screenSpaceGI

Runtime control of the scene's screen-space bounced light — the surface a quality slider, a cutscene, or a debug toggle drives.

local screenSpaceGI = require("@builtin::systems.screenSpaceGI.screenSpaceGI")

screenSpaceGI.set({ intensity = 1.0, radius = 2.0, samples = 12 })
screenSpaceGI.get()      -- the settings in force
screenSpaceGI.active()   -- whether the gather is running this frame
screenSpaceGI.clear()    -- off, keeping the rest authored

set creates the render feature the first time the effect is wanted and releases it when intensity reaches 0, so a scene that never enables it pays nothing.

For a scene that should simply have bounced light, add the ScreenSpaceGI component instead — it persists with the scene.