Using After Effects and the free VC Orb plugin, I have the rings cast a shadow on the gas giant.
In this video, I'm revisiting my earlier tutorial showing how to add rings to a planet when using Video Copilot's Orb plugin. I show how to make the rings using Polar Coordinates, then use an Alpha Invert Matte along with a simple expression to cut the rings out. I then add fake shadows using adjustment layers to have the planet cast a shadow on the rings and the rings cast shadows on the planet.
Finally, I show how to recreate the planet and rings in Cinema4D Lite (included in the Adobe After Effects CC licence)
Dan Ebbert's LookAts