public void BoxConversionShouldWork()
        {
            CreatePartDoc(modelDoc =>
            {
                var planeSurf  = (Surface)Modeler.CreatePlanarSurface2(new[] { 0, 0, 0.0 }, new[] { 0, 0, 1.0 }, new[] { 1, 0, 0.0 });
                var parameters = planeSurf.GetBSplineSurfaceParams(1e-5);

                var foo = parameters.ToSurface();

                //#####################################
                var d0 = foo.ToSheetBody().DisplayUndoable(modelDoc, Color.Blue);
                return(new CompositeDisposable(d0));
            });
        }