The structured grid I have only contains vector data. I guess this may be the reason why streamlines are not colored because no scalar data is available for color mapping<div><br></div><div>I attached my source code. Can someone help me out? Thanks a lot</div>
<div><br></div><div>Yifei</div><div><div><br></div></div><div><br></div><div><div class="gmail_quote">On Wed, Nov 9, 2011 at 1:50 PM, Yifei Li <span dir="ltr"><<a href="mailto:yifli82@gmail.com">yifli82@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">Marcelino,<div><br></div><div>Thank you for your help, but my problem persists.</div><div><br></div><div>Setting a lookup table failed (although, like you said, it's not necessary since vtkPolyDataMappe already has one).</div>
<div><br></div><div>Then I tried vtkAssignAttribute, it does not work for me either. I guess <span style="color:rgb(31, 73, 125);font-size:15px">aa.Assign("SCALARS", "VECTORS", "POINT_DATA") </span>means treat the point data (velocity vectors) in the grid as scalars, which makes sense to me.</div>
<div><br></div><div>I took a look at another example Examples/VisualizationAlgorithms/Python/OfficeTube.py, the only thing that's relevant to streamline coloring is</div><div><br></div><div>mapStreamTube.SetScalarRange(reader.GetOutput().GetPointData().GetScalars().GetRange()), where mapStreamTube is a PolyDataMapper</div>
<div><br></div><div><br></div><div>What I have in my program is very similar to the above:</div><div>streamMapper.SetScalarRange(0.0, grid.GetPointData().GetVectors().GetMaxNorm())</div><div><br></div><div>I print out the the value of GetMaxNorm() and it is not zero.</div>
<div><br></div><div><br><br><div class="gmail_quote"><div><div></div><div class="h5">On Wed, Nov 9, 2011 at 11:47 AM, Marcelino Rodriguez Cancio <span dir="ltr"><<a href="mailto:marcelinorc@uclv.edu.cu" target="_blank">marcelinorc@uclv.edu.cu</a>></span> wrote:<br>
</div></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div></div><div class="h5">
<div lang="ES-DO" link="blue" vlink="purple">
<div>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;color:#1F497D">Yifei,<u></u><u></u></span></p><div>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;color:#1F497D"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;color:#1F497D">>></span><span lang="EN-US"> no lookup table is set for the streamMapper. Why?<u></u><u></u></span></p>
</div><p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;color:#1F497D">Because vtkPolyDataMapper has a default vtkLookUpTable.<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;color:#1F497D"> <u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;color:#1F497D">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:<u></u><u></u></span></p><div>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;color:#1F497D"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;color:#1F497D">aa = vtkAssignAttribute()
<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;color:#1F497D">aa. SetInput(grid)<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;color:#1F497D">#Not so sure how to do this in Python since I have only worked in C++ and TCL<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;color:#1F497D">aa.Assign("SCALARS", "VECTORS", "POINT_DATA")<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;color:#1F497D"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;color:#1F497D">streamer.SetInputConnection(aa.GetOutputPort())<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;color:#1F497D"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;color:#1F497D"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;color:#1F497D">Hope it helps<u></u><u></u></span></p>
</div><p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;color:#1F497D">Marcelino<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"><u></u> <u></u></span></p>
<div>
<div style="border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm 0cm 0cm">
<p class="MsoNormal"><b><span lang="ES" style="font-size:10.0pt">De:</span></b><span lang="ES" style="font-size:10.0pt"> <a href="mailto:vtkusers-bounces@vtk.org" target="_blank">vtkusers-bounces@vtk.org</a> [mailto:<a href="mailto:vtkusers-bounces@vtk.org" target="_blank">vtkusers-bounces@vtk.org</a>]
<b>En nombre de </b>Yifei Li</span></p><div><br>
<b>Enviado el:</b> miércoles, 09 de noviembre de 2011 10:07 a.m.<br>
<b>Para:</b> <a href="mailto:vtkusers@vtk.org" target="_blank">vtkusers@vtk.org</a><br>
</div><b>Asunto:</b> Re: [vtkusers] all my streamlines are in white :(<u></u><u></u><p></p>
</div>
</div><div><div></div><div>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">Marcelino, <u></u><u></u></p>
<div>
<p class="MsoNormal"><u></u> <u></u></p>
</div>
<div>
<p class="MsoNormal">Thank you. I'll try you suggestion.<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"><u></u> <u></u></p>
</div>
<div>
<p class="MsoNormal">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?<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal" style="margin-bottom:12.0pt">Yifei<u></u><u></u></p>
<div>
<p class="MsoNormal">On Wed, Nov 9, 2011 at 8:16 AM, Marcelino Rodriguez Cancio <<a href="mailto:marcelinorc@uclv.edu.cu" target="_blank">marcelinorc@uclv.edu.cu</a>> wrote:<u></u><u></u></p>
<div>
<div>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;color:#1F497D">Yifei:</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;color:#1F497D"> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;color:#1F497D">I think you need to add a vtkLookUpTable:</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;color:#1F497D"> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;color:#1F497D">lut = vtkLookupTable()</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;color:#1F497D">lut.SetHueRange(667, 0.0)</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;color:#1F497D">lut.Build()</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;color:#1F497D"> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;color:#1F497D">streamMapper.SetLookupTable(lut)</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;color:#1F497D"> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;color:#1F497D">Greetings</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;color:#1F497D">Marcelino</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;color:#1F497D"> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;color:#1F497D"> </span><u></u><u></u></p>
