# Latest

**URL:** https://discourse.vtk.org/latest.md?page=97

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

**Page:** 98

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## [How Can Rotate vtkimageData?](https://discourse.vtk.org/t/how-can-rotate-vtkimagedata/10760)

<div class="topic-metadata">

**Author:** [@m.h.shanazary](https://discourse.vtk.org/u/m.h.shanazary)\
**Replies:** 1\
**Last updated:** [February 22, 2023, 2:46pm UTC](https://discourse.vtk.org/t/how-can-rotate-vtkimagedata/10760 "2023-02-22T14:46:44Z")

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Hi I Try To Rotate Image Data In First Try I rotate Image Actor In Image Viewer2 But in try to get position Of Pixel with cell picker failed position so Wrong And Value Of Pixel its wrong. I try to rotate image data wi…

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## [Nifti header and image resolutions](https://discourse.vtk.org/t/nifti-header-and-image-resolutions/10713)

<div class="topic-metadata">

**Author:** [@totte\_karlsson](https://discourse.vtk.org/u/totte_karlsson)\
**Replies:** 1\
**Last updated:** [February 21, 2023, 8:23pm UTC](https://discourse.vtk.org/t/nifti-header-and-image-resolutions/10713 "2023-02-21T20:23:05Z")

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Hello, This may be a question more specific to the Nifti format than VTK. However, I’m using vtk’s Nifti reader that works great. We have several volumes of brain image data that are acquired at various resolutions. Fo…

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## [ICP Translation Error](https://discourse.vtk.org/t/icp-translation-error/10703)

<div class="topic-metadata">

**Author:** [@dauso](https://discourse.vtk.org/u/dauso)\
**Replies:** 5\
**Last updated:** [February 21, 2023, 2:13pm UTC](https://discourse.vtk.org/t/icp-translation-error/10703 "2023-02-21T14:13:22Z")

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I am trying to use ICP in VTK. I have created a simple box shape of size 30x40x20. The fixed (target) box is axis aligned, and the moving (source) box is rotated by 30 degrees along the X-axis. ICP result and rotation c…

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## [Augmenting vtkPolyData with multiple different tuples of point/cell data](https://discourse.vtk.org/t/augmenting-vtkpolydata-with-multiple-different-tuples-of-point-cell-data/10732)

<div class="topic-metadata">

**Author:** [@sboogert](https://discourse.vtk.org/u/sboogert)\
**Replies:** 2\
**Last updated:** [February 21, 2023, 8:49am UTC](https://discourse.vtk.org/t/augmenting-vtkpolydata-with-multiple-different-tuples-of-point-cell-data/10732 "2023-02-21T08:49:29Z")

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I have a problem that reuses a significant amount of geometry in the form of vtkPolyData. I would like like to be able to modify the vtkPolydata with different vtkDoubleArrays for the point/cell data. So is there a filt…

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## [3D Lasso on a volume](https://discourse.vtk.org/t/3d-lasso-on-a-volume/10733)

<div class="topic-metadata">

**Author:** [@AndreAhmed](https://discourse.vtk.org/u/AndreAhmed)\
**Replies:** 3\
**Last updated:** [February 21, 2023, 7:26am UTC](https://discourse.vtk.org/t/3d-lasso-on-a-volume/10733 "2023-02-21T07:26:01Z")

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Hello, I’m looking for an algorithm or an example for a 3D Lasso on 3D Volume. I was looking for VtkVolumePicker class, but in the example there is no volume that is input into that class, all I see is picker.Pick(x,y,…

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## [vtkMetaImageReader: getting additional (arbitrary) meta tags?](https://discourse.vtk.org/t/vtkmetaimagereader-getting-additional-arbitrary-meta-tags/10728)

<div class="topic-metadata">

**Author:** [@Ingmar](https://discourse.vtk.org/u/Ingmar)\
**Replies:** 4\
**Last updated:** [February 20, 2023, 9:13pm UTC](https://discourse.vtk.org/t/vtkmetaimagereader-getting-additional-arbitrary-meta-tags/10728 "2023-02-20T21:13:20Z")

