C l o u d s

Using a Cloud Component? Watch those keyframes...

Some of the prebuilt Cloud Components have keyframed parameters. That means changes you make will not 'stick' unless you create a keyframe. This is not something you normally think about when creating still images.

Cloud shadows not rendering

Are the clouds close enough to the terrain to see?
Are clouds between the light source and ground?
Try rendering an overhead view and see if shadows appear anywhere on the terrain. If not try moving the sun directly overhead and rendering again.

Multilayered cumulus clouds

Before volumetric clouds were added in WCS6, layers of 2D clouds were the trick to the voluminous cloud look. The secret is to use multiple layers of offset clouds and vary cloud height, texture center, shading and coverage. Adam Hauldren has an excellent Puffy Clouds tutorial describing his technique.