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. Incorporating the product (NPG-Product) further improves performance at equal sample counts in this highly-glossy scene. Primary-sample-space path-sampling techniques offer little to no benefit over unidirectional path tracing with our NPS slightly outperforming PSSPS [Guo et al. 2018] with an equal number of samples.