Blender parallax occlusion clouds shader

Fast noise free, thick procedural parallax clouds shader that's dynamic, in perspective and does not involve any volumetrics. You can't render that fast in Cycles with volumetrics when you don't have extreme rig, I have not seen yet anyone done it this way.

You can control:

• coverage
• thickness via layers distance
• evolution via z position
• scale, position and rotation
• colour of clouds with Nishita settings, respecting air dust ozone density and and sun position
• full day night cycle
• moon size position brightness and colour
• brightness of clouds
• clouds sharpness
• independent sky strength and clouds strength, separate for the camera, environment influence and gloss reflections.
  

Extra:

Clouds self shadow moderately follow sun direction, might improve it in future.

Stars and moon for night scene, show up based on Nishita sun elevation.

Custom mask for when you would like more clouds at the horizon or one direction, or plug something yourself.

Organized nodes into couple groups and named crucial nodes.

This clouds shader renders even with one sample in contra to volumetric alternatives.

Cloud covering Nishita sun would render the whole scene in one global shadow, fixed this and instead shader ignores clouds occluding sunlight. For better drop shadow file include plane object with the same base noise, and drive it with the settings from the world shader so you have clouds drop shadows in your scene.

You can edit base noise and to make it your own or stylized, because its not a plugin but node tree shader and everything is editable.

Disclaimers:

Shader was created for Cycles and uses Nishita, might work in future when Blender gets Nishita in Eevee.

If you duplicate the world shader, you will have to update the purple drivers passing the variables in the new copy, else they will refer to original version.

Adding more distance between layers or sharpness will increase the visibility of separation between them.

Empty scene with this shader renders perfect noise free HD image in 2.5 sec on 2060s with 1 sample.

Tip:

If you notice individual layers, try to change clouds evolution or reduce sharpness and distance between layers.

To make clouds look more overcast, I recommend increasing clouds gamma and reducing camera strength setting, custom colours also can give great results.

To fit the drop shadow object to your scene size, remember to apply object scale, and if drop shadow animation is moving to fast, bring the object closer to your ground level but above highest object in your scene.

You can replace the moon image for something else, just make sure it has the alpha channel.

If you want to import this into your project with drop shadows, select the drop shadow object it should pull the world shader along with it. Else import the shader or add the whole file into your asset library.

Use it in your commercial work, yet do not redistribute.