Necklace

Light transport within the Necklace scene consists of difficult long chains of specular and almost-specular interactions. The radiance-driven path-guiding techniques are able to significantly improve rendering performance over unidirectional path tracing. While in theory, incorporating the product should yield significant further improvements [Herholz et al. 2016], our NPG-Product actually performs worse than NPG-Radiance, presenting an interesting avenue for future investigations. Primary-sample-space path-sampling techniques offer little to no benefit over unidirectional path tracing with our NPS slightly outperforming PSSPG [Guo et al. 2018].