KismetKompiler is a powerful decompiler and compiler tool designed specifically for Unreal Engine 4 blueprints. It provides support for decompiling most blueprints into a C#-like syntax and offers the ability to compile the decompiled code using a custom script format called KisMetScript (.kms).
- Decompilation: KismetKompiler can decompile most blueprints, converting them into a C#-like syntax. However, please note that not all blueprint constructs are currently supported.
- Verification: The tool automatically verifies the equality of the decompiled code to ensure accuracy during the decompilation process. This can be toggled off however.
- Compilation: KismetKompiler supports compiling the decompiled blueprint code using the .kms script format (KisMetScript).
- Editing: The tool provides limited editing functionality for decompiled code, allowing you to modify existing logic, add new logic, add new variables and functions, and import new library functions. However, certain actions, such as creating a class from scratch or modifying existing variable or function definitions, are not yet supported.
- Error Detection: The compiler includes limited error detection capabilities. However, please note that error messages might not be as descriptive as they should be in some cases.
- Compatibility: KismetKompiler has been primarily tested with Unreal Engine 4.23 assets, specifically those used in Shin Megami Tensei V.
To use KismetKompiler, follow these steps:
- Download the latest release.
- Unzip the contents of the zip to a folder
The general usage of KismetKompiler is as follows:
KismetKompiler <command> [options]
Displays more information on a specific command.
KismetKompiler help <command>
Compiles a script into a new or existing blueprint asset.
-i, --input: (Required) Path to a .kms file containing the script to compile.-o, --output: Path to the output .uasset file. If not specified, a new blueprint asset will be created with a default name.--asset: Path to an existing .uasset file. If specified, the script will be compiled into this existing blueprint asset.-v, --version: (Optional) Unreal Engine version (e.g., 4.23).-f, --overwrite: (Optional) Overwrite existing files.--usmap: (Optional) Path to a .usmap file.--global: (Optional) Path to a global.ucas/utoc file. Required if IO store is used (eg. no uexp, usmap required)--help: Display the help screen.
Example:
KismetKompiler compile -v 4.27 -i BP_BtlCalc.kms -o BP_BtlCalc_edit.uasset --asset BP_BtlCalc.uasset
Decompiles a blueprint asset into a .kms file.
-i, --input: (Required) Path to an input .uasset file containing the blueprint asset to decompile or a folder containing blueprint assets to decompile.-o, --output: Path to the output .kms file. If not specified, a default name will be used. Not applicable if the input as a folder.--no-verify: Skip verifying the equality of the decompiled code.-v, --version: (Optional) Unreal Engine version (e.g., 4.23).-f, --overwrite: (Optional) Overwrite existing files.--usmap: (Optional) Path to a .usmap file.--global: (Optional) Path to a global.ucas/utoc file. Required if IO store is used (eg. no uexp, usmap required)--help: Display the help screen.
Example:
KismetKompiler decompile -v 4.27 -i BP_BtlCalc.uasset
While KismetKompiler provides significant functionality for decompiling and compiling blueprints, it has a few limitations:
- Not all blueprint constructs are currently supported during decompilation, and will be expressed using so called intrinsic functions (prefixed with EX_...).
- The editing functionality is limited and does not support certain operations, such as creating a class from scratch or modifying existing variable or function definitions.
- Error messages may not be as descriptive as desired due to limited error detection capabilities.
Moreover, as the code compiles down to blueprint expressions, some things you would expect to work in other programming languages don't work, or don't work yet due to insufficient knowledge about how the code is executed:
- Reusing an interface object is not possible (eg. GetBPAICommand in SMTV needs to be called before every usage of the interface, otherwise the game will freeze)
- Returning values from local script functions does not seem to be possible. Only out parameters can be used.
Contributions to KismetKompiler are highly appreciated. If you encounter any issues, have feature requests, or would like to contribute to the project, please feel free to do so. You can submit bug reports, feature requests, or pull requests through the GitHub repository.
This project relies on the following third-party dependencies:
- UAssetAPI by atenfyr: A library that provides functionality for working with Unreal Engine .uasset files. This project would not be possible without it. GitHub repository - MIT License
KismetKompiler is released under the MIT License. See the LICENSE file for more details.