<div>
<div style="border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm 0cm 0cm">
<p class="MsoNormal"><b><span lang="ES" style="font-size:10.0pt">De:</span></b><span lang="ES" style="font-size:10.0pt">
<a href="mailto:vtkusers-bounces@vtk.org" target="_blank">vtkusers-bounces@vtk.org</a> [mailto:<a href="mailto:vtkusers-bounces@vtk.org" target="_blank">vtkusers-bounces@vtk.org</a>]
<b>En nombre de </b>Yifei Li<br>
<b>Enviado el:</b> martes, 08 de noviembre de 2011 08:24 p.m.<br>
<b>Para:</b> <a href="mailto:vtkusers@vtk.org" target="_blank">vtkusers@vtk.org</a><br>
<b>Asunto:</b> [vtkusers] all my streamlines are in white :(</span><u></u><u></u></p>
</div>
</div>
<div>
<div>
<p class="MsoNormal"> <u></u><u></u></p>
<p class="MsoNormal">Hi all,
<u></u><u></u></p>
<div>
<p class="MsoNormal"> <u></u><u></u></p>
</div>
<div>
<p class="MsoNormal">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<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"> <u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"># vector field data<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal">grid = vtkStructuredGrid()<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal">grid.SetPoints(points)<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal">grid.GetPointData().SetVectors(vectors)<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"> <u></u><u></u></p>
</div>
<div>
<p class="MsoNormal">....<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal">streamer = vtkStreamTracer()<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal">...<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"># show streamlines using ribbon<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal">rf = vtkRibbonFilter()<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal">rf.SetInputConnection(streamer.GetOutputPort())<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"> <u></u><u></u></p>
</div>
<div>
<p class="MsoNormal">streamMapper = vtkPolyDataMapper()<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal">streamMapper.SetInputConnection(rf.GetOutputPort())<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"> <u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"># I thought the following lines should make it <u></u><u></u></p>
</div>
<div>
<p class="MsoNormal">streamMapper.ScalarVisibilityOn()<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal">streamMapper.SetScalarRange(0.0, grid.GetPointData().GetVectors().GetMaxNorm())<u></u><u></u></p>
</div>
<p class="MsoNormal"> <u></u><u></u></p>
</div>
</div>
<div class="MsoNormal" align="center" style="text-align:center">
<hr size="2" width="100%" align="center">
</div>
<p class="MsoNormal" style="margin-bottom:12.0pt"><span style="font-size:7.5pt;color:gray">-Universidad Central "Marta Abreu" de Las Villas.
<a href="http://www.uclv.edu.cu" target="_blank">http://www.uclv.edu.cu</a><br>
-Participe en Universidad 2012, del 13 al 17 de febrero de 2012. Habana.Cuba. <a href="http://www.congresouniversidad.cu" target="_blank">
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-Consulte la enciclopedia colaborativa cubana. <a href="http://www.ecured.cu/" target="_blank">
http://www.ecured.cu/</a></span><u></u><u></u></p>
</div>
<p class="MsoNormal"><u></u> <u></u></p>
<div class="MsoNormal" align="center" style="text-align:center">
<hr size="2" width="100%" align="center">
</div>
<p class="MsoNormal" style="margin-bottom:12.0pt"><span style="font-size:7.5pt;color:gray">-Universidad Central "Marta Abreu" de Las Villas.
<a href="http://www.uclv.edu.cu" target="_blank">http://www.uclv.edu.cu</a><br>
-Participe en Universidad 2012, del 13 al 17 de febrero de 2012. Habana.Cuba. <a href="http://www.congresouniversidad.cu" target="_blank">
http://www.congresouniversidad.cu</a><br>
-Consulte la enciclopedia colaborativa cubana. <a href="http://www.ecured.cu/" target="_blank">
http://www.ecured.cu/</a><br>
<br>
</span><u></u><u></u></p>
</div>
</div>
<p class="MsoNormal"><u></u> <u></u></p>
</div>
<p class="MsoNormal"><u></u> <u></u></p>
<div class="MsoNormal" align="center" style="text-align:center">
<hr size="2" width="100%" align="center">
</div>
<p class="MsoNormal" style="margin-bottom:12.0pt"><span style="font-size:7.5pt;color:gray">-Universidad Central "Marta Abreu" de Las Villas. <a href="http://www.uclv.edu.cu" target="_blank">http://www.uclv.edu.cu</a><br>
-Participe en Universidad 2012, del 13 al 17 de febrero de 2012. Habana.Cuba. <a href="http://www.congresouniversidad.cu" target="_blank">http://www.congresouniversidad.cu</a><br>
-Consulte la enciclopedia colaborativa cubana. <a href="http://www.ecured.cu/" target="_blank">http://www.ecured.cu/</a><br>
<br>
</span><u></u><u></u></p>
</div></div></div><div><div></div><div>
<br>
<hr>
<font face="Arial" color="Gray" size="1">-Universidad Central "Marta Abreu" de Las Villas. <a href="http://www.uclv.edu.cu" target="_blank">http://www.uclv.edu.cu</a><br>
-Participe en Universidad 2012, del 13 al 17 de febrero de 2012. Habana.Cuba. <a href="http://www.congresouniversidad.cu" target="_blank">http://www.congresouniversidad.cu</a><br>
-Consulte la enciclopedia colaborativa cubana. <a href="http://www.ecured.cu/" target="_blank">http://www.ecured.cu/</a><br>
<br>
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