You are almost done. You need to convert `CLRVariant(VT_ARRAY(1D)|VT_R8)` back into .net object via `toObject` or syntax sugar `[]`. plt.AddScatter(xs[], ys[]) Run
And here is the code that don't need the C# compiler. import winim/clr var ScottPlot = load("ScottPlot.dll") Plot = ScottPlot.GetType("ScottPlot.Plot") dataX = toCLRVariant([1'f64, 2, 3, 4, 5], VT_R8) dataY = toCLRVariant([1'f64, 4, 9, 16, 25], VT_R8) var plt = @Plot.new(400, 300) plt.AddScatter(dataX[], dataY[]) plt.SaveFig("console.png") Run Moreover, I don't know about iText7, your code seems ok. However, my guess is lacking the dependencies.