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MetaIO image files may contain various tags (such as https://itk.org/Wiki/ITK/MetaIO/Documentation#Associated\_transformations and https://itk.org/Wiki/ITK/MetaIO/Documentation#Reference:\_Tags\_of\_MetaImage) such as Cente…

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## [How to apply a colour map to a texture?](https://discourse.vtk.org/t/how-to-apply-a-colour-map-to-a-texture/10692)

<div class="topic-metadata">

**Author:** [@joaomlap](https://discourse.vtk.org/u/joaomlap)\
**Replies:** 8\
**Last updated:** [February 20, 2023, 7:36pm UTC](https://discourse.vtk.org/t/how-to-apply-a-colour-map-to-a-texture/10692 "2023-02-20T19:36:44Z")

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Hi I am using a png image as such: const image0 = new Image(); image0.src = pngImage0; const planeSource = vtkPlaneSource.newInstance(); const mapper = vtkMapper.newInstance(); const actor = vtkActor.newInstance(); act…

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## [Marching cube behavior changed](https://discourse.vtk.org/t/marching-cube-behavior-changed/10712)

<div class="topic-metadata">

**Author:** [@lucas\_rouhier](https://discourse.vtk.org/u/lucas_rouhier)\
**Replies:** 12\
**Last updated:** [February 20, 2023, 1:28pm UTC](https://discourse.vtk.org/t/marching-cube-behavior-changed/10712 "2023-02-20T13:28:30Z")

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Hello, Since updating to vtk 9 from vtk8.1.1 I have noticed a slight difference in the marching cube operation. The Spacing used is not rounded as it was before. so the conversion from float (here 0.15) return 0.150000…

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## [How to remove an event from an interactor](https://discourse.vtk.org/t/how-to-remove-an-event-from-an-interactor/10720)

<div class="topic-metadata">

**Author:** [@dexter](https://discourse.vtk.org/u/dexter)\
**Replies:** 4\
**Last updated:** [February 20, 2023, 10:10am UTC](https://discourse.vtk.org/t/how-to-remove-an-event-from-an-interactor/10720 "2023-02-20T10:10:20Z")

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Hi, After adding an onLeftButtonPress in an GenericRenderWindow interactor, I want to remove this event listener, I didn’t find a way to do so, I tried the unbindEvents() but it removes all Events from the interactor

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## [How to read a custom formatted PLY file?](https://discourse.vtk.org/t/how-to-read-a-custom-formatted-ply-file/10718)

<div class="topic-metadata">

**Author:** [@saturdays13](https://discourse.vtk.org/u/saturdays13)\
**Replies:** 5\
**Last updated:** [February 20, 2023, 7:47am UTC](https://discourse.vtk.org/t/how-to-read-a-custom-formatted-ply-file/10718 "2023-02-20T07:47:36Z")

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I would like to know if VTK can load a PLY file of the following format. File header) ply format binary\_little\_endian 1.0 comment Zivid Point Cloud element vertex 2304000 property float x property float y proper…

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## [How to Pick Edge?](https://discourse.vtk.org/t/how-to-pick-edge/10719)

<div class="topic-metadata">

**Author:** [@sunlin0oo](https://discourse.vtk.org/u/sunlin0oo)\
**Replies:** 9\
**Last updated:** [February 20, 2023, 3:18am UTC](https://discourse.vtk.org/t/how-to-pick-edge/10719 "2023-02-20T03:18:56Z")

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Hi！my current Polydata contains Line but not Ploy. I want to pick up the relevant information of such a red line. How should I do it? (ps:I presuppose that I have the polyline selected and go to render) Now,My curre…

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## [Example of fetching data to a vtkDataArray](https://discourse.vtk.org/t/example-of-fetching-data-to-a-vtkdataarray/10694)

<div class="topic-metadata">

**Author:** [@Pierre-yves\_Meyer](https://discourse.vtk.org/u/Pierre-yves_Meyer)\
**Replies:** 2\
**Last updated:** [February 19, 2023, 9:27pm UTC](https://discourse.vtk.org/t/example-of-fetching-data-to-a-vtkdataarray/10694 "2023-02-19T21:27:52Z")

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Hello, is there an example to use the “Scalar array reference” explained here https://kitware.github.io/vtk-js/docs/structures\_DataArray.html I couldn’t figure how you can use ref data to ask an url for an array for ex…

