[vtkusers] Visualizing vtkImageData with negative scalar values

[Sunayana Saha]

Hi,
 
I am trying to use VTK to visualize some image data that ranges from -166114.703125 to 38924.0 
Though the pipeline seems to be working fine when I do not have a huge range and the values are all positive, I can see almost nothing on the output window, when the range is large and contains negative values. Is there any way to come around this problem? My pipeline takes the input in vtkImageData (scalar set to vtkFloatArray) and then applies different vtk compenents in this order:
 
    vtkImageDataGeometryFilter -> vtkWarpScalar -> vtkSmoothPolyDataFilter -> vtkPolyDataNormals -> vtkPolyDataMapper -> vtkActor -> vtkWindowRenderer ...
I tried adding a large positive value to the most negative value to make it zero, and then adding the same value to all the numbers, but that did not help. I think the range is too large. Is there a maximum range (for example, 2048 values between the minimum and maximum values) that VTK objects support?
 
Any suggestions on this problem will be most appreciated.
 
Thanks,
Saha



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