I am trying to using vtkPlane() and vtkCutter in python to read the unstructured data. I have the volume data and wanted to extract data over a plane. So, I pass the plane location and normal to extract the data. The problem is it extracts data fine for few locations. However, for some other locations, it creates spurious data points as attached in the figure. The red dots are required and blue asterisks are for another plane and it has duplicate/spurious as marked.