>>>>> "JZ" == Jianlong Zhou <zhou at isg.cs.uni-magdeburg.de> writes: JZ> hi, all, I use vtkContourFilter to extract the surface from 3D JZ> data set. But the extracted surface is not smooth, it has step JZ> case effect. Which vtk filters can be used to improve surface JZ> quality? vtkPolyDataNormals. prabhu