This scene makes use of the path guiding integrator offered by the experimental Mitsuba
Render path guiding fork.
Path guiding builds upon standard path
tracing by integrating information about the location of light sources into the path tracing computation.
Information about light sources is generated by creating a low sample count image of the scene. The goal of these
"training passes" is to more intelligently direct sampling.
The comparison above shows the same scene rendered with a simple path tracer (left) and
path guiding (right). In this example, path guiding finds more difficult light paths around the neck and base of
the bottle, resulting in better resolved highlights.
