# Support

**URL:** https://discourse.vtk.org/c/support/6.md?page=22

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

**Page:** 23

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## [Extruding a polygon into another or connecting polygons](https://discourse.vtk.org/t/extruding-a-polygon-into-another-or-connecting-polygons/6969)

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**Author:** [@Andrea\_Gavana](https://discourse.vtk.org/u/Andrea_Gavana)\
**Replies:** 13\
**Last updated:** [July 23, 2024, 3:45am UTC](https://discourse.vtk.org/t/extruding-a-polygon-into-another-or-connecting-polygons/6969 "2024-07-23T03:45:44Z")

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Dear VTK Users, I am in a situation where I have a series of ellipses (discretized as polygons with about 20 points) one after the other and I would like to “connect” them in order to create a “tube”-like surface (exter…

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## [HardwareSelector examples](https://discourse.vtk.org/t/hardwareselector-examples/13776)

<div class="topic-metadata">

**Author:** [@whereismymoney](https://discourse.vtk.org/u/whereismymoney)\
**Replies:** 1\
**Last updated:** [July 22, 2024, 9:29pm UTC](https://discourse.vtk.org/t/hardwareselector-examples/13776 "2024-07-22T21:29:53Z")

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The vtk.js HardwareSelector example is truly amazing: link Is there Python or C++ version of this available? The Python HardwareSelector example is a great example, but does not have all of the features of the example…

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## [How to handle very large and very small objects in a scene?](https://discourse.vtk.org/t/how-to-handle-very-large-and-very-small-objects-in-a-scene/14277)

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**Author:** [@rexthor](https://discourse.vtk.org/u/rexthor)\
**Replies:** 1\
**Last updated:** [July 22, 2024, 8:40pm UTC](https://discourse.vtk.org/t/how-to-handle-very-large-and-very-small-objects-in-a-scene/14277 "2024-07-22T20:40:29Z")

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There is a class I want to use: vtkEarthSource, put on top of a crude texture map of the earth … and I want to also show something like a satellite, where the earth is realistically sized (for the horizon) and the satell…

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## [Error: no override is found for 'vtkPolyDataMapper'](https://discourse.vtk.org/t/error-no-override-is-found-for-vtkpolydatamapper/14270)

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**Author:** [@Gib\_Bogle](https://discourse.vtk.org/u/Gib_Bogle)\
**Replies:** 3\
**Last updated:** [July 22, 2024, 2:32pm UTC](https://discourse.vtk.org/t/error-no-override-is-found-for-vtkpolydatamapper/14270 "2024-07-22T14:32:05Z")

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I have built vtk-8.2.0, and have compiled a simple test program, cylinder.cxx. When I run it, a window pops up for a couple of seconds, with this message (which I managed to capture on my phone with some difficulty): G…

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## [Paraview has nice lookup tables, is there an easy way to use them in VTK?](https://discourse.vtk.org/t/paraview-has-nice-lookup-tables-is-there-an-easy-way-to-use-them-in-vtk/14260)

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**Author:** [@rexthor](https://discourse.vtk.org/u/rexthor)\
**Replies:** 6\
**Last updated:** [July 22, 2024, 10:07am UTC](https://discourse.vtk.org/t/paraview-has-nice-lookup-tables-is-there-an-easy-way-to-use-them-in-vtk/14260 "2024-07-22T10:07:14Z")

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Paraview has a nice set of preset lookup tables, is there any way to use those in VTK?

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## [I want to publish VTK to Android (Qt Quick)](https://discourse.vtk.org/t/i-want-to-publish-vtk-to-android-qt-quick/14060)

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**Author:** [@Roque](https://discourse.vtk.org/u/Roque)\
**Replies:** 15\
**Last updated:** [July 21, 2024, 1:11pm UTC](https://discourse.vtk.org/t/i-want-to-publish-vtk-to-android-qt-quick/14060 "2024-07-21T13:11:03Z")

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Hello everyone, when I compiled the vtk-android (arm64-v8a NDK 27.0.11902837) static library, I was prompted to replace ALooper\_pollAll() with ALooper\_pollOnce(), and I did so and compiled successfully. Now I want to pu…

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## [Best way to set the mapper scalar range for viewing?](https://discourse.vtk.org/t/best-way-to-set-the-mapper-scalar-range-for-viewing/14261)

