Performance #

SSR is fundamentally fill-rate bound - cost scales with screen resolution and the number of march steps. Luminance is built to keep that cost reasonable, but it is a full-screen effect; budget for it like any post-process-class feature.

Biggest levers (cheapest first)

1. Use Backface Depth off - removes one full opaque geometry pass. Use the constant Thickness instead where thin-object accuracy isn't critical.
2. Lower Max Steps - the single biggest trace-cost dial. Thanks to Hi-Z you can often halve it with little visible change.
3. Lower Gap Fill - fewer mip taps in the composite.
4. Render scale - reducing URP render scale reduces SSR cost proportionally.