Denoising

A path tracer starts with a noisy image, because each pixel only sees a few random light paths per frame. The Pathtracer's Method (Denoising page) decides how that noise is removed.

Method	Best for	Needs
Average	Still images and final renders. Perfectly clean, given time.	Nothing moving.
SVGF	Moving camera and objects, on any GPU.
OptiX	Moving scenes, with NVIDIA's AI denoiser.	Windows, an NVIDIA GPU.
DLSS	Moving scenes at high resolution, with NVIDIA's AI denoiser and upscaling.	Windows, an NVIDIA RTX GPU, the DLSS plugin.

Rays Per Pixel sets how many light paths each pixel traces per frame, for every method. More paths mean less noise to remove and a slower frame.

Average

Average adds up the frames. As long as nothing changes, the image gets cleaner with every frame, until it is as clean as you like. Any change (the camera, an object, a parameter) starts it over. Reset starts it over by hand.

Use it for stills: set up the shot with SVGF, then switch to Average and let it run.

SVGF

SVGF reuses the previous frames where they still fit and blurs the rest of the noise while keeping edges sharp. It works on any GPU and follows camera and object motion. Turn on Use Velocity when objects move.

Its settings trade smoothness against smearing and detail:

• Temporal Accumulation: Strength is how much of the previous frames is kept. Higher is smoother but slower to react, so moving things smear more. The three thresholds decide when a pixel's history no longer fits and is thrown away: when its depth, surface direction or surface colour changed too much.
• Spatial Filtering: Passes blurs the remaining noise, each pass reaching twice as far. Normal Sigma, Depth Sigma and Luma Sigma decide how strictly the blur stops at edges between surfaces, at depth steps and at changes in brightness.

If moving objects leave trails, lower Strength or tighten the thresholds. If the image is blotchy, raise Passes or Luma Sigma, or trace more Rays Per Pixel.

OptiX

OptiX is NVIDIA's AI denoiser. It has no settings of its own. It needs Windows and an NVIDIA GPU.

DLSS

DLSS Ray Reconstruction is NVIDIA's AI denoiser for path tracing. It removes noise, follows motion, and can render the image smaller and upscale it, which makes large outputs fast.

To use it:

1. Put DlssTOP.dll somewhere on your disk, for example next to your project.
2. Set Plugin Path to that file.
3. Set Method to DLSS.

Quality Preset sets how much smaller the Pathtracer renders than the output: DLAA renders at full size (no upscaling, the best quality); Quality, Balanced, Performance and Ultra Performance render at 1/1.5, 1/1.7, 1/2 and 1/3 of the output size. The output size is the panel's, or Resolution (see Camera, size and depth of field).

Turn on Use Velocity when objects move. The first frame after the plugin loads can take a moment.

Moving objects

SVGF, OptiX and DLSS all reuse information from previous frames. They always know how the camera moves; to know how objects move, turn on Use Velocity. Without it, moving objects can smear or leave trails.