[vtkusers] stupid question re: volSimple.py

[Maneesh Yadav]

Thanks for the help Robert, I am running vtk3.2, but now I realize I
think am  just plain running out of memory (I'm running this on a machine
with 128M ram)...but I think I do see an image briefly :)

On Wed, 8 Aug 2001, Robert Belleman wrote:

> Maneesh,
>
> On Tue, Aug 07, 2001 at 03:54:32PM -0400, Maneesh Yadav wrote:
> > Hi all, I'm having a bit o' trouble visualizing my data...
> > I stripped the header of the stack as was suggested earlier on the list
> > and I should be left with the raw data (it's the right size)...
> > to load the data I do this:
>
> I have converted your script to Tcl to verify your code.
>
> > reader=vtkImageReader()
> > reader.SetFileName("dataset.raw")
> > reader.SetDataExtent(0,255,0,255,0,249)
> > reader.SetFileDimensionality(3)
> > reader.SetHeaderSize(0)
> > reader.SetDataByteOrderToLittleEndian()
> > reader.SetDataOrigin(0,0,0)
> > reader.SetDataScalarTypeToUnsignedChar()
> > reader.SetDataSpacing(1.0,1.0,1.0)
> > reader.GetOutput().ReleaseDataFlagOn()
>
> This is fine. Note that "reader.SetDataByteOrderToLittleEndian" isn't
> really needed since the data is 1 byte per pixel (byte order is important
> of the data consists of more than one byte per voxel). The values you set
> for HeaderSize, DataOrigin and DataSpacing are the same by default, I
> think, but it can't harm to set them explicitly.
>
> > opacityTransferFunction = vtkPiecewiseFunction()
> > opacityTransferFunction.AddPoint(20,0.0)
> > opacityTransferFunction.AddPoint(255,0.2)
>
> You may want to change this a little. This will result in opaque voxels
> for values between 0 and 20 which will obscure the "interesting" bits.
>
> Try
>
> opacityTransferFunction.AddPoint(0, 0.8)
> opacityTransferFunction.AddPoint(255, 0.0)
>
> > colorTransferFunction = vtkColorTransferFunction()
> > colorTransferFunction.AddRedPoint(0.0,0.0)
> > colorTransferFunction.AddRedPoint(64.0,1.0)
> > colorTransferFunction.AddRedPoint(128.0,0.0)
> > colorTransferFunction.AddRedPoint(255.0,0.0)
> [... etc.]
>
> You are probably using an old version of Vtk; my version warns me that
> Add(Red|Green|Blue)Point is deprecated and I should use AddRGBPoint
> instead.
>
> Try
>
> colorTransferFunction.AddRGBPoint(0,   0.0, 0.0, 0.0)
> colorTransferFunction.AddRGBPoint(64,  1.0, 0.0, 0.0)
> colorTransferFunction.AddRGBPoint(128, 0.0, 1.0, 0.0)
> colorTransferFunction.AddRGBPoint(192, 0.0, 0.0, 1.0)
> colorTransferFunction.AddRGBPoint(255, 0.0, 0.0, 0.2)
>
> > The program starts a window comes then dissappears (no coredump)...
>
> Ah... Maybe you should try a newer version of Vtk, because everything
> else looks fine to me.
>
> Good luck,
> -- Rob
>
> --
> [] Robert Belleman         X  Section Computational Science            []
> [] robbel at science.uva.nl  |X| University of Amsterdam, the Netherlands []
> [] tel: (+31) 20 525 7510  X  http://www.science.uva.nl/~robbel/       []
>
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