Path Tracing vs. Ray Tracing (2016)
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Path Tracing vs. Ray Tracing (2016)
1–10 of 34 posts
Re: Path Tracing vs. Ray Tracing (2016)
#2Wish there were illustrations
Re: Path Tracing vs. Ray Tracing (2016)
#3Wish there were illustrations
Disney's Practical Guide to Path Tracing is a good resource for explaining path tracing: https://youtu.be/frLwRLS_ZR0
Re: Path Tracing vs. Ray Tracing (2016)
#4AFAIK current state-of-the-art in pathtracing are still metropolis light transport methods. Seems like current research is mostly focussed on denoising - which makes sense, since a good denoising provides a valuable shortcut for quicker results.
While I only occasionally glance at new results in this area it seems that CNN-based denoising techniques look quite promising, possibly getting us close to viable real-time pathtracing at least for "suitable" scenes. I am more confident than ever that a shift to traced renderers could be next - this has nothing to do with RTX and the buzz around it though...
Re: Path Tracing vs. Ray Tracing (2016)
#5I wonder what convolutional neural networks bring to the table. Maybe you could use them to get rid of the noise, or then you could use ray tracing for the base image and train a CNN to "recolour" that image based on a noisy path traced one of the same scene.
This demo is 4 years old, but the noise still seems to be a problem: https://youtu.be/BpT6MkCeP7Y
If anybody's got more recent impressive demos to link, I'd like to see how things have been developing.
Re: Path Tracing vs. Ray Tracing (2016)
#6I wonder what convolutional neural networks bring to the table. Maybe you could use them to get rid of the noise, or then you could use ray tracing for the base image and train a CNN to "recolour" that image based on a noisy path traced one of the same scene. This demo is 4 years old, but the noise still seems to be a problem: https://youtu.be/BpT6MkCeP7Y If anybody's got more recent impressive demos to link, I'd lik…
This one is 3 years old, showcasing Brigade https://vimeo.com/124065358.
It looks like this is part of Octane Render.
Re: Path Tracing vs. Ray Tracing (2016)
#7AFAIK current state-of-the-art in pathtracing are still metropolis light transport methods. Seems like current research is mostly focussed on denoising - which makes sense, since a good denoising provides a valuable shortcut for quicker results. While I only occasionally glance at new results in this area it seems that CNN-based denoising techniques look quite promising, possibly getting us close to viable real-time…
> I am more confident than ever that a shift to traced renderers could be next - this has nothing to do with RTX and the buzz around it though
You mean you being confident or the shift has nothing to do with RTX?
The purpose of RTX is to solve the chicken-and-egg problem of hardware first or software first. It's much less likely for a company to invest the effort into developing a path traced renderer without hardware support, but without software support there's no demand for the hardware. RTX is supposed to kickstart real time path/ray traced graphics.
Re: Path Tracing vs. Ray Tracing (2016)
#8A bit outdated, and not entirely accurate, at least for film VFX...
This bit:
> but until path tracing times are measured in minutes per frame, as opposed to the hours or days they are now, ray tracing (or rasterization, especially micropolygon rasterizers like the one powering RenderMan) remains the better option for many classes of rendering tasks.
wasn't even true in 2016 - RenderMan (PRMan) 19 added a pathtracer and eventually in 21 removed entirely its REYES rasteriser, and pretty much the entire VFX film/animation industry is using pathtracing now.
Artist time is much more expensive than machine time, and not having to tweak things like materials / lights in the PBR realm that path tracing lives in per shot / sequence to fake things like GI (like the article mentions is a good alternative - it's not) is where a lot of the speedup has come from with iteration times.
If anyone's interested in state-of-the-art for film VFX, five papers on the five most used pathtracing renderers used in VFX were recently released:
https://jo.dreggn.org/home/2018_manuka.pdf
https://www.yiningkarlli.com/projects/hyperiondesign.html
https://www.arnoldrenderer.com/research/Arnold_TOG2018.pdf
https://graphics.pixar.com/library/RendermanTog2018/paper.pd...
https://fpsunflower.github.io/ckulla/data/2018_tog_spi_arnol...
Re: Path Tracing vs. Ray Tracing (2016)
#9AFAIK current state-of-the-art in pathtracing are still metropolis light transport methods. Seems like current research is mostly focussed on denoising - which makes sense, since a good denoising provides a valuable shortcut for quicker results. While I only occasionally glance at new results in this area it seems that CNN-based denoising techniques look quite promising, possibly getting us close to viable real-time…
Metropolis has lots of advantages, but it has serious problems for realtime or animated applications, in that it tends to flicker or have noticeable low-frequency noise. This is less of a problem for stills.
RTX can absolutely accelerate path tracers, even for non-realtime applications. The underlying framework is definitely flexible enough to support a variety of rendering algorithms, it's basically accelerated BVH and intersection, with shaders to control behavior.
The biggest advancement I've seen lately is advances in denoising - the ML-based denoisers are incredible, but others are also impressive.
Re: Path Tracing vs. Ray Tracing (2016)
#10Maybe I'm wrong, but the terminology isnt that clear. Path tracing is a sub field of Ray tracing - Ray tracing refers to the camera into scene Ray generation. What he describes as raytracing sounds like the whitted recursive algorithm.