from Pak can build a source directly from a game package:

Select the base game .pak.
Select an output folder for extracted files.
The modkit unpacks the pak and adds the output folder to the configured sources.

When importing from sources in the Mod Manager, selecting a folder or file inside a mod opens the matching path inside the chosen source if it exists. If it does not exist, the file dialog falls back to the source root.

Asset editor tabs

Open .uasset or .json files via Ctrl+Space, drag-and-drop, or double-click from the mod list.

Keyboard shortcuts:

Shortcut	Action
`Ctrl+Space`	Open file
`Ctrl+S`	Save
`Ctrl+Q`	Close tab
`Ctrl+C / V / X`	Copy / Paste / Cut
`Del / Ctrl+D`	Delete selected item
`Ctrl+Z`	Undo
`Ctrl+A / F`	Previous / Next tab
`Esc`	Clear selection / cancel edit

What you can edit:

Export properties — structs, arrays, scalars, enums, text, object references, SoftObject paths
Array items — multi-select with Ctrl/Shift+click; copy/paste/delete supported
Import table — all fields editable inline; multi-select supported
Name map — add, edit, delete entries
DataTable rows — view, edit, copy/paste/delete rows
StringTable exports — namespace and all key/value entries

Texture support

When opening a texture .uasset (Texture2D, TextureCube, etc.), the detail panel shows:

Inline preview — the texture rendered at up to 512px wide with dimensions displayed
Export as PNG — save the texture to a PNG file
Import PNG — inject an edited PNG back into the .uasset (automatically handles BC1/BC3/BC5/BC7 format matching)

Texture operations require Python and ImageMagick to be installed and in PATH.

Audio support

When opening a SoundWave .uasset, the detail panel shows:

Inline playback — play, pause, stop controls with a seek slider and time display
Export as OGG — save the audio stream to an OGG Vorbis file
Import OGG — inject a new OGG file back into the .uasset (updates companion .uexp/.ubulk binary data and FByteBulkData headers)

Audio extraction and injection are implemented in pure GDScript — no external tools required.

3D Mesh support

When opening a StaticMesh or SkeletalMesh .uasset, the detail panel shows:

3D preview — interactive viewport with orbit, middle-drag pan, scroll zoom, and a resizable preview area
Auto-framing — camera automatically positions to fit the mesh on load
Animation preview — on SkeletalMesh assets, auto-find likely AnimSequence .uasset files or browse manually, then play, pause, loop, change speed, or scrub on the current mesh
Export as glTF — save the mesh to a glTF file

Mesh and animation preview require umodel to be installed and configured in Settings.

Spellbreak Profile

The editor uses a fixed JSON-backed Spellbreak profile. It tells the toolchain to target UE 4.22, use g3 as the content root, pack to g3/Content/Paks, and load Spellbreak enums, gameplay tags, and numeric constants.

Numeric Constants

The Spellbreak profile includes named constants for use in Int/Float property fields. Type an expression like sprint * 5 and it evaluates to the result. An autocomplete popup shows matching constants as you type.

How the Pak System Works

UE4 loads .pak files alphabetically. Files with the _P suffix are treated as patch paks that override matching paths in the base pak.

This modkit creates zzz_mods_P.pak inside Spellbreak's g3/Content/Paks/ folder.

zzz prefix ensures it loads last (after all base paks)
_P suffix marks it as a patch override
A .sig file is copied from an existing game pak (UE4 requires a signature file)
The base game is never modified

Your mod files must mirror Spellbreak's internal folder structure:

mods/
└── my_mod/
    └── g3/
        └── Content/
            └── Blueprints/
                └── GameModes/
                    ├── DA_BattleRoyale_Solo.uasset
                    └── DA_BattleRoyale_Solo.uexp

Always copy .uasset and .uexp together — they are a pair. If a .ubulk file also exists, copy that too.

