vtk计算Polydata的面积和体积

主要利用vtkMassProperties。注意：因为只能处理三角面片 的polydata，需要在pipline中前置vtkTriangleFilter，将polydata转换成tiangle mesh的polydata才能接vtkMassProperties。

vtkTriangleFilter triF= new vtkTriangleFilter();     triF.SetInput(ClipData.GetOutput());                 vtkMassProperties polygonProperties = new vtkMassProperties();     polygonProperties.SetInput(triF.GetOutput());     polygonProperties.Update();     double area = polygonProperties.GetSurfaceArea();     double vol = polygonProperties.GetVolume();                 MessageBox.Show("Data area is:" +area.ToString() +"/nData volume is: "+ vol.ToString());     polygonProperties.Dispose();     triF.Dispose();