Ok, I've gotten nowhere trying to distort a single cloud layer at certain altitudes with transforms, twist and shears or redirects.(someone managed to use twist and shear on clouds here before, in a thread called 'clouds follow terrain', I think, but I can't get the effect to appear only at a certain desired altitude when it's used on a cloud layer, only all over).
I have managed to create a simple demo scene that uses 2 cloud layers driven by 2 similar painted shaders(as Ogre stated earlier), in the 'plan Y' setting, painted on the ground. I'll attach it here.
It's crude but, it's a working model...
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