# Development

**URL:** https://discourse.vtk.org/c/development/7.md?page=15

[Latest](https://discourse.vtk.org/latest.md) · [Categories](https://discourse.vtk.org/categories.md) · [Tags](https://discourse.vtk.org/tags.md)

**Page:** 16

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## [How to draw 10000+ object?](https://discourse.vtk.org/t/how-to-draw-10000-object/8438)

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**Author:** [@Ren](https://discourse.vtk.org/u/Ren)\
**Replies:** 35\
**Last updated:** [January 18, 2024, 8:35am UTC](https://discourse.vtk.org/t/how-to-draw-10000-object/8438 "2024-01-18T08:35:46Z")

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Hello, everyone! I have 10000+ objects to draw, everyone can be shown/hided individually, and everyone has its own color, draw each one object using one actor, one mapper, but the performance is bad, how to do?

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## [set opacity using vtkLookupTable](https://discourse.vtk.org/t/set-opacity-using-vtklookuptable/13094)

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**Author:** [@Ren](https://discourse.vtk.org/u/Ren)\
**Replies:** 0\
**Last updated:** [January 18, 2024, 7:57am UTC](https://discourse.vtk.org/t/set-opacity-using-vtklookuptable/13094 "2024-01-18T07:57:32Z")

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I try to use one actor to draw a box with 6 colors, and set opacity 0.5 for one face, I am using setTableValue(index, double rgba\[4\]), but it is can’t work. if the opacity is 0 or 1, it works well.

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## [Rotation Filter](https://discourse.vtk.org/t/rotation-filter/13085)

<div class="topic-metadata">

**Author:** [@Rafael\_Scatena](https://discourse.vtk.org/u/Rafael_Scatena)\
**Replies:** 1\
**Last updated:** [January 17, 2024, 12:35pm UTC](https://discourse.vtk.org/t/rotation-filter/13085 "2024-01-17T12:35:40Z")

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Hello, I created a function to rotate my mesh but it isn’t working. I wanto to rotate the resulting mesh of the smooth discrete marching cubes filter. Thank you, vtkSmartPointer\<vtkPolyData\> RotationFilter::RotateMesh…

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## [vtkProbeLineFilter do not draw some PointData when the dataset do not belong to proc id 0](https://discourse.vtk.org/t/vtkprobelinefilter-do-not-draw-some-pointdata-when-the-dataset-do-not-belong-to-proc-id-0/12947)

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**Author:** [@guillaume\_Peillex](https://discourse.vtk.org/u/guillaume_Peillex)\
**Replies:** 5\
**Last updated:** [January 12, 2024, 4:20pm UTC](https://discourse.vtk.org/t/vtkprobelinefilter-do-not-draw-some-pointdata-when-the-dataset-do-not-belong-to-proc-id-0/12947 "2024-01-12T16:20:26Z")

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Hi all, I am facing a strange situation and would appreciate any help. I’am working in parallel on two MPI threads. I have 4 datasets (each representing a material) that are spread over those two MPI threads. At time …

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## [Atempt to render offscreen using vtkEGLRenderWindow](https://discourse.vtk.org/t/atempt-to-render-offscreen-using-vtkeglrenderwindow/12956)

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**Author:** [@Rafael\_Scatena](https://discourse.vtk.org/u/Rafael_Scatena)\
**Replies:** 2\
**Last updated:** [January 11, 2024, 10:33pm UTC](https://discourse.vtk.org/t/atempt-to-render-offscreen-using-vtkeglrenderwindow/12956 "2024-01-11T22:33:49Z")

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I am trying to render offscreen with EGL but I keep geting segmentation fault. Thank you, std::cerr \<\< "Colours" \<\< std::endl; // Setup offscreen rendering vtkNew\<vtkNamedColors\> colors; …

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## [Problem with CGAL Istotropic remeshing](https://discourse.vtk.org/t/problem-with-cgal-istotropic-remeshing/12581)

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**Author:** [@kimia\_ghodoosi](https://discourse.vtk.org/u/kimia_ghodoosi)\
**Replies:** 12\
**Last updated:** [January 11, 2024, 1:06pm UTC](https://discourse.vtk.org/t/problem-with-cgal-istotropic-remeshing/12581 "2024-01-11T13:06:26Z")

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Hi I have a CGAL Code that works for remeshing but when I want to use the same task in VESPA, it gives me nothing. does anybody else who can help me? the results are shown below: My code in CGAL: My code in VESPA: …