Project Structure

spellbreak-modkit/
├── README.md
├── LICENSE
├── scripts/test.sh                 Parser check and regression test entry point
├── .github/workflows/ci.yml        GitHub Actions test workflow
└── spellbreak_uasset_editor/       Godot 4 app
    ├── main.gd / main.tscn         Entry point, tab bar, status bar
    ├── app_theme.gd                Centralized UI theme constants & helpers
    ├── property_row.gd             Inline property editor widget
    ├── converter/                  Bundled UAssetAPI DLLs (pre-compiled)
    ├── u4pak/                      Bundled u4pak (pak packing tool)
    ├── ue4_dds_tools/              Bundled UE4-DDS-Tools + libtexconv
    ├── game_profiles/              Spellbreak profile data
    │   └── spellbreak/             Profile, base enums, enums, tags, constants
    ├── uasset/                     Asset parsing & serialization
    │   ├── uasset_file.gd
    │   ├── uasset_export.gd
    │   ├── uasset_import.gd
    │   ├── uasset_property.gd
    │   ├── game_profile.gd         Spellbreak profile loader
    │   ├── ue4_enums.gd            Legacy wrapper (delegates to profile)
    │   └── spellbreak_tags.gd      Legacy wrapper (delegates to profile)
    ├── scenes/
    │   ├── process_utils.gd        Cross-platform subprocess helpers
    │   ├── asset_document.gd       Asset ownership, save point, undo/redo history
    │   ├── asset_edit_command.gd   Reversible editor mutation
    │   ├── asset_editor_context.gd Typed detail-view dependencies and actions
    │   ├── background_job_runner.gd Application-owned preview jobs and shutdown
    │   ├── uasset_tab.gd/tscn      Per-file editor tab
    │   ├── detail_panel_builder.gd
    │   ├── tree_manager.gd
    │   ├── selection_manager.gd
    │   ├── clipboard_manager.gd
    │   ├── texture_service.gd      Texture extraction/injection service
    │   ├── sound_service.gd        Audio extraction/injection service
    │   ├── mesh_service.gd         3D mesh/animation export via umodel
    │   ├── mesh_preview_material_loader.gd
    │   ├── md5_anim_loader.gd      MD5Anim parser and Godot animation builder
    │   ├── detail_items/           One class per detail-panel view
    │   │   ├── detail_item.gd      Base class with shared table helpers
    │   │   ├── property_detail.gd
    │   │   ├── export_detail.gd
    │   │   ├── texture_detail.gd   Texture preview & import/export
    │   │   ├── sound_detail.gd     Audio playback & import/export
    │   │   ├── mesh_detail.gd      3D mesh, material, and animation preview
    │   │   ├── exports_list_detail.gd
    │   │   ├── import_detail.gd
    │   │   ├── namemap_detail.gd
    │   │   ├── datatable_row_detail.gd
    │   │   └── stringtable_detail.gd
    │   └── mod_manager/
    │       ├── mod_manager_panel.gd
    │       ├── mod_settings_tab.gd  Settings UI
    │       ├── base_source_service.gd
    │       ├── config_manager.gd
    │       ├── mod_state_manager.gd
    │       ├── mod_discovery.gd
    │       ├── file_watcher.gd
    │       ├── file_utils.gd
    │       └── packing_service.gd
    ├── guide/                      GUIDE action resources (remappable keybinds)
    ├── tests/test_core.gd          Core regression tests
    └── addons/                     GUIDE input framework

Development

Run the parser check and regression suite with Godot 4.6.3+:

./scripts/test.sh

The suite covers package-index remapping, undo restoration, transactional file replacement, subprocess argument handling, and pak creation/failure recovery.

Credits

UAssetAPI by atenfyr — UE4 asset serialization (bundled)
u4pak by panzi — UE4 pak archive tool (bundled)
UE4-DDS-Tools by matyalatte — UE4 texture extraction/injection (bundled)
Texconv-Custom-DLL by matyalatte — Cross-platform texture format converter (bundled as libtexconv)
umodel / UE Viewer by Gildor — UE4 mesh viewer/exporter (optional, user-installed)
G.U.I.D.E by Jan Thomä — Input mapping framework (bundled)

Name		Name	Last commit message	Last commit date
Latest commit History 27 Commits
release_notes		release_notes
scripts		scripts
spellbreak_uasset_editor		spellbreak_uasset_editor
.gitattributes		.gitattributes
.gitignore		.gitignore
ArcaneTrickster_ChrSK.glb		ArcaneTrickster_ChrSK.glb
CHANGELOG.md		CHANGELOG.md
LICENSE		LICENSE
README.md		README.md
TODO.md		TODO.md

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Spellbreak Modkit

What's Included

Requirements

Setup

1. Get the editor

Prebuilt editor (recommended)

OR: Build from source

2. Configure the editor

GUI Editor

Mod Manager tab

Sources

Asset editor tabs

Texture support

Audio support

3D Mesh support

Spellbreak Profile

Numeric Constants

How the Pak System Works

Project Structure

Development

Credits

About

Releases

Packages

Contributors

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Repository files navigation

Spellbreak Modkit

What's Included

Requirements

Setup

1. Get the editor

Prebuilt editor (recommended)

OR: Build from source

2. Configure the editor

GUI Editor

Mod Manager tab

Sources

Asset editor tabs

Texture support

Audio support

3D Mesh support

Spellbreak Profile

Numeric Constants

How the Pak System Works

Project Structure

Development

Credits

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