ReSTIR GI: Path Resampling for Real-Time Path Tracing

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kintuX
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ReSTIR GI: Path Resampling for Real-Time Path Tracing

Post by kintuX » Mon Sep 20, 2021 3:57 pm

Image
Source: https://research.nvidia.com/publication/2021-06_ReSTIR-GI%3A-Path
Paper: ReSTIR GI: Path Resampling for Real-Time Path Tracing
Even with the advent of hardware-accelerated ray tracing in modern GPUs, only a small number of rays can be traced at each pixel in real-time applications. This presents a significant challenge for path tracing, even when augmented with state-of-the art denoising algorithms. While the recently-developed ReSTIR algorithm [Bitterli et al. 2020] enables high-quality renderings of scenes with millions of light sources using just a few shadow rays at each pixel, there remains a need for effective algorithms to sample indirect illumination.

We introduce an effective path sampling algorithm for indirect lighting that is suitable to highly parallel GPU architectures. Building on the screen-space spatio-temporal resampling principles of ReSTIR, our approach resamples multi-bounce indirect lighting paths obtained by path tracing. Doing so allows sharing information about important paths that contribute to lighting both across time and pixels in the image. The resulting algorithm achieves a substantial error reduction compared to path tracing: at a single sample per pixel every frame, our algorithm achieves MSE improvements ranging from 9.3x to 166x in our test scenes. In conjunction with a denoiser, it leads to high-quality path traced global illumination at real-time frame rates on modern GPUs

Authors:
Yaobin Ouyang (NVIDIA)
Shiqiu Liu (NVIDIA)
Markus Kettunen (NVIDIA)
Matt Pharr
Jacopo Pantaleoni (NVIDIA)

Publication Date: Thursday, June 24, 2021
Published in: Computer Graphics Forum (Proceedings of High Performance Graphics)

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a1-kh
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Re: ReSTIR GI: Path Resampling for Real-Time Path Tracing

Post by a1-kh » Mon Sep 20, 2021 5:53 pm

Sorry for being late, here is a video explains it in detail :
https://youtu.be/kI5uEMXvreY?t=7294

some interesting parts of the video :
https://youtu.be/kI5uEMXvreY?t=7817
https://youtu.be/kI5uEMXvreY?t=8134

some limitations :
- Detailed scenes may make it unstable
- Highly glossy visible objects
- Can not do caustics :(

Conclusion :
- Extending the (ReSTIR) algorithm ti GI : 10x ~ 166x noise improvment
- Using Spatiotemporal reservoir resampling technique
- A new idea : treat a path as a light source (or a sample)

kintuX
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Re: ReSTIR GI: Path Resampling for Real-Time Path Tracing

Post by kintuX » Mon Sep 20, 2021 8:23 pm

Nice & Thank you for extra info :)

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Sharlybg
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Re: ReSTIR GI: Path Resampling for Real-Time Path Tracing

Post by Sharlybg » Tue Sep 21, 2021 10:36 am

This Look much better and less limited :
https://research.nvidia.com/publication ... l-Radiance
Support LuxCoreRender project with salts and bounties

Portfolio : https://www.behance.net/DRAVIA

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