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 0.9.1.1

This is the 0.9.1.1 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 Note: This is a patch release. To see the changes in major release 0.9.0.0, click here. To see the changes in minor release 0.9.1.0, click here. Changed - Dumping all code from the CLI no longer exports sub-function code entries, which was pointless and could result in filename length errors. Performance has been optimized and parallelized, as well. - Missing mb_side1 and mb_side2 mouse button constants are now included, usable in GameMaker 2.3.3 games and above. - Missing room asset resolutions for scr_84_add_menu_item in older DELTARUNE chapters added by @vrad-exe in #2411. - Some miscellaneous dependencies updated. Fixed - Fixed Debug.csx not supporting DELTARUNE Chapter 5 by @break-core in #2409. - Fixed ExportSpritesAsGIF.csx failing on some modern GameMaker games with unused asset removal enabled. - Fixed prefab-generated scripts compiling in a way that would cause function resolution errors (only a mitigation for now, full support may come later). - Fixed compilation warnings of UndertaleModLib/UndertaleModTool due to PropertyChanged.Fody not being a private dependency. - Fixed detection of Spine sprite format changes introduced in GameMaker 2023.1, so that it no longer breaks on 2022 LTS games. New Contributors - @break-core made their first contribution in #2409 - @vrad-exe made their first contribution in #2411 Full Changelog: 0.9.1...

Read release notes

Version history