Borgleader wrote:It may not be so obvious on the picture but basically the material/shader should be transparent where the normals are facing the camera and should gradually become opaque at the edges.
Ok I got it. Ctzn, the idea here is not to fake it by making it an emitter, but more a semi transparent diffuser with falloff.
This is a diffuse material at grazing angles and a null material at normal incidence. It's absolutely not fake.
However, not possible to do it with Indigo without faking something, as this is clearly a custom brdf material. It would require additional coding of indigo.
The possible fake I can imagine will have one drawback : energy loss.
Do you want to model it as a separate sphere which is slightly larger than the planet sphere, or directly integrated in the planet surface material? In the second case it would not suffer of the energy loss problem but then you cannot use bump or phong on your surface or it will look weird.
In the first case, define a blend of null and diffuse with for instance 80% for the null. Then make an albedo shader equal to one of the above equations