Bezier Curves Sketchup Plugin Development
The following SketchUp drawings shows one how to develop an item that has curved sides, in this case a drafting curve. (But it may be used for any curved shape). (First off SketchUp free does not come with a 'Bezier' curve tool it can be had at this Ruby Script page:see bottom of this page). To begin we will first use a real french drafting curve to develop the outside shape of the curve within SketchUp, see the following SketchUp drawings for an explanation. And now may put our efforts to use.
Bezier Curve Online
Bezier Spline Sketchup
If you don't have a Bezier drawing tool within SketchUp you may obtain it here.