Is there an easy way to make volumetric clouds for Cycles?

Question

I'm working on an animation that takes place on a plane. I'd love to include the big detail of clouds moving past through the windows, but I'm using Cycles. I have no experience with the particle emitter, so the only clouds I've ever created were ones from the add-on for Blender Render only.

I want an easy and fluent way to create a huge sky atmosphere, similar to the one in the SFM Saxxy Awards winner, Turbulence.

So, how do I do this easily in Cycles? I'm not with a team or anything, and I don't have hours of spare time to do this. Again, I have no experience with using the particle system.

Answer 1

Let's use the Cloud Generator addon to make nice clouds and the new Point Density Texture to render them inside Cycles!

1. First enable the addon in User Preferences under Object: Cloud Generator.

2. Switch to Blender Render (the addon does not work under Cycles), add some cubes and turn them into clouds with the addon (the UI is located inside Tool Shelf T under Create > CloudGenerator in Object Mode):

   

   

   (we won't use the explosion because it's not a cloud and requires a different Cycles shader)

   After you choose the cloud type it will generate objects like this:

   

   We are interested in the CloudBounds object and in CloudPoints.

3. Switch to Cycles Render and if using pre-2.77 Blender version use CPU rendering (Point Density does work on GPU in 2.77+). We need to give the CloudBounds object a Cycles material:

   

   Play with the Radius and Multiply Node to fine tune the shape and density.

   Delete all the non-used objects from the scene and make sure there are no Blender Internal materials left. All the CloudBounds should have Cycles materials and all the CloudPoints should be without material and hidden from render.

4. Add some lighting: Sun Lamp, Hemi Lights. Render:

   

5. When you get the hang of it create any shapes you like from differently sized and deformed cubes or some basic geometry.

Answer 2

Take a cube and subdivide it with Subdivide Smooth using using some random fractal value and some smoothness.

Make the mesh smooth, add a subsurf modifier and create a material that has no surface but volume scatter with some texture controlling the Density:

On a different layer create an object that is very large and add a particle system that has a low number of emissions, no physics and that uses the cloud object as the render object and has the emitter disabled.

For variety create a few objects with different shapes and textures and use them is other particles systems.