[vtkusers] vtkStructuredPointsReader and color

[vtk at le.isac.cnr.it]

Hi..
i have an other problem with vtk 4.0 (tcl/tk on linux).
I have a vtkStructuredPointsReader, and i would like to visualize a 2d images with:


********************************************************
vtkStructuredPointsReader reader
    reader SetFileName "heart.vtk"
    reader Update

vtkPlane cutPlane
    eval cutPlane SetOrigin [[reader GetOutput] GetCenter]
    cutPlane SetNormal 1 0 0


vtkCutter planeCut
   planeCut  SetInput [reader GetOutput]
   planeCut SetCutFunction  cutPlane 


# Isosuperficie 2d 
vtkDataSetMapper mapper 
    mapper SetInput [planeCut GetOutput] 
    eval mapper SetScalarRange [[[[reader GetOutput] GetPointData] GetScalars] GetRange] 

# Linee di livello 
vtkContourFilter contours
   contours SetInput [planeCut GetOutput]
   contours GenerateValues 20 0.0 200

#  mapper SetInput [contours GetOutput]

vtkActor cutActor
   cutActor SetMapper mapper

****************************************************
 
then i want to visualize a volume, with this code:

************************************************
# Create transfer mapping scalar value to opacity
vtkPiecewiseFunction opacityTransferFunction
    opacityTransferFunction AddPoint  20   0.0
    opacityTransferFunction AddPoint  255  0.2

vtkColorTransferFunction colorTransferFunction
  colorTransferFunction AddRGBPoint   64 0 1 0
  colorTransferFunction AddRGBPoint    128 1 0 0
  colorTransferFunction AddRGBPoint    255 0 0 1


# The property describes how the data will look
vtkVolumeProperty volumeProperty
    volumeProperty SetColor colorTransferFunction
    volumeProperty SetScalarOpacity opacityTransferFunction

# The mapper / ray cast function know how to render the data
vtkVolumeRayCastCompositeFunction  compositeFunction

vtkVolumeRayCastMapper volumeMapper
    volumeMapper SetVolumeRayCastFunction compositeFunction
    volumeMapper SetInput [reader GetOutput]
    

# The volume holds the mapper and the property and
# can be used to position/orient the volume
vtkVolume volume
    volume SetMapper volumeMapper
    volume SetProperty volumeProperty
********************************************************

my header file data is:


# vtk DataFile Version 2.0
CT scan data of human heart, courtesy by Henk Mastenbroek RuG
ASCII

DATASET STRUCTURED_POINTS
DIMENSIONS    32   32   12
ORIGIN    0.000   0.000   0.000
SPACING    1.000   1.000   4.000

POINT_DATA   12288
SCALARS colors unsigned_char
LOOKUP_TABLE default

**************************************************

so I visualize the volume with many different color, and the 2d images in the gray scale color.
If I change SCALARS colors unsigned_char in to SCALAR scalars float, i visualize 2d images in many different color and don't view the volume.

What can i do to visualize all images in many different color???

thanks