Hi, I am reading CFD data via vtkPLOT3DReader to show contour plot on VTK. Since the result is a compressible flow result, I would like to show the contour of Mach number which is not in the list of scalar functions of vtkPLOT3DReader. Is there any way to define a new solution function from existing solution functions? Thanks. Weicheng Huang at NCSA