In the Halfland sky there are a couple of monofiliant lines to run dimensional clouds in front of the painted versions. They can be moved along like clothes on an old fashioned clothesline via pulley. The clouds can be lit from the front or sides or behind with white or colored lights for changing time of day or type of weather. NICE!
On the right, a cloud is photographed behind the plastic sky scrim. I like the realistic shading this technique gives the cloud shapes and how dreamy the sheeting makes things seem.