Large scale cloudscapes in cycles

Hi,

This may be a bit of a vague thread, for which I apologise in advance, but I could do with some advice on generating large scale procedural skies and cloudscapes in cycles.




To give you some background, i’ve spen the past twelve months sorting the CGi for a short film (steampunk airships) using blender. Due to limitations on time and the processing power available, we’ve kept it fairly simple so far - procedural sky background (or image in some cases), with the clouds rendered as images and inserted on planes. This has been quite effective, but it lacks a depth and feel you see in more advanced renders. For the next short film, i’d like to get the backgrounds to a look/quality not dissimilar to this: (eye of the storm by Lovett):

But i’m struggling to do so. I’ve tried using kilbeeu’s cloud material, to no effect - all I get is jagged edges or strange anomalies, and i’m a little stumped. Does anyone have any ideas on a good way to do this, both from a materials/backgrounds point of view, and to a lesser extent, compositing?

-Matt

With a lot of careful pre-planning, I think you could get good effects using high-resolution cloud imagery (either photographic or specially-generated CGI plates) and a combination of multiplane-style “billboards” (though not flat – shaped as needed, with depth along the edges) and practical effects like particle clouds (for the closer clouds that pass by quickly).

“Multiplane,” if you aren’t familiar with the term, means using flat or close-to-flat images, in this case mapped to meshes and animated to represent the parallax exhibited by seeing the clouds at various depths in the picture field. I used this for the wide shot cloudscape @ 0:43s in my Project Dewdrop video. In that case I used flat planes and very subtle motion, but the parallax displayed helps sell the shot. For more dramatic results, as in the video, greater differential motion would be needed, plus perhaps using shaped meshes with Shape Key animation to give the effect of the clouds forming and reforming as they move; it need not be major action as long as individual shots are not held too long.

Particle effects can do dust very well (though I haven’t tried it in Cycles yet), as can be seen in Monster Movie. The clouds scudding across the foreground & midground could be done this way.

Planning & tests are the keys to this kind of fakery, so be prepared to do both extensively.