Hacker News Reader

Comment by nielsbot | Hacker News Reader

So they're not ray tracing everything, right? If I understand correctly, they're "filling in some of the blanks" using an ML algorithm? Does that really work for general purpose rending?

View on HN

It is never mentioned explicitly, but my hunch would be that primary visibility is still done using rasterisation and that ray tracing is only used for reflections, shadows and ambient occlusion.

This is how most film rendering was done ten years ago too.

They are properly raytracing soft shadows, no need for AO.

AO and soft shadows are orthogonal and are often used simultaneously. A few direct light sources (point lights, spots, infinite) with soft shadows and additionally an environment light (dome or half dome) with AO.

Yes they are raytracing some pixels and filling the blanks with ML/DL. I believe you could actually ray-trace everything depending on your target output. In these demos they're targeting many dynamic lights, reflections and refractions. If you were content with less reflection bounces, less lights and lower resolution you could easily ray-trace the whole frame with 166 mil rays per frame available.

What is your source for the ML claim? I know very decent and fast screen space filters that do kot use any learning and can work with 1spp (pure noise for the hunan eye).

ML based denoising for various ray tracing applications is a hot topic at SIGGRAPH this year. Here's one NVIDIA paper on the topic from last year: http://research.nvidia.com/sites/default/files/publications/...

There are also some impressive new non ML based denoising results too however and it's unclear to me at the moment where NVIDIA is using ML based denoising and where they are using more traditional filters in the demos they've been showing. I think at least some of the real time ray traced ambient occulsion and soft shadow demos have been using more traditional non ML based filtering approaches.

They are ray tracing everything. They use an ML-based filter to reduce sampling noise.

Reply on news.ycombinator.com