Settings explained

Every setting T3SDK and the launcher have, in plain terms: what it does, its default, and when you'd change it. For how the fixes work under the hood, see SDK settings and tools and Engine internals.

Changing settings

Two ways to change System\T3SDK.ini:

• The launcher's SDK settings page shows every key as a toggle, a key box, or a text field. Its list, order and descriptions come straight from the SDK's own T3SDK.ini, so a setting the SDK adds later shows up here without a launcher update. Save writes your changes into the file in place, keeping its comments; Revert discards them. If the file is missing (for example after copying just dinput8.dll in by hand), the page offers to create one with the defaults.
• Edit System\T3SDK.ini directly in a text editor. 1 turns a setting on, 0 off; a few (DumpObjectsKey, MaxFPS, CursorScale) take a number instead.

Either way, changes take effect the next time the game starts: T3SDK reads the file once, at start-up, not while the game is running.

The launcher shows the [T3SDK] section as "General"; [Fixes] and [Display] keep their names. This page is about what each setting does; Playing with T3SDK covers installing and removing the SDK itself, and Installing mods covers the mod loader.

T3SDK's own settings

General

The [T3SDK] section: the log, and a couple of things for mod authors.

Setting	Default	What it does
Console	off	Opens a console window that mirrors T3SDK.log live, so you can watch it without leaving the game. Handy while reporting a problem or testing a mod; otherwise it's one more window on your desktop.
EngineLog	on	Copies the game's own log lines into T3SDK.log alongside T3SDK's own. Turn it off for a shorter, T3SDK-only log.
DumpObjectsKey	0x79 (F10)	While the game has focus, this key writes every live engine object to T3SDK_objects.txt. It's for mod authors inspecting the object table; set it to 0 to turn the hotkey off, for example if a mod binds F10 to something else.
MenuVersionLabel	on	Adds [Modded - T3SDK <version>] to the main menu's version line, so you can see at a glance that T3SDK is active. Turn it off for an unmarked main menu.
MenuInputTrace	off	Logs main-menu and pop-up input events. A diagnostic switch for UI modding; leave it off unless someone helping with a menu problem asks you to turn it on.

Fixes

Setting	Default	What it does
SkipIntros	on	Skips the Eidos, Ion Storm, copyright, nVidia and EAX logo movies at start-up, so the main menu appears sooner. Turn it off to see them, or to check the game's original start-up sequence.

Display

The biggest section, and the one most worth reading. A borderless window is what most of the others build on.

Setting	Default	What it does
NativeResolutions	on	Offers your monitor's own resolutions in Options > Audio/Video, with your native resolution as the top entry. Without it, the game only ever offers five fixed resolutions, 640x480 up to 1600x1200.
Borderless	on	Runs the game in a window with no border or title bar, sized to cover the monitor, instead of exclusive fullscreen. This is what lets you alt-tab, use other monitors and take screenshots with any normal tool, and it's what makes the VSynch-in-a-window fix, the scaled cursor and the level-change curtain (below, and see Troubleshooting) possible. Turn it off to go back to exclusive fullscreen; you'd lose all of those along with it.
WidescreenUI	on	Lays menus and the HUD out for your screen's own aspect ratio, instead of stretching the game's 4:3 layout to fill it: menus stay centred, and the HUD moves out to the screen edges. Turn it off to compare against the original stretched layout.
UILayoutTrace	off	Logs where every UI window is placed, once. For UI modding, not for play.
PauseInBackground	off	With the default (off), a borderless game keeps running when you switch to another window; set it to 1 to bring back the game's own habit of pausing the moment it loses focus. Either way, pausing yourself before you alt-tab away is the safer habit.
SmoothFrames	on	Moves the game world every frame. Left off, the engine's own clock only advances the world once 10 ms have passed, so above 100 fps the world and the camera move on only every second or third frame, which looks choppy however high the frame rate. Not yet tried in the actual game: if you notice odd behaviour in fast-moving things (physics, jumping, mantling, rope arrows) above 100 fps, turn it off and report it.
MaxFPS	0 (no limit)	Caps the frame rate. Uncapped, the main menu has been measured between 200 and about 1,255 fps on one test machine, which is more work for your GPU than the screen can show. With VSynch on (below), the frame rate already follows your monitor; a cap is for when VSynch is off. Not yet tried in the actual game.
CursorScale	0 (grows with screen height)	Sets the size of the menu cursor in the borderless window. 0 scales it with the screen (1x at 768 lines); a fixed number such as 1.5 overrides that.
FrameStats	off	Logs frames per second and the time spent presenting a frame, every 10 seconds. For reporting a performance problem, or curiosity.

The game's own Options

These live in the game's own Options > Audio/Video screen, not in T3SDK.ini, but T3SDK changes what some of them do:

• Resolution. With NativeResolutions on (the default), this list is your monitor's own modes, with your native resolution as the highest entry. It's still the game's own option; T3SDK only replaces the five entries it would otherwise offer.
• VSynch. On by default in the game itself. In the borderless window, T3SDK now makes it present once per monitor refresh too, through Direct3D 8's COPY_VSYNC swap effect — the same pacing exclusive fullscreen always had. This doesn't apply together with MultiSampling (below); with both on, the window presents as fast as it can, unpaced. Not yet tried in the actual game.
• MultiSampling. The game's anti-aliasing option. Switching it on turns off the VSynch-in-a-window pacing described above, for that combination.
• Brightness. T3SDK doesn't change what this does.

The launcher's own settings

Separate from T3SDK.ini: these live in your own user profile (%APPDATA%\org.t3sdk.launcher\launcher.json), not the game folder, and only affect the launcher itself.

On the Settings page:

• Paths: the game folder, the T3SDK folder (the launcher's bundled copy, or a checkout), Python, Godot, the Godot project folder (default: build\assets\godot inside the T3SDK folder) and the saves folder (default: found automatically; see Save backups). Search again re-detects all of them; each field also shows what it checked, for example that T3Main.exe is the supported build.
• Mod index: the URL the Mods page's browser reads. Leave it empty to use the T3SDK project's own index (https://veradictus.github.io/Thief3-Decomp/modindex/index.json).
• Updates: Check for updates at start-up (at most once a day) and Check now. A build made without the update key — a development build, or one built from a fork — says so here instead, and links to the releases page. See the FAQ for why the installer itself still gets a Windows warning even when this works.
• Collect logs and Report a problem (also on the Play page): see Troubleshooting.
• Run setup again re-opens the first-run setup screen, so you can re-check or change every path.

The Saves page has one setting of its own: Back up before starting the game (off by default) makes a save backup, skipping it when nothing has changed, every time you click Play. See Save backups.