These scenes take advantage of some of the advanced lighting features in Bryce 7.1 Pro and can be very CPU intensive!
On a P4 3.4ghz final renders could take as long as two hours, on an i7 system 12 minutes. Not all the scenes are this processor intensive but fair warning should be given, don't expect instant results.
There are 10 scenes, two for each approach employed demonstrating various strategies for dealing with this subject. These are intended for the kind of people who can learn the most from taking things apart and have a good understanding of Bryce, they are not really intended for beginners.
All the scenes make use of internally generated HDRI and the advanced material filtering that is only available in versions of Bryce 188.8.131.52 or later. The volumetric clouds shown in scene 6 are simply modifications of the free selection provided with Bryce 7.0