AssetBundleBuilder

Command line tool for building Unity asset bundles for RimWorld mods. No repository cloning or Unity project setup required.

Quick Start

Recommended: Using Configuration File

Create a .assetbundler.toml file in your project:

[global]
unity_version = "2022.3.35f1"
bundle_name = "author.modName"
asset_directory = "Assets/"
output_directory = "AssetBundles/"
link_method = "junction"  # or "copy", "symlink", "hardlink"

# Note, if you are creating multiple assetbundles for a single mod, they need to have unique bundle_name's
[bundles.textures]
bundle_path = "author.modName"
bundle_name = "author.modName_textures"
filename = "resource_[bundle_name]_textures_[target]"
exclude_patterns = ["*.shader"]
targetless = true  # No platform suffix - creates single bundle for all platforms

[bundles.shaders] # specify `--target windows` (or mac or linux) when running assetbundlebuilder to build for each platform
bundle_path = "author.modName"
bundle_name = "author.modName_shaders"
filename = "resource_[bundle_name]_shaders_[target]"
include_patterns = ["*.shader"]
targetless = false  # Platform-specific - creates separate bundle per platform

Then build your bundles:

# Build a specific bundle, loads automatically from .assetbundler.toml
assetbundlebuilder --bundle-config textures

# Override settings from command line
assetbundlebuilder --bundle-config shaders --target windows

Installation

.NET Global Tool (Cross Platform)

# Install globally
dotnet tool install --global CryptikLemur.AssetBundleBuilder

# Use anywhere
assetbundlebuilder --config myproject.toml --bundle-config mybundle

Manual Installation

Download the appropriate executable for your platform from the Releases Page.

Configuration File Format

The TOML configuration file allows you to define multiple asset bundles with different settings:

Global Configuration

[global]
unity_version = "2022.3.35f1"                                     # Unity version to use
unity_hub_path = "/path/to/Unity/UnityHub.exe"                    # Or specify exact path
unity_editor_path = "/path/to/Unity/Editor/2022.3.35f1/Unity.exe" # Or specify exact path
output_directory = "AssetBundles"                                 # Default output directory
allowed_targets = ["windows", "linux"]                            # Restrict allowed targets
temp_project_path = "/tmp/unity"                                  # Custom temp directory
clean_temp_project = false                                        # Clean temp project after building. Disabled by default for caching
link_method = "copy"                                              # How to link assets: copy/symlink/hardlink/junction
exclude_patterns = ["*.meta", "*.tmp"]                            # Files to exclude
include_patterns = ["*.png", "*.wav"]                             # Files to include
targetless = true                                                 # Default for bundles: no platform suffix

Bundle Configuration

[bundles.mybundle]
description = "My custom asset bundle"
asset_directory = "Assets/MyBundle"
bundle_name = "author.mybundle"
output_directory = "1.6/AssetBundles"        # Override global output
allowed_targets = ["windows"]                # Only allow specific targets
filename = "resource_[bundle_name]_[target]" # Custom filename format
targetless = false                           # Platform-specific bundle (default: true)

# Bundle-specific patterns
exclude_patterns = ["*.backup"]
include_patterns = ["textures/*", "sounds/*"]

Advanced Examples

Multiple Bundles with Different Targets

Note, if you are creating multiple assetbundles for a single mod, they need to have unique bundle_name's

[global]
unity_version = "2022.3.35f1"
link_method = "junction"

[bundles.core]
asset_directory = "Core/Assets"
bundle_name = "author.core_mod"

[bundles.windows_only]
asset_directory = "WindowsAssets"
bundle_name = "author.myMod_windows"
build_targets = ["windows"]  # Only for Windows

[bundles.textures_hd]
asset_directory = "HD/Textures"
bundle_path = "author.myMod"
bundle_name = "author.myMod_textures_high"
exclude_patterns = ["*_low.png"]  # Exclude low-res versions

[bundles.textures_low]
asset_directory = "SD/Textures"
bundle_path = "author.myMod"
bundle_name = "mymod.low_textures"
exclude_patterns = ["*_high.png"]  # Exclude low-res versions

CI/CD Configuration

- name: Install AssetBundleBuilder
  run: dotnet tool install --global CryptikLemur.AssetBundleBuilder
  
- name: Build Asset Bundles
  run: assetbundlebuilder --ci

Features

Platform Support

• Build Targets: windows, mac, linux
• Build Restrictions: Use build_targets array to limit which platforms a bundle can be built for

Asset Management

• Link Methods: Choose how assets are linked to Unity project
  • copy: Copy files (safest, slower)
  • symlink: Symbolic links (fast, requires permissions)
  • hardlink: Hard links (fast, same volume only)
  • junction: Directory junctions (Windows, fast)
• Pattern Matching: Include/exclude files with glob patterns
• Custom Filenames: Use variables like [bundle_name], [target], [date]

Unity Integration

• Auto-Installation: Automatically installs Unity Hub and Editor if missing (Windows/macOS)
• Version Discovery: Finds Unity installations by version number
• Temp Project Caching: Reuses temp projects for faster rebuilds
• Custom Unity Paths: Override with specific Unity executable path

CI/CD Features

• CI Mode: Disables auto-installation for CI environments
• Non-Interactive: No prompts for automation
• Verbosity Control: Quiet mode for cleaner logs
• Clean Builds: Option to force fresh builds

Command Line Reference

Run assetbundlebuilder --help for full options list.

Troubleshooting

Unity Not Found

• Ensure Unity Hub is installed in standard location
• Or specify exact path in config: unity_path = "C:/Unity/2022.3.35f1/Editor/Unity.exe"

Permission Errors

• Windows: Use junction link method instead of symlink
• Linux/macOS: Ensure proper permissions or use copy method

Build Target Issues

• Check build_targets array in your config doesn't exclude your target
• Use --target CLI flag to specify build target

Project Stats

Support

• Issues: GitHub Issues
• RimWorld Modding: RimWorld Discord