Bedroom
The Bedroom is a typical interior scene with a mix of textured glossy and diffuse materials that is easy to render for a unidirectional path tracer due to large light sources: the windows are modeled as diffuse area emitters. Since most light transport is governed by diffuse materials, radiance-based guiding techniques generally improve over unidirectional path tracing. However, highly glossy materials such as the ceiling lights made out of rough glass look significantly worse when rendered using radiance-based path guiding. At equal sample counts, this issue is addressed and noise improved overall by using our product-based guiding (NPG-Product) with learned multiple-importance-sampling weights. 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.