Path Tracing
Physically accurate light with random sampling
Also known as: Path tracer · Monte Carlo rendering · Unbiased rendering · Cycles path tracing · Unreal Path Tracer
Definition
Path tracing is a form of ray tracing that simulates light by following random paths from the camera through many bounces, and averaging many samples per pixel. It handles reflections, refraction, soft shadows, global illumination and caustics in one consistent method, and is the base of offline renderers such as Cycles and Arnold. Images start noisy and become cleaner as the samples increase, which is why denoising is so important.
In production
Use it for final stills and animation where quality matters, and expect longer render times than real-time engines. Samples, bounces and denoising are the main settings. Unreal Engine includes a Path Tracer as a reference renderer to check lighting and materials, but it is not for gameplay. Understanding path tracing helps you light by real-world logic, where bigger lights give softer light and noise.
Tools that use Path Tracing
See also
Ray Tracing
Simulating light by tracing rays
Denoising
Cleaning noise from low-sample renders
Eevee vs Cycles
Blender's real-time and path-traced renderers
Arnold Renderer
Maya's default path-traced renderer
Global Illumination
Light bouncing between surfaces
Noisy Renders in Blender Cycles
Grain and white dots in Cycles renders