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## [Cannot Open libQt6OpenGLWidgets.so.6](https://discourse.vtk.org/t/cannot-open-libqt6openglwidgets-so-6/13047)

<div class="topic-metadata">

**Author:** [@Rafael\_Scatena](https://discourse.vtk.org/u/Rafael_Scatena)\
**Replies:** 1\
**Last updated:** [January 11, 2024, 10:39am UTC](https://discourse.vtk.org/t/cannot-open-libqt6openglwidgets-so-6/13047 "2024-01-11T10:39:30Z")

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If the message: “error while loading shared libraries: libQt6OpenGLWidgets.so.6: cannot open shared object file: No such file or directory” pops should I reinstall qt? Even if this directory is there… Thank you I searc…

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## [1M of text plotting](https://discourse.vtk.org/t/1m-of-text-plotting/12974)

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**Author:** [@Mesh](https://discourse.vtk.org/u/Mesh)\
**Replies:** 1\
**Last updated:** [January 7, 2024, 10:44pm UTC](https://discourse.vtk.org/t/1m-of-text-plotting/12974 "2024-01-07T22:44:28Z")

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Hi, what is the best approach to plot scalardata as text of vtkunstructuredgrid that contains more than 1M cell ? Thank you

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## [Vtk9.x Cannot used in QQuickFramebufferObject::Renderer \*createRenderer() but vtk8.x can do .](https://discourse.vtk.org/t/vtk9-x-cannot-used-in-qquickframebufferobject-renderer-createrenderer-but-vtk8-x-can-do/9652)

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**Author:** [@edwardAllen](https://discourse.vtk.org/u/edwardAllen)\
**Replies:** 12\
**Last updated:** [January 3, 2024, 6:34pm UTC](https://discourse.vtk.org/t/vtk9-x-cannot-used-in-qquickframebufferobject-renderer-createrenderer-but-vtk8-x-can-do/9652 "2024-01-03T18:34:57Z")

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See below project : nicanor-romero/QtVtk: An integration between Qt Quick Controls 2 and VTK for 3D rendering (github.com) And qCring/QuickVtk: A VTK prototyping application based on QtQuick/QML (github.com) They…

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## [VtkSOADataArrayTemplate Java](https://discourse.vtk.org/t/vtksoadataarraytemplate-java/12954)

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**Author:** [@Kostas\_Politis](https://discourse.vtk.org/u/Kostas_Politis)\
**Replies:** 3\
**Last updated:** [December 28, 2023, 9:52am UTC](https://discourse.vtk.org/t/vtksoadataarraytemplate-java/12954 "2023-12-28T09:52:13Z")

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Hello all, We had some trouble transferring vtkMutliblocks of unstructured grids from c++ to java. Since our grids have vtksoaDataArrays of Doubles they obtain invalid pointers when passed to java. Transforming our arra…

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## [vtkImageViewer2 and slab](https://discourse.vtk.org/t/vtkimageviewer2-and-slab/12975)

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**Author:** [@xjjgjmeng](https://discourse.vtk.org/u/xjjgjmeng)\
**Replies:** 0\
**Last updated:** [December 27, 2023, 1:55pm UTC](https://discourse.vtk.org/t/vtkimageviewer2-and-slab/12975 "2023-12-27T13:55:05Z")

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I use vtkResliceImageViewer or vtkImageViewer2 to display a slice in a dicom sequence. How do I set the thickness and combination of the output slices? Just like vtkImageReslice::SetSlabNumberOfSlices and vtkImageReslice…

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## [I am getting segmentation fault with EGL offscreen rendering window](https://discourse.vtk.org/t/i-am-getting-segmentation-fault-with-egl-offscreen-rendering-window/12970)

<div class="topic-metadata">

**Author:** [@Rafael\_Scatena](https://discourse.vtk.org/u/Rafael_Scatena)\
**Replies:** 1\
**Last updated:** [December 26, 2023, 11:25pm UTC](https://discourse.vtk.org/t/i-am-getting-segmentation-fault-with-egl-offscreen-rendering-window/12970 "2023-12-26T23:25:37Z")

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Here is my code and the error message. Thank you for the assistance. Rafael S. std::cerr \<\< "Colours" \<\< std::endl; vtkNew\<vtkNamedColors\> colors; // Create a sphere vtkNew\<vtkSphereSo…

