Path traced, then denoised

What it does

pfx render --recipe traces a recipe through pfx's offline path tracer. It stages the same parts, materials, sky, sun and lights the live renderer draws, so a traced render and a live shot of one recipe show one scene.

It traces with hardware ray queries wherever the device offers them (Vulkan, DX12, Metal on Apple Silicon) and with its own BVH elsewhere, samples with Cycles' tabulated Sobol sequence, and stops each pixel once its noise is under the threshold. Past four point and spot lights it picks one light per bounce through a light tree ported from Cycles.

Then pfx-denoise, Intel Open Image Denoise 2.5.1's RT filter ported to wgpu compute, takes the traced colour with its albedo and normal and gives back the clean colour. Traced adaptively with Sobol and then denoised, a final takes 16 to 64 samples a pixel and a draft 6 to 12.

• Fewer samples, same noise

  On the neutral desk, Sobol reaches the noise PCG has at 256 samples a pixel with 101.4, and at 16 with 10.9.

• Many lights, one pick

  Through the light tree, a street of 128 lamps costs 6% more than one of 4. Light by light it cost 105% more. With four lights, both paths write the same bytes.

• Equal to OIDN

  On three neutral scenes the denoiser's output sits within 6.5e-5 of OIDN 2.5.1's own, 128.8 to 130.3 dB of PSNR in display space. The gap is float rounding.

• Long renders survive

  pfx job runs a long clip or render detached under a name and carries on from its last finished frame after a pause, a stop, a crash or a reboot. With --checkpoint, a crash inside a long frame loses at most the time since its last save.