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)); }); }