Swimming Pool

At the floor of the Swimming Pool is difficult spatially-varying and directionally-narrow specular-diffuse-specular light transport that challenges most unbiased rendering techniques. While primary-sample-space path-sampling techniques offer a small benefit over unidirectional path tracing, radiance-driven path guiding significantly increases rendering efficiency. Incorporating the product (NPG-Radiance) offers only modest additional benefit due to the diffuse nature of most materials used in this scene.