Tutorials

First it should be mentioned that this method is useful only for those cases when the planet is shown at the middle or background.

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1. Create the scene in 3D MAX

2. In Geometry --> geosphere create a sphere sized 132 (it is not important what size it will be, it's up to you to decide)
3. Duplicate it twice increasing the size by 1% with each duplicating
4. The final sequense of spheres will be named accordingly: surface-the surface of the planet; cloud-the layer of clouds(if you want a more realistic view, create several layers); atmosphere-the atmosphere.

If you’ve done everything right the result will be as follows:

5. Let’s start from above:

Atmosphere.
Create Blinn material
Main parameters are set as follows:
Specular level -- 20
Glossiness -- 5
Soften -- 0,1

The atmosphere in the picture should only be shown by bluish thin rim, therefore gradient maps will play the main role:
In Diffuse Color bookmark create Gradient Ramp material setting it like in the picture below. Your atmosphere depends on the color you choose.
In Opacity bookmark also create Gradient Ramp material, here only monochrome shades of gray are used. It is desirable that the white color stripe coincides. This will be the reflection in the atmosphere.

And there is only one map left which defines the reflecting regions of Fallout:

Now it’s time to make clouds:

6. Cloud

Create Blinn material
Main parameters are set as follows:
Specular level -- 160
Glossiness -- 15
Soften -- 0,1

Insert the picture of cloudiness into the Diffuse Color bookmark (in web there are many finished samples and I won’t pay special attention to this).

It’s possible to put the same map as in Diffuse Color into the Opacity bookmark, only treat it previously having changed the colors to the shades of gray.

Create other bookmarks as shown in the picture below:

more here