Ray Tracing

A real-time rendering technique that simulates the physical behaviour of light rays, accurately calculating reflections, refractions, ambient occlusion (soft shadowing in crevices), global illumination (light bouncing off surfaces), and caustics (light focused through transparent materials), to produce photorealistic lighting that rasterisation-based rendering cannot replicate without baked approximations. Traditional rasterisation renders scenes by projecting geometry onto a flat plane and applying pre-calculated lighting, fast, but reliant on hacks for reflections (screen-space reflections break at screen edges) and soft shadows. Ray tracing casts simulated rays from the camera through each pixel, testing intersections with scene geometry and light sources, to compute true optical behaviour at the cost of significant GPU computation. NVIDIA introduced real-time ray tracing hardware acceleration in its Turing RTX series (2018); AMD followed with RDNA2 (2020), which also powers PlayStation 5 and Xbox Series X. Visually, ray tracing's most noticeable impact is on reflective surfaces (wet streets, windows, polished metal) and interior lighting (realistic bounce light in enclosed spaces). Most current-generation console games offer a 'Quality mode' (ray tracing enabled, 30fps target) vs 'Performance mode' (ray tracing disabled or reduced, 60fps target) split. DLSS, FSR, and XeSS upscaling are typically used to recover performance lost to ray tracing on PC.