Install UndertaleModTool

About UndertaleModTool

The most complete tool for modding, decompiling and unpacking Undertale (and other GameMaker games!) Main Features: - Can read every single byte from the data file for latest versions of Undertale, Deltarune, and most other GameMaker games, and then recreate a byte-for-byte exact copy from the decoded data. - Properly handles all of the pointers in the file so that if you add/remove stuff, make things longer/shorter, move them around, etc., the file format won't break. - An editor which lets you change (almost) eve...

What's new in 0.9.0.0

This is the 0.9.0.0 UndertaleModTool release, for 64-bit Windows. Downloads can be found at the bottom of this release. ("UTMT_CLI" is the command-line interface version with no GUI, supported for Windows, Ubuntu, and macOS.) Changelog Added - Added an optional project system, designed to be a more resilient and collaborative method of creating mods. - Has the ability to export and reimport assets of many types, in a manner that is friendly to source control such as Git. This both makes collaboration much easier and allows easy version history. - Similar to the now-obsolete profile mode, GML edits are retained in plaintext, meaning that comments and formatting are preserved. External editors can also be used on all asset types, including code. - Theoretically can be used as a mod installation process, with the ability to manage external data files, create backups when installing, apply file patches (using BPS), verify game versions, and execute scripts. - In the GUI, asset changes are detected when you change them in their respective editors, which marks them to be exported when you later save the project. This works for the majority of supported assets, but some features are only supported via manual editing of JSON files, such as the main project file itself, and general info (such as changing the game window title). - The system is not yet feature-complete, and has room to grow to reach its full potential - see #2350. Currently, it is only accessible from the GUI and from the library itself, although it should have no issue being extended to the CLI in the future. - Adde...

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