>>>>> "VN" == Vidhya Narayanan <gtg066j at mail.gatech.edu> writes: VN> I want to select a point on an iso surface generated by VN> the MC algorithm and dispay the normal of that point.Can VN> anyone suggest a simple way to do this. Use one of vtkPicker's subclasses (vtkPointPicker, vtkCellPicker etc.). cheers, prabhu