# Support

**URL:** https://discourse.vtk.org/c/support/6.md?page=86

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

**Page:** 87

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## [Legacy PolyData File Compatibility](https://discourse.vtk.org/t/legacy-polydata-file-compatibility/5354)

<div class="topic-metadata">

**Author:** [@tbirdso](https://discourse.vtk.org/u/tbirdso)\
**Replies:** 10\
**Last updated:** [December 30, 2021, 2:44am UTC](https://discourse.vtk.org/t/legacy-polydata-file-compatibility/5354 "2021-12-30T02:44:17Z")

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Hi there! I’m trying to use VTK’s Python wrapping to resample an ITK mesh stored in a legacy .vtk file with VTK Data Format 2.0. It appears that vtkPolyDataReader is able to successfully import from this format, but wri…

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## [Is there an easy vtkTexture shallow copy from vtkOBJImporter to a vtkClipClosedSurface or a vtkFrustumSource](https://discourse.vtk.org/t/is-there-an-easy-vtktexture-shallow-copy-from-vtkobjimporter-to-a-vtkclipclosedsurface-or-a-vtkfrustumsource/7518)

<div class="topic-metadata">

**Author:** [@Joel\_Mckay](https://discourse.vtk.org/u/Joel_Mckay)\
**Replies:** 0\
**Last updated:** [December 29, 2021, 3:45am UTC](https://discourse.vtk.org/t/is-there-an-easy-vtktexture-shallow-copy-from-vtkobjimporter-to-a-vtkclipclosedsurface-or-a-vtkfrustumsource/7518 "2021-12-29T03:45:19Z")

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This old site has described an import/export method, but I suspect there must be an easier generic way of handling this common task in libvtk. As the initial texture/map is not being modified, it makes sense someone li…

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## [QVTKOpenGLNativeWidget turn to be transparent when pick actor](https://discourse.vtk.org/t/qvtkopenglnativewidget-turn-to-be-transparent-when-pick-actor/7445)

<div class="topic-metadata">

**Author:** [@zhang-qiang-github](https://discourse.vtk.org/u/zhang-qiang-github)\
**Replies:** 1\
**Last updated:** [December 29, 2021, 1:24am UTC](https://discourse.vtk.org/t/qvtkopenglnativewidget-turn-to-be-transparent-when-pick-actor/7445 "2021-12-29T01:24:28Z")

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I am implement the project with QVTKOpenGLNativeWidget, and it works fine. Then, I want to pick actor in the mouseMoveEvent, but the widget turn to be transparent when the cursor is move to the button (no click): …

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## [Recording or taking screenshots of Tait-Bryan Rotation on Object in VTK](https://discourse.vtk.org/t/recording-or-taking-screenshots-of-tait-bryan-rotation-on-object-in-vtk/7493)

<div class="topic-metadata">

**Author:** [@Charles\_Shin](https://discourse.vtk.org/u/Charles_Shin)\
**Replies:** 2\
**Last updated:** [December 28, 2021, 7:54pm UTC](https://discourse.vtk.org/t/recording-or-taking-screenshots-of-tait-bryan-rotation-on-object-in-vtk/7493 "2021-12-28T19:54:36Z")

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Hi, I am trying to record or take screenshot of rotating multiple objects (head, tumor, etc.) in tait-bryan/euler fashion with specific angles. However, I can only find camera rotation for VTK, which is not what I wanted…

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## [How to show an local axes in the center of actor?](https://discourse.vtk.org/t/how-to-show-an-local-axes-in-the-center-of-actor/7514)

<div class="topic-metadata">

**Author:** [@AlexLuya](https://discourse.vtk.org/u/AlexLuya)\
**Replies:** 1\
**Last updated:** [December 28, 2021, 1:38pm UTC](https://discourse.vtk.org/t/how-to-show-an-local-axes-in-the-center-of-actor/7514 "2021-12-28T13:38:53Z")

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Something like this: As you can see,the left cube has a local axes in the center when clicking it,how to do same thing with VTK?

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## [How to prevent the ball to be streched to an ellipsoid when dragging the window.](https://discourse.vtk.org/t/how-to-prevent-the-ball-to-be-streched-to-an-ellipsoid-when-dragging-the-window/7515)

<div class="topic-metadata">

**Author:** [@AlexLuya](https://discourse.vtk.org/u/AlexLuya)\
**Replies:** 1\
**Last updated:** [December 28, 2021, 1:18pm UTC](https://discourse.vtk.org/t/how-to-prevent-the-ball-to-be-streched-to-an-ellipsoid-when-dragging-the-window/7515 "2021-12-28T13:18:41Z")

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As you can,when dragging the bottom edge of window,the ball becomes an ellipsoid After clicking the windows,it is restored as ball. How to fix this issue?

