Getting started
You need:
- Thief: Deadly Shadows from Steam, installed. T3SDK supports the Steam release (patch 1.1); other releases are detected and left alone (see Unsupported builds).
- Windows 10 or 11, 64-bit.
Nothing else: the launcher brings its own copy of the tools, the SDK and Python. Godot is only needed to edit maps.
Download the launcher
Take one of these from the latest release:
| File | What it is |
|---|---|
T3SDK-Launcher_<version>_x64-setup.exe | The installer. It installs for your user only and needs no admin rights. |
T3SDK-Launcher_<version>_portable.zip | The same files, to unzip into any folder and run from there. |
The installer is not code-signed, so Windows may warn about an unknown publisher. Choose More info, then Run anyway.
First run
The first time it starts, the launcher opens its setup screen. It looks for each of these by itself and checks what it finds:
| What | Where it looks | What it checks |
|---|---|---|
| The game | the game installer's registry entry, your Steam libraries, T3_GAME_DIR | that T3Main.exe is the supported Steam build (by its SHA-1) |
| The T3SDK folder | the copy that comes with the launcher | that the tools are there |
| Python | the copy that comes with the launcher, then others on your PC | Python 3.10 or newer |
| Godot | GODOT, PATH, common install folders | Godot 4.7 or newer (optional: map editing only) |
When the entries show OK, click Continue. If the game is not found, pick its folder: the one that holds the System and Content folders. You can change every path later under Settings.
A game that fails the check still starts, but T3SDK leaves it alone. The Play page shows whether your build is supported.
Updates
The launcher checks the project's GitHub Releases for a newer version and offers to install it. You can also download a newer release yourself and install it over the old one. Each release lists its changes on the Releases page.
Next
- Playing with T3SDK: install the SDK, and what its fixes do.
- Installing mods: packages, the mod browser, load order and profiles.
- Save backups: do this before you try mods.
- Settings explained: every setting T3SDK and the launcher have, and when to change it.
- Other mods and tools, the FAQ and the glossary.