[vtkusers] all my streamlines are in white :(

[Marcelino Rodriguez Cancio]

Yifei,

>> no lookup table is set for the streamMapper. Why?
Because vtkPolyDataMapper has a default vtkLookUpTable.

If I'm correct vtkPolyDataMapper colors via the active scalars of the dataset. A common trick is to color the vectors by their magnitude (although this may not be want you want). You may achieve this using vtkAssingAtributte with something like the following:

aa = vtkAssignAttribute()
aa. SetInput(grid)
#Not so sure how to do this in Python since I have only worked in C++ and TCL
aa.Assign("SCALARS", "VECTORS", "POINT_DATA")

streamer.SetInputConnection(aa.GetOutputPort())


Hope it helps
Marcelino


De: vtkusers-bounces at vtk.org [mailto:vtkusers-bounces at vtk.org] En nombre de Yifei Li
Enviado el: miércoles, 09 de noviembre de 2011 10:07 a.m.
Para: vtkusers at vtk.org
Asunto: Re: [vtkusers] all my streamlines are in white :(

Marcelino,

Thank you. I'll try you suggestion.

But at the same time, if you take a look at the example that comes with VTK Examples/GUI/Python/StreamlinesWithLineWidget.py, no lookup table is set for the streamMapper. Why?
Yifei
On Wed, Nov 9, 2011 at 8:16 AM, Marcelino Rodriguez Cancio <marcelinorc at uclv.edu.cu<mailto:marcelinorc at uclv.edu.cu>> wrote:
Yifei:

I think you need to add a vtkLookUpTable:

lut = vtkLookupTable()
lut.SetHueRange(667, 0.0)
lut.Build()

streamMapper.SetLookupTable(lut)

Greetings
Marcelino


De: vtkusers-bounces at vtk.org<mailto:vtkusers-bounces at vtk.org> [mailto:vtkusers-bounces at vtk.org<mailto:vtkusers-bounces at vtk.org>] En nombre de Yifei Li
Enviado el: martes, 08 de noviembre de 2011 08:24 p.m.
Para: vtkusers at vtk.org<mailto:vtkusers at vtk.org>
Asunto: [vtkusers] all my streamlines are in white :(

Hi all,

I want streamlines to be colored according to scalar values, but they are all white. Can someone help me figure out what's wrong with my code? Thanks  -Yifei

# vector field data
grid = vtkStructuredGrid()
grid.SetPoints(points)
grid.GetPointData().SetVectors(vectors)

....
streamer = vtkStreamTracer()
...
# show streamlines using ribbon
rf = vtkRibbonFilter()
rf.SetInputConnection(streamer.GetOutputPort())

streamMapper = vtkPolyDataMapper()
streamMapper.SetInputConnection(rf.GetOutputPort())

# I thought the following lines should make it
streamMapper.ScalarVisibilityOn()
streamMapper.SetScalarRange(0.0, grid.GetPointData().GetVectors().GetMaxNorm())

________________________________
-Universidad Central "Marta Abreu" de Las Villas. http://www.uclv.edu.cu
-Participe en Universidad 2012, del 13 al 17 de febrero de 2012. Habana.Cuba. http://www.congresouniversidad.cu
-Consulte la enciclopedia colaborativa cubana. http://www.ecured.cu/

________________________________
-Universidad Central "Marta Abreu" de Las Villas. http://www.uclv.edu.cu
-Participe en Universidad 2012, del 13 al 17 de febrero de 2012. Habana.Cuba. http://www.congresouniversidad.cu
-Consulte la enciclopedia colaborativa cubana. http://www.ecured.cu/



________________________________
-Universidad Central "Marta Abreu" de Las Villas. http://www.uclv.edu.cu
-Participe en Universidad 2012, del 13 al 17 de febrero de 2012. Habana.Cuba. http://www.congresouniversidad.cu
-Consulte la enciclopedia colaborativa cubana. http://www.ecured.cu/


________________________________
-Universidad Central "Marta Abreu" de Las Villas. http://www.uclv.edu.cu
-Participe en Universidad 2012, del 13 al 17 de febrero de 2012. Habana.Cuba. http://www.congresouniversidad.cu
-Consulte la enciclopedia colaborativa cubana. http://www.ecured.cu/


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