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## [vtkMarchingSquares for DICOM \*.dcm/png/bmp stack](https://discourse.vtk.org/t/vtkmarchingsquares-for-dicom-dcm-png-bmp-stack/7510)

<div class="topic-metadata">

**Author:** [@cfd\_payne](https://discourse.vtk.org/u/cfd_payne)\
**Replies:** 2\
**Last updated:** [December 28, 2021, 11:24am UTC](https://discourse.vtk.org/t/vtkmarchingsquares-for-dicom-dcm-png-bmp-stack/7510 "2021-12-28T11:24:08Z")

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@lassoan @dgobbi Continuing the discussion from Stack of PNG files to be rendered as 3D: I have a similar situation where the data seems 2D+t \[typically coronary angiograms\], i’m trying to understand “qualitative” flow…

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## [vtkExecutableRunner : ported to Windows ?](https://discourse.vtk.org/t/vtkexecutablerunner-ported-to-windows/7501)

<div class="topic-metadata">

**Author:** [@Nicholas\_Yue](https://discourse.vtk.org/u/Nicholas_Yue)\
**Replies:** 2\
**Last updated:** [December 27, 2021, 1:57pm UTC](https://discourse.vtk.org/t/vtkexecutablerunner-ported-to-windows/7501 "2021-12-27T13:57:45Z")

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I am able to run the command “echo HELLO WORLD” via vtkExecutableRunner on Linux but not on Windows. I get the following errors. Any suggestion as to how I might be able to fix it ? 2021-12-26 14:54:06.152 ( 0.012s) \[…

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## [how to use the vtk in VS2019](https://discourse.vtk.org/t/how-to-use-the-vtk-in-vs2019/7508)

<div class="topic-metadata">

**Author:** [@BKL](https://discourse.vtk.org/u/BKL)\
**Replies:** 0\
**Last updated:** [December 27, 2021, 1:29pm UTC](https://discourse.vtk.org/t/how-to-use-the-vtk-in-vs2019/7508 "2021-12-27T13:29:59Z")

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I am new to vtk. i have already installed vtk, but when i run the cxxexample i downloaded from the vtk website by Visual studio 2019, it says ALL\_BUILD access denied. How can I solve it?

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## [VTK-7.1.1 installation](https://discourse.vtk.org/t/vtk-7-1-1-installation/1057)

<div class="topic-metadata">

**Author:** [@sourav0921](https://discourse.vtk.org/u/sourav0921)\
**Replies:** 4\
**Last updated:** [December 27, 2021, 11:15am UTC](https://discourse.vtk.org/t/vtk-7-1-1-installation/1057 "2021-12-27T11:15:45Z")

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Hi, I was trying to install VTK-7.1.1 using cmake 3.14 in a CRAY-LINUX server. After configuration when I was trying to make it during the process it saying that, " 23%\] Building C object Utilities/KWIML/vtkkwiml/test/…

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## [Any example or tips to render sea surface(shader+FFT)?](https://discourse.vtk.org/t/any-example-or-tips-to-render-sea-surface-shader-fft/7432)

<div class="topic-metadata">

**Author:** [@AlexLuya](https://discourse.vtk.org/u/AlexLuya)\
**Replies:** 5\
**Last updated:** [December 27, 2021, 9:30am UTC](https://discourse.vtk.org/t/any-example-or-tips-to-render-sea-surface-shader-fft/7432 "2021-12-27T09:30:18Z")

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Any example or tips to do it? If can’t be done with VTK,any opengl integration mechanism suggestion is appreciated also.

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## [Any suggestions for beginners :) on improving color mappings](https://discourse.vtk.org/t/any-suggestions-for-beginners-on-improving-color-mappings/7495)

<div class="topic-metadata">

**Author:** [@Kostas\_Politis](https://discourse.vtk.org/u/Kostas_Politis)\
**Replies:** 1\
**Last updated:** [December 26, 2021, 10:33pm UTC](https://discourse.vtk.org/t/any-suggestions-for-beginners-on-improving-color-mappings/7495 "2021-12-26T22:33:34Z")

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Hello all, I’ve just started using VTK so I’m trying some mapper options for biquadratic quads in a relatively coarse mesh(1600 cells). Without and with interpolation (option aVtkMapper-\>InterpolateScalarsBeforeMappingO…