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## [How to use the vtkFrenetSerretFrame to make a dental panorama, also known as CPR?](https://discourse.vtk.org/t/how-to-use-the-vtkfrenetserretframe-to-make-a-dental-panorama-also-known-as-cpr/8330)

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**Author:** [@JamesHOE](https://discourse.vtk.org/u/JamesHOE)\
**Replies:** 7\
**Last updated:** [December 25, 2023, 6:57am UTC](https://discourse.vtk.org/t/how-to-use-the-vtkfrenetserretframe-to-make-a-dental-panorama-also-known-as-cpr/8330 "2023-12-25T06:57:15Z")

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Hello every one， This is my first post on this forum, Hope you guys can give me some advice， Below are my questions here I was refer to VTK Journal --A Spline-Driven Image Slicer wish to implement Dental panorama Ima…

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## [Implement reader for data file containing an unknown amount of datasets](https://discourse.vtk.org/t/implement-reader-for-data-file-containing-an-unknown-amount-of-datasets/12962)

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**Author:** [@Krzmbrzl](https://discourse.vtk.org/u/Krzmbrzl)\
**Replies:** 6\
**Last updated:** [December 23, 2023, 8:05pm UTC](https://discourse.vtk.org/t/implement-reader-for-data-file-containing-an-unknown-amount-of-datasets/12962 "2023-12-23T20:05:53Z")

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I’m currently working on refactoring the reader for Gaussian cube files in order to address https://gitlab.kitware.com/vtk/vtk/-/issues/18725 and a couple of other shortcomings that I have discovered while going through …

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## [vtkImageDifference does not detect different images](https://discourse.vtk.org/t/vtkimagedifference-does-not-detect-different-images/12935)

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**Author:** [@guillaume\_Peillex](https://discourse.vtk.org/u/guillaume_Peillex)\
**Replies:** 6\
**Last updated:** [December 20, 2023, 1:01pm UTC](https://discourse.vtk.org/t/vtkimagedifference-does-not-detect-different-images/12935 "2023-12-20T13:01:15Z")

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Hi all, In the CI of Themys, our ParaView Branded Application, we use the module Testing.py which makes use of the vtkImageDifference algorithm. It seems that with default configuration this algorithm does not detect t…

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## [Image-based lighting (e.g., PBR) vs shadows](https://discourse.vtk.org/t/image-based-lighting-e-g-pbr-vs-shadows/12835)

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**Author:** [@Sean\_Curtis](https://discourse.vtk.org/u/Sean_Curtis)\
**Replies:** 5\
**Last updated:** [December 18, 2023, 8:53am UTC](https://discourse.vtk.org/t/image-based-lighting-e-g-pbr-vs-shadows/12835 "2023-12-18T08:53:27Z")

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I’ve recently started using the PBR rendering capabilities of VTK and I’ve hit a surprise, specifically, I seem unable to combine shadow maps with environment map lighting. In some ways, the two features seem orthogonal. …

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## [How to use \`vtkprojectPointsToPlane\` to project to a 3D object to a special plane?](https://discourse.vtk.org/t/how-to-use-vtkprojectpointstoplane-to-project-to-a-3d-object-to-a-special-plane/11221)

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**Author:** [@jumbojing](https://discourse.vtk.org/u/jumbojing)\
**Replies:** 10\
**Last updated:** [December 15, 2023, 2:54pm UTC](https://discourse.vtk.org/t/how-to-use-vtkprojectpointstoplane-to-project-to-a-3d-object-to-a-special-plane/11221 "2023-12-15T14:54:27Z")

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I want to use the vtkProjectPointsToPlane to project this object onto a specific plane, but encountered this problem: :point\_down:the 3D object in 3D Slicer: def pd2plaPj(mod, cp= \[0,0,0\], norm=\[0,1,0\]): norm =…

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## [Question About MPI max Numprocs](https://discourse.vtk.org/t/question-about-mpi-max-numprocs/12909)

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**Author:** [@Rafael\_Scatena](https://discourse.vtk.org/u/Rafael_Scatena)\
**Replies:** 2\
**Last updated:** [December 15, 2023, 1:34pm UTC](https://discourse.vtk.org/t/question-about-mpi-max-numprocs/12909 "2023-12-15T13:34:25Z")

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I have build VTK with MPI enabled and mpimaxnumprocs=64. When I build my app I print the value of VTK\_MPI\_NUMPROCS and the value I get is 2. Do somebody know what is the issue? Thank you

