[vtkusers] how to draw polygons using vtkPolyData

[路明月]

Hi All,
I have a question about vtkPolyData.I want to draw a polygon like shp.jpg. But when I use the vtkPolyData to draw, it gave me the result like shp2.jpg.Maybe I make a misunderstanding somewhere.Please help me to draw polygons by vtkPolyData.
Thank you for your help. 
Your sincerely,
Joy Wang
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