protected override List <Vertex> MakeVertices()
 {
     // CylinderFactory does all the work
     return(CylinderFactory.MakeVertices(true, NSegments));
 }
 protected override Int32Collection MakeTriangles()
 {
     return(CylinderFactory.MakeTriangles(true, NSegments));
 }
 protected override List <Vertex> MakeVertices()
 {
     return(CylinderFactory.MakeVertices(false, NSegments));
 }