Path tracer denoiser - Set intensity?

Hi all,

I am looking to reduce the effect of the open image denoiser on path traced render results. Neither the post process volume nor the movie render queue settings seem to offer a way to control denoising strength through their UI. Is there a way to do this hidden in console commands or maybe through workarounds?

The denoiser works great, but it tends to be aggressive, resulting in overly smooth images. I’d love to keep some of the grain from the path traced image. Something like an opacity setting for the denoised result would already do.

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I too would love to see this, a simple 0-1 value global blend or strength would be great. The OpenImage implementation as it stands now is almost always far too heavy-handed to be used for final output frames. It would be a huge quality of life improvement if we could use it for times when de-noising in post isn’t in scope

Thanks for joining in. Glad to hear I am not alone :slight_smile:

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I have the same problem. In my observation, the denoiser is less aggressive the higher a sample count you use, which I find useful as it facilitates quick, cheap test renders followed up by more detailed, extensive ones.

I’m planning on righting a developer feedback post asking Epic to address their denoiser. Not just with using Intel’s OpenImage AI, but perhaps encouraging the creation of more third-party plugins, which they now support. In particular, something like Nvidia’s SVGF (which Epic themselves opted for in Fortnite over their own denoiser). I’ve played around with NVRTX and other pieces of software that use it, and the new denoisers are transformational.

Moreover, I believe path-tracing could use a few structural overhauls, in addition to the amazing content and perf updates we’ve been receiving. The industry is gradually moving in the direction of real-time path-tracing being feasible, but it needs a few optimizations epic could add-in.

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Please do! I didn’t look into other denoising options myself yet, but it’s great to hear about their potential, especially towards real-time pathtracing.

Thank you! I did end up writing a developer feedback post, I tried to keep it concise. Denoising is a very wide and deep subject, because it’s about reconstructing more data out of less, to put it one way. I’m excited Epic’s made both global illumination and denoising available as plugins, so others could experiment with the most effective methods and techniques.

Speaking of techniques, new denoisers have been developed building off of SVGF, such as ReBlur and ReLax. While that probably won’t mean much to anyone not on the technical/rendering side of the work, it does mean we have technologies to achieve stable RT images at a fraction of the sample count-sometimes as low as 1/2 a ray per-pixel.

Granted, this technology overlaps heavily with Lumen, which is itself a ray-tracing system, just with a different sampling and filtering paradigm. I think path-tracing will be used when the performance is good enough to be truly practical, but I’m happy we’re on our way there.