You must first install the latest LibFredo6 (v14.3b or higher) for the plugin to function.
Once installed, you can find the tools under Tools > Fredo6 Collection > Curvizard or by enabling the Curvizard toolbar. Why Use Curvizard? curvizard sketchup plugin download
Curvizard is a suite of interactive tools designed to modify existing edge sequences (contours) and SketchUp curves without drawing new ones: You must first install the latest LibFredo6 (v14
The plugin provides a suite of interactive tools to refine contours and curves: Make Curve curvizard sketchup plugin download