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## [Does VTK support 'inverted frustum' projection?](https://discourse.vtk.org/t/does-vtk-support-inverted-frustum-projection/12905)

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**Author:** [@Daan\_Baas](https://discourse.vtk.org/u/Daan_Baas)\
**Replies:** 2\
**Last updated:** [December 15, 2023, 1:30pm UTC](https://discourse.vtk.org/t/does-vtk-support-inverted-frustum-projection/12905 "2023-12-15T13:30:25Z")

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Hi Everyone, I am trying to correctly overlay 3D polydata of organs we obtained from a patient’s MRI onto an X-Ray Fluoroscopy (projection) image of the same person. In X-Ray projection, items closer to the X-Ray source…

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## [Yet another QVTKOpenGLWidget renaming ?](https://discourse.vtk.org/t/yet-another-qvtkopenglwidget-renaming/2602)

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**Author:** [@mwestphal](https://discourse.vtk.org/u/mwestphal)\
**Replies:** 24\
**Last updated:** [March 3, 2020, 3:41am UTC](https://discourse.vtk.org/t/yet-another-qvtkopenglwidget-renaming/2602 "2020-03-03T03:41:23Z")

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Hi Community, With VTK-9 coming, I wonder if we should rename QVTKOpenGLWidget again, as the new version was not so much used after all as it has some specific failings, while it’s only advantage is to support stereo re…

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## [vtkWorldPointPicker does not show updated world coordinates after a Spin (in plane rotation)](https://discourse.vtk.org/t/vtkworldpointpicker-does-not-show-updated-world-coordinates-after-a-spin-in-plane-rotation/12893)

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**Author:** [@Namdhari](https://discourse.vtk.org/u/Namdhari)\
**Replies:** 0\
**Last updated:** [December 13, 2023, 8:38am UTC](https://discourse.vtk.org/t/vtkworldpointpicker-does-not-show-updated-world-coordinates-after-a-spin-in-plane-rotation/12893 "2023-12-13T08:38:00Z")

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Hello, I am using vtkWorldPointPicker as follows: auto world\_point\_picker = vtkWorldPointPicker::New(); world\_point\_picker-\>Pick(position\_x, position\_y, 0.0, this-\>CurrentRenderer); auto picked\_position = world\_point\_p…

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## [I have a question about the control of the polygon.](https://discourse.vtk.org/t/i-have-a-question-about-the-control-of-the-polygon/12882)

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**Author:** [@ManInTheSouth](https://discourse.vtk.org/u/ManInTheSouth)\
**Replies:** 3\
**Last updated:** [December 13, 2023, 2:05am UTC](https://discourse.vtk.org/t/i-have-a-question-about-the-control-of-the-polygon/12882 "2023-12-13T02:05:58Z")

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private void renderWindowControl1\_Load(object sender, EventArgs e) { sphere.SetThetaResolution(8); sphere.SetPhiResolution(20); shrink.SetInputConnection(sphere.GetOutputPort()); shrink.SetShrinkFactor(0.9); mapper…

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## [Using VTK to implement particle transport grometry (question about celllocator,IntersectWithLine)](https://discourse.vtk.org/t/using-vtk-to-implement-particle-transport-grometry-question-about-celllocator-intersectwithline/12887)

<div class="topic-metadata">

**Author:** [@Rafael\_Scatena](https://discourse.vtk.org/u/Rafael_Scatena)\
**Replies:** 0\
**Last updated:** [December 12, 2023, 9:14pm UTC](https://discourse.vtk.org/t/using-vtk-to-implement-particle-transport-grometry-question-about-celllocator-intersectwithline/12887 "2023-12-12T21:14:24Z")

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I am building a geometry module to my particle transport program. Contrary to rendering and visualization, particle transport moves the particle a little bit each time and check if it has crossed the mesh. My question i…

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## [Is there a bucket point interesection test?](https://discourse.vtk.org/t/is-there-a-bucket-point-interesection-test/12878)

<div class="topic-metadata">

**Author:** [@Rafael\_Scatena](https://discourse.vtk.org/u/Rafael_Scatena)\
**Replies:** 1\
**Last updated:** [December 11, 2023, 10:37pm UTC](https://discourse.vtk.org/t/is-there-a-bucket-point-interesection-test/12878 "2023-12-11T22:37:14Z")

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I am using celllocator and would like to know if I can load cells from a bucket a particular point is at