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**Author:** [@rexthor](https://discourse.vtk.org/u/rexthor)\
**Replies:** 5\
**Last updated:** [July 19, 2024, 11:43pm UTC](https://discourse.vtk.org/t/best-way-to-set-the-mapper-scalar-range-for-viewing/14261 "2024-07-19T23:43:27Z")

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I tried to distill this down to just one short script. I have attached a temperature array to a vtkPolyData, and I have constructed a vtkColorLookupFunction to go along with it. If my “Temperature” array is in \[0, 1\], e…

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## [How to render a box that marks the camera's view](https://discourse.vtk.org/t/how-to-render-a-box-that-marks-the-cameras-view/14257)

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**Author:** [@dbtruong](https://discourse.vtk.org/u/dbtruong)\
**Replies:** 2\
**Last updated:** [July 19, 2024, 10:08pm UTC](https://discourse.vtk.org/t/how-to-render-a-box-that-marks-the-cameras-view/14257 "2024-07-19T22:08:32Z")

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Hello all, I want to render a box to visualize the camera’s perspective like the image below: Is there any way to do that? Thanks.

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## [Why would vtkXMLPolyDataReader not also read scalar arrays?](https://discourse.vtk.org/t/why-would-vtkxmlpolydatareader-not-also-read-scalar-arrays/14259)

<div class="topic-metadata">

**Author:** [@rexthor](https://discourse.vtk.org/u/rexthor)\
**Replies:** 1\
**Last updated:** [July 19, 2024, 2:04pm UTC](https://discourse.vtk.org/t/why-would-vtkxmlpolydatareader-not-also-read-scalar-arrays/14259 "2024-07-19T14:04:30Z")

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I don’t often use the visualization pipeline in VTK, so sorry if this is silly. I have a datafile that has a “Temperature” array in point data - I can see it in ParaVew, but when I read it in via a Python script, no arr…

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## [Errors building vtkGUISupportQt](https://discourse.vtk.org/t/errors-building-vtkguisupportqt/14111)

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**Author:** [@gib](https://discourse.vtk.org/u/gib)\
**Replies:** 14\
**Last updated:** [July 19, 2024, 6:53am UTC](https://discourse.vtk.org/t/errors-building-vtkguisupportqt/14111 "2024-07-19T06:53:04Z")

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I am building VTK 8.2.0 with Qt 5.12.12, using VS 2019. The build for vtkGUISupportQt fails with 27 errors in the compilation of QVTKOpenGLwidget.cxx. It is not obvious to me what the basic problem is, but many of the …

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## [Troubleshooting a render window not showing up.](https://discourse.vtk.org/t/troubleshooting-a-render-window-not-showing-up/14256)

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**Author:** [@rexthor](https://discourse.vtk.org/u/rexthor)\
**Replies:** 2\
**Last updated:** [July 18, 2024, 7:10pm UTC](https://discourse.vtk.org/t/troubleshooting-a-render-window-not-showing-up/14256 "2024-07-18T19:10:38Z")

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I usually output to file, so if this is obvious, my apologies. I can copy-paste this example, and it works just fine: a window pops up with a cone in it. I tried to simplify it a bit and run it, and this code exits imme…

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## [Is there a better way to reduce the time spent on Render？](https://discourse.vtk.org/t/is-there-a-better-way-to-reduce-the-time-spent-on-render/14242)

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**Author:** [@jie\_baoer](https://discourse.vtk.org/u/jie_baoer)\
**Replies:** 9\
**Last updated:** [July 18, 2024, 3:23am UTC](https://discourse.vtk.org/t/is-there-a-better-way-to-reduce-the-time-spent-on-render/14242 "2024-07-18T03:23:22Z")

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I initialize the vtkUnstructuredGrid object with the following code. The test model has about 1 million VTK\_HEXAHEDRON cells. When executing vtkRenderer-\>Render(), it takes about 10 seconds.Is there a better way to reduc…

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## [Am I misunderstanding how VTK uses vtkInformation in pipelines?](https://discourse.vtk.org/t/am-i-misunderstanding-how-vtk-uses-vtkinformation-in-pipelines/14248)

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**Author:** [@scotsman60](https://discourse.vtk.org/u/scotsman60)\
**Replies:** 4\
**Last updated:** [July 17, 2024, 4:29pm UTC](https://discourse.vtk.org/t/am-i-misunderstanding-how-vtk-uses-vtkinformation-in-pipelines/14248 "2024-07-17T16:29:45Z")

