Blender 2.76 and Mitsuba Renderer 0.6

Bottles Rendered with Path Tracing and Path Guiding
      This scene makes use of a number of integrators offered by the experimental Mitsuba Render 0.6 path guiding fork, including path tracing, bidirectional path tracing, and path guiding. Path guiding builds upon standard path tracing by integrating information about the location of light sources into the path tracing computation. First, information about light sources is generated by creating a low sample count image of the scene. Second, luminance information is derived from the image and sorted into an acceleration structure to be used in subsequent renders. The goal of these "training passes" is to more intelligently direct future samples and computational resources.

      The comparison at right shows the same scene rendered with a simple path tracer (on the left) and path guiding (on the right). In this example, path guiding finds more difficult light paths around the neck and base of the bottle, resulting in brighter highlights overall.