Ray tracing

Ray tracing calculates lighting by tracing the paths of rays of light as they travel through a scene, hit surfaces, bounce, reflect and cast shadows. The result can look strikingly realistic: accurate reflections in puddles and windows, soft shadows, and light that spills naturally from bright surfaces onto nearby ones.

The technique has long been used for animated films and visual effects, where each frame can take a long time to produce. Doing it in real time, many times per second, is far more demanding, which is why it has only become common in games relatively recently, with dedicated hardware in modern graphics cards and consoles.

How games use it

Most games combine ray tracing with traditional techniques, applying it to specific effects such as reflections, shadows or global illumination (indirect light bouncing around a room). Path tracing is a more complete form that traces light for nearly everything in the scene; it looks impressive but is extremely demanding and mostly found on high-end PCs.

The cost

Ray tracing usually reduces frame rate, sometimes substantially. That is why console games often include it in quality modes and leave it out of performance modes, and why PC players commonly pair it with upscaling technologies that recover some of the lost performance. Whether it is worth turning on depends on the game and on your preferences: in some games the visual difference is dramatic; in others it is subtle.

Should you use it?

For slower, atmospheric games, many players enjoy turning ray tracing on. For fast competitive games, most prefer a higher frame rate instead. Try a few minutes in each mode and pick what you notice most. There is no need to buy new hardware just for ray tracing; plenty of excellent games look great without it.