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Hello!!! I’m trying to use vtkInformation to share “metadata” between items in a vtk pipeline. I’m pretty comfortable setting/getting the keys, values etc., but I’ve demonstrated some behavior that surprised me and I’d …

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## [Draw an actor always on top of the secene.](https://discourse.vtk.org/t/draw-an-actor-always-on-top-of-the-secene/11396)

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**Author:** [@DFlyer](https://discourse.vtk.org/u/DFlyer)\
**Replies:** 6\
**Last updated:** [July 17, 2024, 4:23pm UTC](https://discourse.vtk.org/t/draw-an-actor-always-on-top-of-the-secene/11396 "2024-07-17T16:23:38Z")

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Little context I pick faces of polydata with a custom interactor style and want to display as a highlighted. To do this I create a temporary actor with different color, larger line width, reduce opacity on other actors …

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## [Segmentation fault happens in vtkAlgorithm::Update when calling vtkXMLPStructuredGridWriter Update()](https://discourse.vtk.org/t/segmentation-fault-happens-in-vtkalgorithm-update-when-calling-vtkxmlpstructuredgridwriter-update/14236)

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**Author:** [@cheapmeow](https://discourse.vtk.org/u/cheapmeow)\
**Replies:** 3\
**Last updated:** [July 15, 2024, 1:42pm UTC](https://discourse.vtk.org/t/segmentation-fault-happens-in-vtkalgorithm-update-when-calling-vtkxmlpstructuredgridwriter-update/14236 "2024-07-15T13:42:49Z")

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I have a VTS Writer using vtkXMLPStructuredGridWriter. The program crash and reports Segmentation fault in Update(). Most of my code comes from https://stackoverflow.com/questions/24123432/composing-vtk-file-from-multip…

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## [How can i get Color data from "AppendedData" format in vtp files](https://discourse.vtk.org/t/how-can-i-get-color-data-from-appendeddata-format-in-vtp-files/14214)

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**Author:** [@Mt-Youya](https://discourse.vtk.org/u/Mt-Youya)\
**Replies:** 0\
**Last updated:** [July 12, 2024, 7:37am UTC](https://discourse.vtk.org/t/how-can-i-get-color-data-from-appendeddata-format-in-vtp-files/14214 "2024-07-12T07:37:53Z")

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user-appendedData.vtp I cant find colors dataArray in this file, but vtk.js can loaded this file with colors dataArray. And Mesh\_Labeler can loaded this file with colors dataArray also. How can i get Color data from “A…

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## [Is it a bug in vtkMergePoint of Python?](https://discourse.vtk.org/t/is-it-a-bug-in-vtkmergepoint-of-python/13953)

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**Author:** [@altair0985](https://discourse.vtk.org/u/altair0985)\
**Replies:** 3\
**Last updated:** [July 11, 2024, 3:58pm UTC](https://discourse.vtk.org/t/is-it-a-bug-in-vtkmergepoint-of-python/13953 "2024-07-11T15:58:46Z")

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I have a point set, and I want to insert new point which don’t duplication. So I used vtkMergePoints, but something went wrong, new point overwrite the exist point rather than added. Code is follow: ## Initial point se…

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## [VTK 9.3.0 MPI Initializing Error Intel Compilers 2024](https://discourse.vtk.org/t/vtk-9-3-0-mpi-initializing-error-intel-compilers-2024/14193)

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**Author:** [@hveng](https://discourse.vtk.org/u/hveng)\
**Replies:** 0\
**Last updated:** [July 9, 2024, 1:34pm UTC](https://discourse.vtk.org/t/vtk-9-3-0-mpi-initializing-error-intel-compilers-2024/14193 "2024-07-09T13:34:32Z")

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Dear VTK developers, we have encountered problems with the MPI InitializeCommunicator calls in VTK 9.3.0 when compiling with the newest Intel compilers (l\_HPCKit\_p\_2024.2.0.635\_offline.sh). The building and installatio…

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## [Move the camera's target away from center of view](https://discourse.vtk.org/t/move-the-cameras-target-away-from-center-of-view/14174)

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**Author:** [@LarryK19](https://discourse.vtk.org/u/LarryK19)\
**Replies:** 1\
**Last updated:** [July 9, 2024, 1:06pm UTC](https://discourse.vtk.org/t/move-the-cameras-target-away-from-center-of-view/14174 "2024-07-09T13:06:56Z")

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In my app the camera’s target is directly in the center of the VTK renderwindow. Is there a way to move the camera’s target to display offset from the center of the 3d view? Say 10 percent to the right and down.