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## [How to listen zoom event to to keep a fixed ratio of axises\_length/window\_width?](https://discourse.vtk.org/t/how-to-listen-zoom-event-to-to-keep-a-fixed-ratio-of-axises-length-window-width/7486)

<div class="topic-metadata">

**Author:** [@AlexLuya](https://discourse.vtk.org/u/AlexLuya)\
**Replies:** 1\
**Last updated:** [December 26, 2021, 2:48pm UTC](https://discourse.vtk.org/t/how-to-listen-zoom-event-to-to-keep-a-fixed-ratio-of-axises-length-window-width/7486 "2021-12-26T14:48:35Z")

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Hello, I have put an vtkAxesActor in the centor of window,if putting a big object or zoom out too much,this actor will become tiny.Any way to keep a fixed ratio of axis\_length/window\_width?I want to listen to zoom even…

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## [Error: no override found for 'vtkGPUVolumeRayCastMapper'](https://discourse.vtk.org/t/error-no-override-found-for-vtkgpuvolumeraycastmapper/7483)

<div class="topic-metadata">

**Author:** [@jjjkk](https://discourse.vtk.org/u/jjjkk)\
**Replies:** 1\
**Last updated:** [December 26, 2021, 2:31pm UTC](https://discourse.vtk.org/t/error-no-override-found-for-vtkgpuvolumeraycastmapper/7483 "2021-12-26T14:31:47Z")

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I use VTK for a lot. Most of class work well but now I got this error report after I want to use volume renderer. Generic Warning: In C:\\vcpkg\\buildtrees\\vtk\\src\\edd2e5233f-f32830fbf2.clean\\Rendering\\Volume\\vtkGPUVolume…

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## [VTK's Qt Widget registration with Qt Designer/Creator ?](https://discourse.vtk.org/t/vtks-qt-widget-registration-with-qt-designer-creator/7498)

<div class="topic-metadata">

**Author:** [@Nicholas\_Yue](https://discourse.vtk.org/u/Nicholas_Yue)\
**Replies:** 0\
**Last updated:** [December 24, 2021, 7:33pm UTC](https://discourse.vtk.org/t/vtks-qt-widget-registration-with-qt-designer-creator/7498 "2021-12-24T19:33:15Z")

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I have build VTK 9.1.0 from source on Ubuntu 18.0.4 with Qt 5.14.2 I understand there were some changes to naming of Qt related widget in VTK Googling mentioned something called QVTKWidget which is a plugin Qt Creator/…

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## [Use of Update() in vtk7](https://discourse.vtk.org/t/use-of-update-in-vtk7/7491)

<div class="topic-metadata">

**Author:** [@IT-five](https://discourse.vtk.org/u/IT-five)\
**Replies:** 1\
**Last updated:** [December 24, 2021, 1:32pm UTC](https://discourse.vtk.org/t/use-of-update-in-vtk7/7491 "2021-12-24T13:32:43Z")

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read file for geometry reader = vtk.vtkXMLMultiBlockDataReader() reader.SetFileName(geometry\_file) reader.Update() data = reader.GetOutput() data\_iterator = data.NewIterator() img\_data = data\_iterator.GetCurr…

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## [Code from the pipeline of MDI appllication which worked with 5.8. Need help upgrading it to 9.1](https://discourse.vtk.org/t/code-from-the-pipeline-of-mdi-appllication-which-worked-with-5-8-need-help-upgrading-it-to-9-1/7487)

<div class="topic-metadata">

**Author:** [@Taimour](https://discourse.vtk.org/u/Taimour)\
**Replies:** 4\
**Last updated:** [December 24, 2021, 6:59am UTC](https://discourse.vtk.org/t/code-from-the-pipeline-of-mdi-appllication-which-worked-with-5-8-need-help-upgrading-it-to-9-1/7487 "2021-12-24T06:59:36Z")

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Hi Everyone, I am working on a project which includes following code. This code was developed in vtk5.8 and now I am trying to make it work in vtk9.1. The code is compiling but it is not rendering anything. Can Anyone l…

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## [Vtk Pipeline Query](https://discourse.vtk.org/t/vtk-pipeline-query/7463)

<div class="topic-metadata">

**Author:** [@Taimour](https://discourse.vtk.org/u/Taimour)\
**Replies:** 1\
**Last updated:** [December 23, 2021, 2:45pm UTC](https://discourse.vtk.org/t/vtk-pipeline-query/7463 "2021-12-23T14:45:37Z")

