Like most batch rendering people I have a love-hate relationship with shadow rays. They are wonderfully simple and can easily get you effects like accurate shadows of an eclipse. And yet without getting fancy you start having car interiors turn black because the shadow rays hit the windows. And brute force methods give better pictures given huge amounts of rays. But I think I am finally believing my own BS and thinking computers are fast enough. In my new rendering project I am abandoning shadow rays so the floor under the glass is automatically illuminated. Note the quasi-TV is the only light source in the room. No importance sampling here yet-- just getting the functionality in. (I think there is still a bug in the glass but getting close).