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## [Measuring the average discrete gaussian and mean curvature of a model with vtk in python?](https://discourse.vtk.org/t/measuring-the-average-discrete-gaussian-and-mean-curvature-of-a-model-with-vtk-in-python/14168)

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**Author:** [@Gregory](https://discourse.vtk.org/u/Gregory)\
**Replies:** 6\
**Last updated:** [July 9, 2024, 6:18am UTC](https://discourse.vtk.org/t/measuring-the-average-discrete-gaussian-and-mean-curvature-of-a-model-with-vtk-in-python/14168 "2024-07-09T06:18:02Z")

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Hi, I am trying to calculate the mean and gaussian curvature across the surface of the model and then obtain the array of the values for every point and run some simple statistics on the array for mean, median, std, etc.…

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## [vtkMultiBlockDataSet and vtkMultiBlockVolumeMapper...](https://discourse.vtk.org/t/vtkmultiblockdataset-and-vtkmultiblockvolumemapper/14166)

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**Author:** [@codeling](https://discourse.vtk.org/u/codeling)\
**Replies:** 2\
**Last updated:** [July 8, 2024, 8:36pm UTC](https://discourse.vtk.org/t/vtkmultiblockdataset-and-vtkmultiblockvolumemapper/14166 "2024-07-08T20:36:38Z")

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I’m trying to use vtkMultiBlockVolumeMapper to render a vtkMultiBlockDataSet. According to the docs of vtkMultiBlockVolumeMapper: vtkMultiBlockVolumeMapper renders vtkMultiBlockDataSet instances containing vtkImageDat…

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## [vtkScalarBarWidget resizing](https://discourse.vtk.org/t/vtkscalarbarwidget-resizing/14163)

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**Author:** [@Mordrago](https://discourse.vtk.org/u/Mordrago)\
**Replies:** 2\
**Last updated:** [July 8, 2024, 6:29am UTC](https://discourse.vtk.org/t/vtkscalarbarwidget-resizing/14163 "2024-07-08T06:29:19Z")

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Hello! I want to resize, change position and change text size of my vtkScalarBarWidget but my code not works. Any tips why? I using QVTKRenderWindowInteractor btw. self.scalar\_bar = vtkScalarBarActor() self.scalar\_bar\_w…

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## [Need Support to display smooth Surface with Interactive Cutting through Model](https://discourse.vtk.org/t/need-support-to-display-smooth-surface-with-interactive-cutting-through-model/14146)

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**Author:** [@Tom\_Schulcz](https://discourse.vtk.org/u/Tom_Schulcz)\
**Replies:** 2\
**Last updated:** [July 4, 2024, 10:09pm UTC](https://discourse.vtk.org/t/need-support-to-display-smooth-surface-with-interactive-cutting-through-model/14146 "2024-07-04T22:09:37Z")

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Hello together, I wrote a small viewing application with vtk and now want to have a smooth display for curved surfaces of my dataset (UnstructuredGrid) which was loaded from a stl-file. I also want to be able to cut th…

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## [Read or split large vtk file for paraview post-processing](https://discourse.vtk.org/t/read-or-split-large-vtk-file-for-paraview-post-processing/14157)

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**Author:** [@ShineSun](https://discourse.vtk.org/u/ShineSun)\
**Replies:** 4\
**Last updated:** [July 4, 2024, 12:39am UTC](https://discourse.vtk.org/t/read-or-split-large-vtk-file-for-paraview-post-processing/14157 "2024-07-04T00:39:52Z")

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Hello community and everyone, Thank you for the powerful tool VTK for scientific data processing. I use Paraview to display my computational fluid dynamics(CFD) data and it really helps me. Now I encounter a problem for…

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## [Which filter is the perfect match for gum deformation used in dental solution](https://discourse.vtk.org/t/which-filter-is-the-perfect-match-for-gum-deformation-used-in-dental-solution/14094)