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Hi everyone, I have few queries: Is the pipeline developed in version 5.8 of VTK can work same in vtk 9.1 without any changes? Do we have to worry about the internal structure of pipeline or we can simply use input me…

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## [GMSH](https://discourse.vtk.org/t/gmsh/3593)

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**Author:** [@rdbrn](https://discourse.vtk.org/u/rdbrn)\
**Replies:** 4\
**Last updated:** [December 23, 2021, 1:25pm UTC](https://discourse.vtk.org/t/gmsh/3593 "2021-12-23T13:25:38Z")

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Is there a way to import gmsh files into vtk? I did find a gmsh reader in the paraview repo but there does not seem to be such a thing as vtkGmshReader in vtk.

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## [Are there vtkCylinderSource options for hexagon glyph tiled structuredGrid?](https://discourse.vtk.org/t/are-there-vtkcylindersource-options-for-hexagon-glyph-tiled-structuredgrid/7481)

<div class="topic-metadata">

**Author:** [@Joel\_Mckay](https://discourse.vtk.org/u/Joel_Mckay)\
**Replies:** 0\
**Last updated:** [December 23, 2021, 7:51am UTC](https://discourse.vtk.org/t/are-there-vtkcylindersource-options-for-hexagon-glyph-tiled-structuredgrid/7481 "2021-12-23T07:51:36Z")

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The issue with this example is the Rotate in the pipeline causes the whole grid to move on render. Cheers, =) J vtkSmartPointer\<vtkActor\> PointToGlyphHexagon(vtkPoints\* points, double const& scale) { auto bounds = p…

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## [vtkAlgorithm : SetInputConnection() vs AddInputConnection() ?](https://discourse.vtk.org/t/vtkalgorithm-setinputconnection-vs-addinputconnection/7475)

<div class="topic-metadata">

**Author:** [@Nicholas\_Yue](https://discourse.vtk.org/u/Nicholas_Yue)\
**Replies:** 1\
**Last updated:** [December 22, 2021, 11:54pm UTC](https://discourse.vtk.org/t/vtkalgorithm-setinputconnection-vs-addinputconnection/7475 "2021-12-22T23:54:27Z")

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I am reading the documentation about the methods here but can’t wrap my head around when to use which one If I am simply connecting the outputport of one node to the inputport of another node, do I add or set ? Cheers

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## [Dynamically changing opacity in Python with vtkPieceWiseFunction](https://discourse.vtk.org/t/dynamically-changing-opacity-in-python-with-vtkpiecewisefunction/7470)

<div class="topic-metadata">

**Author:** [@ClaraMaria](https://discourse.vtk.org/u/ClaraMaria)\
**Replies:** 0\
**Last updated:** [December 22, 2021, 3:21pm UTC](https://discourse.vtk.org/t/dynamically-changing-opacity-in-python-with-vtkpiecewisefunction/7470 "2021-12-22T15:21:35Z")

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Hi! I am trying to figure out if it is possible to modify the vtkPieceWiseFunction, since I am trying to dynamically change the opacity according to a specific formula when using RayCasting. I’m using python 3.8. The f…

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## [Wrong selection when using polydatamapper-\>SetSelection method.](https://discourse.vtk.org/t/wrong-selection-when-using-polydatamapper-setselection-method/7435)

<div class="topic-metadata">

**Author:** [@yuhaoqiu](https://discourse.vtk.org/u/yuhaoqiu)\
**Replies:** 3\
**Last updated:** [December 22, 2021, 12:17pm UTC](https://discourse.vtk.org/t/wrong-selection-when-using-polydatamapper-setselection-method/7435 "2021-12-22T12:17:00Z")

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I’m learning how to use fast pre-select with VTK. I learned that using the SetSelection method of the Mapper class can effectively use the data in the buffer for fast selection. I wrote a demo, but I met some problems. …

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## [VTK 9 Help vtkPolyData GetScalarFieldCriticalIndex](https://discourse.vtk.org/t/vtk-9-help-vtkpolydata-getscalarfieldcriticalindex/7453)

<div class="topic-metadata">

**Author:** [@AlexUtrobin](https://discourse.vtk.org/u/AlexUtrobin)\
**Replies:** 2\
**Last updated:** [December 22, 2021, 7:30am UTC](https://discourse.vtk.org/t/vtk-9-help-vtkpolydata-getscalarfieldcriticalindex/7453 "2021-12-22T07:30:14Z")