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## [Proposal: Update \`vtkPythonCommand::Execute\` to support custom event](https://discourse.vtk.org/t/proposal-update-vtkpythoncommand-execute-to-support-custom-event/12866)

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**Author:** [@jcfr](https://discourse.vtk.org/u/jcfr)\
**Replies:** 1\
**Last updated:** [December 7, 2023, 8:33pm UTC](https://discourse.vtk.org/t/proposal-update-vtkpythoncommand-execute-to-support-custom-event/12866 "2023-12-07T20:33:52Z")

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The current implementation vtkPythonCommand::Execute does not support custom event. See Test Case below. Problem The issue is that vtkPythonCommand::GetStringFromEventId\[1\] (used in vtkPythonCommand::Execute\[2\]) returns…

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## [Can't visualize with open-gl on x-client](https://discourse.vtk.org/t/cant-visualize-with-open-gl-on-x-client/12840)

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**Author:** [@Rafael\_Scatena](https://discourse.vtk.org/u/Rafael_Scatena)\
**Replies:** 5\
**Last updated:** [December 5, 2023, 3:56pm UTC](https://discourse.vtk.org/t/cant-visualize-with-open-gl-on-x-client/12840 "2023-12-05T15:56:58Z")

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– Found OpenGL: /usr/lib/x86\_64-linux-gnu/libOpenGL.so found components: OpenGL GLX – Found OpenGL: /usr/lib/x86\_64-linux-gnu/libOpenGL.so – OpenGL found: – Version: – Include Path: /usr/include – Libraries: …

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## [Can't Add Outline on vtk Bezier](https://discourse.vtk.org/t/cant-add-outline-on-vtk-bezier/12850)

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**Author:** [@Loic\_Azegha](https://discourse.vtk.org/u/Loic_Azegha)\
**Replies:** 0\
**Last updated:** [December 5, 2023, 2:43pm UTC](https://discourse.vtk.org/t/cant-add-outline-on-vtk-bezier/12850 "2023-12-05T14:43:18Z")

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Hello I tried to add the outline on my vtk bezier hexahedron vtkActor actor= new vtkActor(); vtkActor actorBorder= new vtkActor(); vtkUnstructuredGrid ugrid= new vtkUnstructuredGrid(); ugrid.SetPoints(points);…

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## [Rubberband Pick](https://discourse.vtk.org/t/rubberband-pick/12837)

<div class="topic-metadata">

**Author:** [@totte\_karlsson](https://discourse.vtk.org/u/totte_karlsson)\
**Replies:** 0\
**Last updated:** [December 4, 2023, 9:53pm UTC](https://discourse.vtk.org/t/rubberband-pick/12837 "2023-12-04T21:53:00Z")

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Hello, We are doing a rubberband pick on simple PolyData, Polylines. The rubberbandpick code is using the code from the Rubberbandpick example here: https://examples.vtk.org/site/Java/Interaction/RubberBandPick/ In gen…

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## [Can't write polydata to file...](https://discourse.vtk.org/t/cant-write-polydata-to-file/12836)

<div class="topic-metadata">

**Author:** [@Rafael\_Scatena](https://discourse.vtk.org/u/Rafael_Scatena)\
**Replies:** 1\
**Last updated:** [December 4, 2023, 8:49pm UTC](https://discourse.vtk.org/t/cant-write-polydata-to-file/12836 "2023-12-04T20:49:16Z")

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Hi there. Can’t make my VTK module write polydata. Any help welcome. Thanks. /usr/bin/ld: CMakeFiles/createmesh.dir/MeshWriter.cxx.o: undefined reference to symbol “\_ZN9vtkWriter12SetInputDataEP13vtkDataObject” /usr/bi…

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## [VTK+PCL Viewer BOXwidget2 is not show](https://discourse.vtk.org/t/vtk-pcl-viewer-boxwidget2-is-not-show/12830)

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**Author:** [@bowen\_zhu](https://discourse.vtk.org/u/bowen_zhu)\
**Replies:** 0\
**Last updated:** [December 2, 2023, 7:37am UTC](https://discourse.vtk.org/t/vtk-pcl-viewer-boxwidget2-is-not-show/12830 "2023-12-02T07:37:17Z")

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this is my code class QVTKWindow : public QVTKOpenGLNativeWidget impl-\>renderer = vtkSmartPointer::New();/ impl-\>renderWindow = vtkSmartPointer::New(); impl-\>renderWindow-\>AddRenderer(impl-\>renderer); impl-\>view…

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