Thanks, folks.
Kadri, I used both. The planet surfaces are a mix of fractal and images. It can be shaded any way, if you remove the maps, the fractal will take over, just need to adjust the colours to suit.
The rings are also using maps. I will make them solely using functions soon, like I did in my older faux-Saturn projects.
It has been a really testing project, actually. Shadow casting was a bit of a pain(!) and also lighting with a Sunlight node when the default planet is disabled proved a lot of hassle! It seems that when the Sun is at or, below, '0' elevation that it still 'thinks' that there's an occluding planet surface there and no light gets through, even when the objects are below '0'.
I think a Lightsource node will work better. I haven't tested that, though... What I'd really like to do is to just use a little Luminosity so the rings can be viewed from any angle, regardless of lighting direction, a 'shadow exlcusion' Luminosity function would be ideal. Is that possible? I haven't managed to figure that out yet. I think some 'Get Ray Origin' tricks might be the way to go.
I'm done with it, at least for a while anyway, I've hurt what little brain I have over this last few days trying to make a universal model that works in most lighting situations.
Cheers!
