When doing bigger/wider lighting setups, the distances grow and ordinary soft boxes and such doesnt work since they become relatively small and creates harsh shadows. Then its great to use really BIG diffusors.
In this image we wrapped the whole exterior of the building in milky white plastic to get the huge windows like this. To get the correct depth of light from outside the window, the flash needs to be far away, thus demands alot of power. I think we used a twin head and two 2400Ws generators for the outside flash. Inside I had a strip light (without fabric) from the left shooting through a big diffusion screen. To the right there was a silver reflector that bounced back the light from a gridded flash. The reason why I bounced it was because I needed the extra depth of light one get when using long distances.