I have been trying to make some 360 VR animations of scenes on earth orbit and for that my starting point has been this excellent How to Create a Realistic Earth in Blender tutorial.
This article describes how I managed to get one of the basic requirements for a realistic earth rendering which is making the clouds cast shadows over the terrain.
I started by setting up a simple scene with two planes illuminated by a distant sphere with an emitting material (the white sphere on the top). The two planes represent the terrain and the cloud cover separated by a very small gap.
I used two high resolution images to texture each of the planes:
Separate renders of both terrain and cloud layers:
Rendering with both layers. The shadows cast by clouds over the terrain are clearly visible.
This was done using the following settings for the Terrain and Clouds materials:
Please note that an additional clouds_inverted.jpg image is used. This is an inverted image of the clouds.jpg image to drive the transparency of the cloud layer: high (white) areas on the cloud cover are transformed into low values driving reduced transparency and projecting shadows over the terrain.
Next step will be modeling how a giant Suzanne will look like from orbit…