Hiya,
I'm working on an Earth model which is seen from space.
I was wondering on advice on how to do the atmosphere so that it thins out when you see the planet from the side.

Right now I did a sphere that use a Fresnel falloff. This looks ok when you are far out but when you fly down it will not work (btw, I see the atmosphere is not fitting perfectly atm, it is wip!)

Some thoughts on how to do it
1. Do a spherical volume where you use VEX to tell how thick it should be so it gradually gets thinner. Downside with this is the voxels may not be smooth enough when you fly closer
2. I found this link http://project-eden.blogspot.com/search/label/atmosphere [project-eden.blogspot.com]
He has custom written in VEX some kind of shader for Rayleight and Mie scattering. This sounds great, but also a bit too hard for me to do.
3. Do a glow in Fusion FX. However would be nice if I did not have to do it in post, always nice to have as much as possible in 3D.

This is one reference
earth [www.universetoday.com]

Any other ideas?

Ok, I created an atmosphere by copying a sphere 100 times an gradually changing the opacity and color with a ramp.
This looks good, but is very slow to render. a 1080p render in Redshift takes 16 minutes to render

Hi Andreas,
I have built a quick setup which makes use of the dot product and a series of ramps to achieve the result you are looking for.

I suggest breaking down the setup and researching the sections you don't understand. Try playing around with other VOP nodes to achieve the results you are looking for.

Best,
Kimber

AndreasOberg
Ok, I created an atmosphere by copying a sphere 100 times an gradually changing the opacity and color with a ramp.
This looks good, but is very slow to render. a 1080p render in Redshift takes 16 minutes to render

Oh geez…don't do that. Just use a volume. I've done it before and it works reasonably well without the need to go crazy, and just by adjusting and tweaking the size and density curve.

Since planets are something that I've done a lot of research in, I found the best option has been to use something like this in AfterEffects:

https://www.videocopilot.net/tutorials/ultra_3d_earth/ [www.videocopilot.net]

I know that's probably not the answer you were looking for, but for me it's all about getting to the end result without worrying too much about which tools I need to use to get there…and in my tests Orb gives me ultimately much better results than other methods.