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Finding critical point in vtkPolyData. Found the GetScalarFieldCriticalIndex method, but the method always returns ERR\_INCORRECT\_FIELD (-3), what am I doing wrong? vtkDoubleArray\* da = dynamic\_cast\<vtkDoubleArray\*\>(pd-\>G…

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## [How generate a set of interest points on a surface from some points.](https://discourse.vtk.org/t/how-generate-a-set-of-interest-points-on-a-surface-from-some-points/7436)

<div class="topic-metadata">

**Author:** [@Miguel\_Socorro](https://discourse.vtk.org/u/Miguel_Socorro)\
**Replies:** 9\
**Last updated:** [December 22, 2021, 2:03am UTC](https://discourse.vtk.org/t/how-generate-a-set-of-interest-points-on-a-surface-from-some-points/7436 "2021-12-22T02:03:24Z")

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Hello, I have been able to see in some surgical navigation systems (like Mako for example) selecting some points, the system can generate automatically a broader set of points in places of interest. For example, in this…

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## [Deprecating \`vtkDataArray::LookupTable\`?](https://discourse.vtk.org/t/deprecating-vtkdataarray-lookuptable/7457)

<div class="topic-metadata">

**Author:** [@Yohann\_Bearzi](https://discourse.vtk.org/u/Yohann_Bearzi)\
**Replies:** 0\
**Last updated:** [December 21, 2021, 8:22pm UTC](https://discourse.vtk.org/t/deprecating-vtkdataarray-lookuptable/7457 "2021-12-21T20:22:03Z")

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It seems like vtkDataArray::LookupTable has no use anymore in VTK. Is anyone still using this API, or is it ripe for deprecation? Lookup tables are now dealt with at the mapper level. If you still use this API, please s…

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## [How to read TimeValues or write TimeStep](https://discourse.vtk.org/t/how-to-read-timevalues-or-write-timestep/7439)

<div class="topic-metadata">

**Author:** [@olafx](https://discourse.vtk.org/u/olafx)\
**Replies:** 0\
**Last updated:** [December 21, 2021, 6:18am UTC](https://discourse.vtk.org/t/how-to-read-timevalues-or-write-timestep/7439 "2021-12-21T06:18:31Z")

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I’m writing time dependent files using the WriteTimeStep(time) function. This makes a TimeValues array in the XML file of whatever times I give. The problem I’m having is that I can’t seem to access TimeValues with the r…

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## [vtk class for wrapping/handling external command line program](https://discourse.vtk.org/t/vtk-class-for-wrapping-handling-external-command-line-program/7403)

<div class="topic-metadata">

**Author:** [@Nicholas\_Yue](https://discourse.vtk.org/u/Nicholas_Yue)\
**Replies:** 6\
**Last updated:** [December 17, 2021, 8:16am UTC](https://discourse.vtk.org/t/vtk-class-for-wrapping-handling-external-command-line-program/7403 "2021-12-17T08:16:27Z")

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I am looking to wrap some external commands in a C++ vtk class for developer’s convenience. What class should I look into ? Some of the external program are generator of information (source), some are filters and some …

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## [CT reconstruction with variable z spacing (slow interpolation from vtkRectilinearGrid to vtkImageData)](https://discourse.vtk.org/t/ct-reconstruction-with-variable-z-spacing-slow-interpolation-from-vtkrectilineargrid-to-vtkimagedata/7406)

<div class="topic-metadata">

**Author:** [@simonesneault](https://discourse.vtk.org/u/simonesneault)\
**Replies:** 9\
**Last updated:** [December 18, 2021, 3:31pm UTC](https://discourse.vtk.org/t/ct-reconstruction-with-variable-z-spacing-slow-interpolation-from-vtkrectilineargrid-to-vtkimagedata/7406 "2021-12-18T15:31:05Z")

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Hello community ! We are trying to handle CT reconstruction with variable z spacing. In order to work with our software, we must obtain a vtkImageData with fixed spacing in all direction. What we are doing for now is t…

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## [Error building VTK with Python wrappers on Windows](https://discourse.vtk.org/t/error-building-vtk-with-python-wrappers-on-windows/7333)

<div class="topic-metadata">

**Author:** [@toddy](https://discourse.vtk.org/u/toddy)\
**Replies:** 8\
**Last updated:** [December 10, 2021, 10:37pm UTC](https://discourse.vtk.org/t/error-building-vtk-with-python-wrappers-on-windows/7333 "2021-12-10T22:37:01Z")

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I’m trying to build VTK with VS2017 and Python wrappers in debug mode and I’m seeing some strange errors. Can someone enlighten me please?

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