Like the "Boulder in a Field" scene that I posted a couple of days ago, this started out as a simple exercise to learn about the cloud generator add-on since there doesn't seem to be much in the way of tutorials or examples.
One thing led to another as I began to integrate my clouds with other meshes and images trying to get a realistic effect. The scene itself was inspired by a travel poster that had a winter scene with clouds in a mountain valley capturing the glow of a setting sun.
Eventually my goal became one of creating a similar scene.
I generated dozens of different clouds and experimented with shaping and coloring them as well as adjusting the density.
I can't say that it's very intuitive, but once you understand the controls, I think it has a number of interesting possibilities. I've included some notes I took that explain some of the key controls for generating clouds.
The scene has an image for the sky, one image for the mountain texture, one image for the snow shader lamp (see reference below), and four images of fir trees. Everything else is procedural textures.
There are three meshes: the mountain in the background, the clouds between the mountain and the foreground, and the foreground.
But here are a couple of main lessons I learned in creating this scene.
The cloud generator can be fussy about the settings. Small settings make big changes. One of the first problems I encountered is that when generating a cloud with no background image, the default cloud doesn't look too bad--but it's too round. Put the cloud in front of an image and it develops a greenish glow like a toxic gas cloud. I've included some quick notes that I took while creating the cloud for this scene. It's not a tutorial, but they may be helpful if you have no idea what the cloud controls do. Also, you expose the material and texture controls (described my my notes) for the cloud by selecting the halo particles in object mode. Switching to edit mode allows you to select particles and move them around to create a better looking cloud. Don't move the halo particles outside of the cloud bounding box or they will begin to display as small white specks instead of fluffy cloud material.
That I could sculpt a single cloud into a better shape by selecting groups of halo particles and repositioning them to make the cloud billow more or less.
That combining multiple generated clouds can be tricky as the effects are cumulative. However, I found that I could scale up one cloud's bounding box and move halo particles from other generated cloud sets to make bigger clouds and to shape them. I'm not sure it's worth the effort, but it was an interesting discovery.
Despite the time it took to figure out how to create a decent cloud that reflects the ambient lighting and has some depth to it, I think the cloud in this scene turned out fairly well for a first try.
That images with alpha transparencies do not play well with environmental lighting. The transparent parts of the image cast light shadows onto other objects. I could not find a way to make the alpha channel completely transparent using environmental lighting. If someone has a solution, please post in the comments below. While the overall lighting for the snow and environment was much better using environmental lighting, I has wa forced to abandon that effort and use a five or six different lamps to simulate it.
Lighting in this scene consists of a main sun, a second sun for the blue shadows, a spot lamp to give the cloud between the foreground and background more color, there are two area lamps using negative light to bring back detail that had been blown out by the other lamps.
I'd like to note that Andrew Price (www.blenderguru.com) has an excellent tutorial on creating a mountain scene that uses a snow shader lamp to control how much snow covers the mountain. It is really a very good technique that can be used for other uses as well.
The snow in the foreground could be better, but I didn't want to spend a lot of time on it. And the trees are not as convincing as I'd like. However, they are just there to frame the scene and learning about cloud generation was the real objective of the effort.
As always, the images are free of copyright restrictions. Use anything in the scene as you like. No credit is necessary.