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**Author:** [@Jimmy\_Vo](https://discourse.vtk.org/u/Jimmy_Vo)\
**Replies:** 3\
**Last updated:** [July 2, 2024, 7:36pm UTC](https://discourse.vtk.org/t/which-filter-is-the-perfect-match-for-gum-deformation-used-in-dental-solution/14094 "2024-07-02T19:36:01Z")

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Hi everyone, I am very new to vtk, I am looking for an algorithm for geometric deformation, specifically applicable to dental treatment. The problem is that I have an upper teeth in the form of a 3D model (.STL or .PLY …

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## [vtkExodusIIWriter / Side Set Example](https://discourse.vtk.org/t/vtkexodusiiwriter-side-set-example/9875)

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**Author:** [@raungst](https://discourse.vtk.org/u/raungst)\
**Replies:** 3\
**Last updated:** [July 2, 2024, 4:54am UTC](https://discourse.vtk.org/t/vtkexodusiiwriter-side-set-example/9875 "2024-07-02T04:54:59Z")

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Hello, I’m trying to write out a model as Exodus II and want to include side set and node set information in it. Is this possible and are there any examples around? Looking at the help, it looks like it is possible with…

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## [VTK files to ExodusII](https://discourse.vtk.org/t/vtk-files-to-exodusii/14148)

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**Author:** [@Mhamad\_Mahdi\_Alloush](https://discourse.vtk.org/u/Mhamad_Mahdi_Alloush)\
**Replies:** 1\
**Last updated:** [July 1, 2024, 2:02pm UTC](https://discourse.vtk.org/t/vtk-files-to-exodusii/14148 "2024-07-01T14:02:20Z")

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Hi, I have a vtk file containing an unstructured grid, in addition to a set of other vtk files containing the grid’s boundary information as polydata (each boundary has a file on its own). I simply need to convert this …

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## [I conducted the following tests regarding VTK's support for UTF8 encoded Chinese paths](https://discourse.vtk.org/t/i-conducted-the-following-tests-regarding-vtks-support-for-utf8-encoded-chinese-paths/14136)

<div class="topic-metadata">

**Author:** [@realwhzc](https://discourse.vtk.org/u/realwhzc)\
**Replies:** 6\
**Last updated:** [July 1, 2024, 2:55am UTC](https://discourse.vtk.org/t/i-conducted-the-following-tests-regarding-vtks-support-for-utf8-encoded-chinese-paths/14136 "2024-07-01T02:55:00Z")

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vtkDataSetReader ✓ vtkOBJReader ✓ vtkSTLReader ✓ vtkOpenFOAMReader : can update but get 0 block vtkTecplotReader : can update but get 0 block vtkCGNSReader : There is no problem with the individual CGNS files, but f…

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## [wglMakeCurrent failed in MakeCurrent() happens every time the window is called to render](https://discourse.vtk.org/t/wglmakecurrent-failed-in-makecurrent-happens-every-time-the-window-is-called-to-render/14143)

<div class="topic-metadata">

**Author:** [@Jakes\_Marais](https://discourse.vtk.org/u/Jakes_Marais)\
**Replies:** 0\
**Last updated:** [June 29, 2024, 11:18pm UTC](https://discourse.vtk.org/t/wglmakecurrent-failed-in-makecurrent-happens-every-time-the-window-is-called-to-render/14143 "2024-06-29T23:18:05Z")

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import vtk from PyQt5 import QtWidgets from PyQt5.QtWidgets import QApplication, QMainWindow, QWidget, QVBoxLayout, QPushButton from PyQt5.QtCore import pyqtSignal, QObject from vtk.qt.QVTKRenderWindowInteractor impo…

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## [Different points after conversion from SITK image to VTK Image](https://discourse.vtk.org/t/different-points-after-conversion-from-sitk-image-to-vtk-image/14122)

<div class="topic-metadata">

**Author:** [@bkusuma](https://discourse.vtk.org/u/bkusuma)\
**Replies:** 3\
**Last updated:** [June 28, 2024, 1:42pm UTC](https://discourse.vtk.org/t/different-points-after-conversion-from-sitk-image-to-vtk-image/14122 "2024-06-28T13:42:55Z")

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I am trying to convert a SITK Image with its corresponding spacing, origin, and direction metadata into a VTK Image, with a conversion to a numpy array in between. However, when I try to grab a point within the VTK Imag…

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