API Reference

Two parallel folders, mirrored by topic where it makes sense:

• Editor — the toolbar widget and the settings file. This is where most users go.
• C++ — the runtime/editor subsystems and the settings UCLASS for projects extending the plugin from code.

The toolbar widget is documented separately as a first-class page — see Toolbar. It's the plugin's primary surface, not an API detail.

Page index

Concepts (shared)

A few facts are true regardless of which page you're reading.

What the override does

When the override is on and a class is selected, the plugin sets World->GetWorldSettings()->DefaultGameMode = OverrideClass on the live world at initialization time. The level asset itself is not modified. The original DefaultGameMode is captured before the swap so it can be restored on PIE end.

Where it applies

The override is editor-only by design. It runs in PIE and editor sessions; packaged and standalone builds always use the level's authored game mode.

Two subsystems cover the editor surface:

The editor GameInstance subsystem captures the world's authored DefaultGameMode before swapping in the override, then restores it on PIE end — so the override is fully transparent across PIE sessions.

Where it persists

Config/DefaultQuickGameModeOverride.ini. The settings object writes through to that file via SaveDefault() whenever the toolbar widget changes a value. Two keys:

[/Script/QuickGameModeOverride.QuickGameModeOverrideSettings]
bOverrideGameMode=True
OverrideGameModeClass=/Script/Engine.GameModeBase

OverrideGameModeClass is a TOptional<TSubclassOf<AGameModeBase>> under the hood — when unset, no key is written.

When it does not apply

• Packaged / standalone builds. The plugin is editor-only by design — the runtime module ships the settings object only, with no behavior of its own.
• Commandlets and the cook commandlet. The editor GameInstance subsystem refuses to spawn there (IsRunningCommandlet() || IsRunningCookCommandlet()), so cooking and headless tooling pick up the level's authored game mode.