UBT (Unity Bundle Tool)

A powerful, user-friendly command-line tool to extract and repack Unity asset bundles. Built with Python and UnityPy.

Developer: minhmc2007

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Installation

Install the tool directly from PyPI:

pip install unity-bundle-tool

Usage

Once installed, you can use the ubt command from your terminal.

Extract a Bundle

ubt extract path/to/your/asset.bundle path/to/output_folder/

This will create:

output_folder/
├── manifest.json           # Asset tracking manifest
├── Textures/              # PNG files from Texture2D/Sprite assets
├── TextAssets/            # TXT/bytes files from TextAsset objects
├── MonoBehaviours_JSON/   # JSON files from MonoBehaviour typetrees
├── MonoBehaviours_DAT/    # Raw binary data from MonoBehaviours
├── AudioClips/            # WAV or raw audio files
└── OtherAssets/           # Generic binary data from other asset types

Repack a Bundle

After modifying files, repack them into a new bundle:

ubt repack path/to/output_folder/ path/to/new_repacked.bundle

Important: The input directory must contain the manifest.json file created during extraction. The original bundle file referenced in the manifest must still exist and be accessible.

Features

• Extract Unity bundle files to organized directory structure
• Support for multiple asset types:
  • Textures (Texture2D, Sprite) → PNG files
  • Text Assets → TXT/bytes files
  • MonoBehaviours → JSON (typetree) or DAT (raw binary)
  • Audio Clips → WAV or raw audio data
  • Generic Assets → Raw binary data
• Repack modified assets back into Unity bundle format
• Automatic file sanitization and organization
• Detailed manifest tracking for reliable repacking

Asset Type Support

Asset Type	Extraction Format	Repacking Support
Texture2D/Sprite	PNG	✅ Yes
TextAsset	TXT/bytes	✅ Yes
MonoBehaviour (with typetree)	JSON	✅ Yes
MonoBehaviour (raw)	DAT binary	⚠️ Limited
AudioClip	WAV/raw audio	⚠️ Limited
Other types	Raw binary	⚠️ Limited

Workflow

1. Extract a bundle to examine and modify assets
2. Modify the extracted files as needed:
   • Edit PNG images in image editors
   • Modify text files
   • Edit JSON files for MonoBehaviour data
3. Repack the modified assets into a new bundle

Important Notes

• Keep the original bundle file: Repacking requires the original bundle as a template
• Preserve file structure: Don't move files between the organized subdirectories
• Manifest dependency: The manifest.json file is essential for repacking
• Binary compatibility: Some asset modifications may not work depending on Unity version and asset complexity
• Backup your files: Always keep backups of original bundles before modification

Error Handling

The script includes comprehensive error handling for:

• Corrupted or protected bundle files
• Missing dependencies
• Invalid file paths
• Asset processing failures
• Repacking inconsistencies

Limitations

• MonoBehaviour repacking from raw DAT files has limited reliability
• AudioClip repacking may not preserve original compression formats
• Some Unity-specific asset formats may not be fully supported
• Protected or encrypted bundles cannot be processed

Command Line Help

ubt --help
ubt extract --help
ubt repack --help

License

This project is licensed under the GPL 3 License.