Additional Sky Traffic

I worked out how to use a background shader last night to exclude rendering parts of a scene. That meant even though the rocket and tower were already rendered in the foreground I could still render out objects behind them (midground objects). With the background shader on the foreground objects Maya would render only the midground object parts it could see. The parts where the foreground objects obscured the midground would become an alpha channel, meaning I could composite my midground over the top of my foreground and it would still be behind. Phew that was a mouthful.

Hence the flying car addition without rendering my whole scene again :)