Voronoi is a wonderful visual shape. It would be great to have it in Roassal and this is feasible.

I would first start from having a TRPolygonShape class in Trachel. This class should simply takes a list of points and draw a polygon. To draw the polygon, you need to directly talk to Athens. Your TRPolygonShape should redefine the method computePath and use the right sequence of invocation on the Athens API. Maybe an easy-to-adapt example is the class TRDiamondShape. 

Once you have this class working, you can then think about a RTPolygon class, in Roassal.

Let us know how it goes

Cheers,

Alexandre