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## [VTK file created using Python API is showing missing elements](https://discourse.vtk.org/t/vtk-file-created-using-python-api-is-showing-missing-elements/10723)

<div class="topic-metadata">

**Author:** [@Renard](https://discourse.vtk.org/u/Renard)\
**Replies:** 5\
**Last updated:** [February 19, 2023, 7:37pm UTC](https://discourse.vtk.org/t/vtk-file-created-using-python-api-is-showing-missing-elements/10723 "2023-02-19T19:37:01Z")

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Hi, I’m using the Python API of VTK to convert some Vector data to VTP files. My vector data is in the following format. (1) A coord.out file, which contains the cell number and the cartesian coordinates of each cell …

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## [Clipping problem with VTK 8.2, MINGW 64Bit and QT 5.14.2](https://discourse.vtk.org/t/clipping-problem-with-vtk-8-2-mingw-64bit-and-qt-5-14-2/10681)

<div class="topic-metadata">

**Author:** [@Newkid](https://discourse.vtk.org/u/Newkid)\
**Replies:** 1\
**Last updated:** [February 19, 2023, 2:39pm UTC](https://discourse.vtk.org/t/clipping-problem-with-vtk-8-2-mingw-64bit-and-qt-5-14-2/10681 "2023-02-19T14:39:44Z")

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I’ve been trying to clip a multi-actors mesh with clipPolyData, the expected outcome looks like as following in ParaView. Anyway, I follow the VTK example named “CapClip” to create the clipping function , it seems th…

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## [How can I load streamline (.vtk or .trk),and show it?](https://discourse.vtk.org/t/how-can-i-load-streamline-vtk-or-trk-and-show-it/10629)

<div class="topic-metadata">

**Author:** [@Ewing](https://discourse.vtk.org/u/Ewing)\
**Replies:** 11\
**Last updated:** [February 18, 2023, 4:08pm UTC](https://discourse.vtk.org/t/how-can-i-load-streamline-vtk-or-trk-and-show-it/10629 "2023-02-18T16:08:23Z")

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I search so many case in examples,but no answer. I want load a streamline fie(.vtk or .trk),and show it by vtkjs,like in 3dslicer Help me,thanks a lot trk file vtk file

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## [Slicer-like dicom import](https://discourse.vtk.org/t/slicer-like-dicom-import/10724)

<div class="topic-metadata">

**Author:** [@wzaylor](https://discourse.vtk.org/u/wzaylor)\
**Replies:** 0\
**Last updated:** [February 17, 2023, 10:17pm UTC](https://discourse.vtk.org/t/slicer-like-dicom-import/10724 "2023-02-17T22:17:13Z")

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Hi, I’m looking to load multiple dicom series and view the images using VTK. I setup ITK to load the images, then converted to vtkImageData, however, the images are not aligned appropriately. Specifically, the scout vi…

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## [How to turn off interpolation for discrete label segmentation image?](https://discourse.vtk.org/t/how-to-turn-off-interpolation-for-discrete-label-segmentation-image/10706)

<div class="topic-metadata">

**Author:** [@jilei-hao](https://discourse.vtk.org/u/jilei-hao)\
**Replies:** 4\
**Last updated:** [February 17, 2023, 1:56am UTC](https://discourse.vtk.org/t/how-to-turn-off-interpolation-for-discrete-label-segmentation-image/10706 "2023-02-17T01:56:06Z")

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I’m rendering a segmentation overlay with discrete labels 1, 2, 4 and background 0 in the image. And looks like I have to pick interpolation type between Linear and Nearest. Either interpolation type renders the data inc…

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## [Embree in progress](https://discourse.vtk.org/t/embree-in-progress/10715)

<div class="topic-metadata">

**Author:** [@Jens\_Munk\_Hansen](https://discourse.vtk.org/u/Jens_Munk_Hansen)\
**Replies:** 1\
**Last updated:** [February 16, 2023, 10:59pm UTC](https://discourse.vtk.org/t/embree-in-progress/10715 "2023-02-16T22:59:11Z")

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Hi Guys I am working on making CPU raycasting within VTK using Embree, The code below works great now. What would be the best way to “steal” vertexBuffers and indexBuffers. I am thinking the capability to do real-time …

