This video provides a quick introduction to basic tools included in the Driving Dimensions 0.1 for SketchUp 6: introducing Driving Dimensions toolbar, setting and editing length and radius dimensions, using hide/show functionality.
When you change the radius of an end-circle (end-arc) of a cylindrical surface, the opposite radius is changed correspondingly. If you change both radius manually, the cylindrical surface becomes conic. This behavior is supported starting with version 0.2.