Integration
Progressive camera path tracing.
Samples more paths toward area lights through glass and mirrors. Adds work per sample. Changing this resets the render.
May reduce indirect-light noise. Can increase glass noise. Changing this resets the render.
Solves caustic paths through smooth glass and mirrors to area lights. Adds work per sample. Changing this resets the render.
Reuses mesh-light reservoirs near the first scattering surface. May reduce direct-light noise; adds preparation work. Changing this resets the render.