Setup:

How to import this node group in your project:

1. In your project, go to "File".

2. Click on "Append". 

3. Select this file (Beautiful_Clouds.blend).

4. Go to "NodeTree" and select "Beautiful_Clouds". 

Its that simple! The node group is now in your project and you can now access it in the material editor when pressing Shift+A, in the "Group" category.

Scene Setup:

(Remember that you can always change the size of your clouds container or the clip start/end)

1. Create a cube with a length and width of about 50km and a height of about 5km (you can always change its dimensions later).

2. Apply its scale.

3. Change the View "Clip Start" to 0.1 and "End" to 200 000

4. Create a material that contains the node group.

5. I recommend putting the dicing scale of the volume in the render settings between 0.1 and 0.2 for better results.

That's it, your clouds are now in your scene!

*Do not forget:

Remember to always apply the scale of your object after changing its dimensions.

Inputs/Outputs:

Inputs:

• Clouds Color: The color of the clouds
• Seed: The value indicates the random shape of the clouds.
• Coverage: The amount of clouds in the sky.
• Clouds Noise Intensity: The amount of displacement of the clouds.
• Clouds Absorption: The density of the clouds.
• Clouds Density: The value that sets how white the clouds are.
• Clouds Scale: The scale of the clouds
• Clouds Scale Random: The difference in scale between each cloud (0 = No scale variation, 1 = Maximum scale variation).
• Clouds Height: The scale of the clouds on the Z axis.
• Clouds Clipping mask: Hide the clouds that are "cut" on the border of the domain. The clipping mask output can help you visualize the masking on each axis.
• Hide X/Y Clipping ?: A 0 or 1 value in which 0 means "No" and 0 "Yes".
• Clouds Location: The location of the clouds.
• Clouds Rotation: The Rotation of the clouds.

Warning: Do NOT apply the location of the object which contains the clouds. Doing so might cause the clouds to disappear. 

Outputs:

Clouds: The clouds that you generated

Clipping mask: A visualization in white of the clouds that are gonna be cut if "Hide X/Y Clipping ?" is set to 1. Use the "Separate XYZ" node to view each axis

Precisions:

If the clouds density or absorption does not appear to change the appearance of your clouds, lower your dicing scale until the clouds look normal.

I also recommend putting the volume bounces in the render settings to at least 1 to make the light bounce inside the clouds which helps make them more photorealistic.

*Please take note that like with any other volume shaders, the clouds may take a long time to render even on powerful setups.

Changelog:

Version 1.1:

• Updated the demo scene
• Tweaked some values