[vtkusers] SetScalars of SG from Field

[Randy Heiland]

I'm trying to update scalars in a struct grid from a FIELD file, but the
results don't get re-rendered properly.  What am I missing?

Here's some Python code & files to demonstrate (using VTK 4.0):

from vtk import *

ren1 = vtkRenderer()
renWin = vtkRenderWindow()
renWin.AddRenderer(ren1)

iren= vtkRenderWindowInteractor()
iren.SetRenderWindow(renWin)

#--------------------------------------------------
sgr = vtkStructuredGridReader()
sgr.SetFileName("sg.vtk")
sgr.Update()
sg = sgr.GetOutput()

srange= sg.GetPointData().GetScalars().GetRange()
print 'srange = ',srange

#----------------------

mapper = vtkDataSetMapper()
mapper.SetInput(sg)
#mapper.SetScalarRange(0.,1.)
#mapper.SetLookupTable(lutBlueRed)

actor = vtkActor()
actor.SetMapper(mapper)

ren1.AddActor(actor)

#ren1.GetActiveCamera().Elevation(-90)
#ren1.GetActiveCamera().Roll(-90)

renWin.Render()

w2if = vtkWindowToImageFilter()
w2if.SetInput( renWin )
pnmWriter = vtkPNMWriter()
pnmWriter.SetInput(w2if.GetOutput())
pnmWriter.SetFileName("sg1.pnm")
pnmWriter.Write()


#--------------------------------
# Now try to update scalars from a Field file
dor = vtkDataObjectReader()
dor.DebugOn()
dor.SetFileName('field.vtk')
dor.Update()

so = vtkFloatArray()
so = dor.GetOutput().GetFieldData().GetArray(0)

sg.GetPointData().SetScalars(so)
# does this help?
sg.GetPointData().Modified()
sg.Update()

srange= sg.GetPointData().GetScalars().GetRange()
print 'srange = ',srange

actor.Modified()
renWin.Render()
pnmWriter.SetFileName("sg2.pnm")
pnmWriter.Write()

iren.Start()

------------ sg.vtk:
# vtk DataFile Version 1.0
title line
ASCII
DATASET STRUCTURED_GRID
DIMENSIONS 3 2 1
POINTS 6 float
  0.0 0.0 0.0  1.0 0.0 0.0  2.0 0.0 0.0
  0.0 1.0 0.0  1.0 1.0 0.0  2.0 1.0 0.0
POINT_DATA 6
SCALARS foo float
LOOKUP_TABLE default
  0.0
  1.0
  2.0
  0.0
  1.0
  2.0

----------- field.vtk
# vtk DataFile Version 1.0
dummy field data
ASCII

FIELD all 1

temp 1 6 float
0 0 0 1 1 1