Demonstrate SoCircularExtrusion usage.
When the demo starts a SoCircularExtrusion is loaded. The user can interactively change the SoCircularExtrusion radius and its starting and ending points, by mean of sliders. Since the SoCircularExtrusion representation is simplified basing on the SoComplexity state value, the user can see how the SoCircularExtrusion changes by sliding the Complexity control.