NVIDIA’s all-new ReSTIR algorithm uses real-time ray tracing and dynamic direct lighting to renders millions of light sources interactively, at high quality, and without needing to maintain complex data structures. The team resampled a set of candidate light samples and then applied further spatial as well as temporal resampling to leverage information from relevant nearby samples.
This new approach allows for unbiased spatial and temporal reuse of nearby samples, thus leading to an even more efficient biased variant. Their algorithm manages to deliver one to two orders of magnitude reduction in error compared to previous approaches while also requiring only simple image-space data structures. What does this mean? It’s suitable for high-end graphics cards, and could lead to real-time rendering of scenes with thousands and millions of dynamic light sources simultaneously. Or, you could just ask 3D artists to create renders from a simple animated scene and select your favorites.
One way to view our technique is that we have shown that filtering and denoising need not remain a post-process that is performed once rendering completes—effectively, we have moved denoising into the core of the renderer and filter PDFs rather than colors,” said the researchers.