Never mind.I have checked them before, they mainly find the closest point, maybe it is not fit for my case. -- View this message in context: http://vtk.1045678.n5.nabble.com/How-to-know-a-coordinate-inside-or-outside-a-vtkPolyData-tp5729019p5729023.html Sent from the VTK - Users mailing list archive at Nabble.com.