Denoising
Cleaning noise from low-sample renders
Also known as: Denoiser · OpenImageDenoise · OptiX denoiser · Render denoise · AI denoiser
Definition
Denoising removes the grain from images made with few samples, such as path-traced renders and ray traced games. A denoiser studies the noisy image, often with extra information such as normals, albedo and depth, and reconstructs a smooth result. Common ones are Intel Open Image Denoise and NVIDIA OptiX, with AI-based versions in game technologies. It makes a render with far fewer samples usable, saving a lot of time.
In production
Turn it on for Cycles, Arnold and Toolbag renders, and compare it at full size, since denoisers can smear fine detail, text and patterns. Give it clean extra passes if your renderer supports them. Denoising works best when the lighting is good, so improve large light sources first. In games, denoisers are built into the ray tracing effects, and artifacts show as smeared or lagging light.
Tools that use Denoising
See also
Path Tracing
Physically accurate light with random sampling
Ray Tracing
Simulating light by tracing rays
Noisy Renders in Blender Cycles
Grain and white dots in Cycles renders
DLSS / FSR
AI / spatial upscaling for higher framerates
Render Passes (AOVs)
Separate layers of a render for compositing
Arnold Renderer
Maya's default path-traced renderer