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## [Scaling a Nifti Volume](https://discourse.vtk.org/t/scaling-a-nifti-volume/10658)

<div class="topic-metadata">

**Author:** [@totte\_karlsson](https://discourse.vtk.org/u/totte_karlsson)\
**Replies:** 5\
**Last updated:** [February 14, 2023, 9:21pm UTC](https://discourse.vtk.org/t/scaling-a-nifti-volume/10658 "2023-02-14T21:21:16Z")

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Hello, When reading a volume as a TIFF stack using the vtkTiffReader the size of the volume can be scaled using the readers SetDataSpacing function. However, when reading a Nifti volume, using the Nifti reader, the Set…

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## [convert .nii to a mesh](https://discourse.vtk.org/t/convert-nii-to-a-mesh/10677)

<div class="topic-metadata">

**Author:** [@Hamid\_Fsian](https://discourse.vtk.org/u/Hamid_Fsian)\
**Replies:** 6\
**Last updated:** [February 16, 2023, 7:46pm UTC](https://discourse.vtk.org/t/convert-nii-to-a-mesh/10677 "2023-02-16T19:46:06Z")

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Dear Community, I am trying to convert a niftii file into a mesh ( and later save it as .obj) and I want to color this latter using the pixel intesity from the nifti volume. Is it possible using vtk and python ?

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## [Why I'm having this warning, Too many active WebGL contexts. Oldest context will be lost.](https://discourse.vtk.org/t/why-im-having-this-warning-too-many-active-webgl-contexts-oldest-context-will-be-lost/10670)

<div class="topic-metadata">

**Author:** [@dexter](https://discourse.vtk.org/u/dexter)\
**Replies:** 8\
**Last updated:** [February 16, 2023, 3:53pm UTC](https://discourse.vtk.org/t/why-im-having-this-warning-too-many-active-webgl-contexts-oldest-context-will-be-lost/10670 "2023-02-16T15:53:59Z")

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In my application, I have ResliceCursourWidget (3 genericRenderWindows) + a genericRenderWindow to display 3 3D actors, In this application the users may have many interactions with those renderWindows, (change the Res…

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## [Dynamic usage of VTK - generating binary not linked to VTK](https://discourse.vtk.org/t/dynamic-usage-of-vtk-generating-binary-not-linked-to-vtk/10675)

<div class="topic-metadata">

**Author:** [@NomisTuo](https://discourse.vtk.org/u/NomisTuo)\
**Replies:** 5\
**Last updated:** [February 16, 2023, 9:05am UTC](https://discourse.vtk.org/t/dynamic-usage-of-vtk-generating-binary-not-linked-to-vtk/10675 "2023-02-16T09:05:11Z")

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Dear all, I built VTK-9.2.2 as I would like to use it dynamically within a tool if the user wants to get some graphical views. To achieve this, a c++ library within which various “vtk” methods are exposed using “DLLEXP…

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## [Building VTK-9 with Emscripten+GLES for rendering](https://discourse.vtk.org/t/building-vtk-9-with-emscripten-gles-for-rendering/3038)

<div class="topic-metadata">

**Author:** [@Sebastien\_Jourdain](https://discourse.vtk.org/u/Sebastien_Jourdain)\
**Replies:** 10\
**Last updated:** [February 16, 2023, 6:27am UTC](https://discourse.vtk.org/t/building-vtk-9-with-emscripten-gles-for-rendering/3038 "2023-02-16T06:27:53Z")

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I’m trying to port the excellent work that was done here on an old version of VTK to todays VTK while hoping it could make it to VTK 9. Steps to reproduce Getting the sources Create and go into a working directory for t…

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## [Memory leak occurs if I use vtkSmartPointer in sub-thread.](https://discourse.vtk.org/t/memory-leak-occurs-if-i-use-vtksmartpointer-in-sub-thread/10631)

<div class="topic-metadata">

**Author:** [@sohnishi](https://discourse.vtk.org/u/sohnishi)\
**Replies:** 5\
**Last updated:** [February 16, 2023, 4:57am UTC](https://discourse.vtk.org/t/memory-leak-occurs-if-i-use-vtksmartpointer-in-sub-thread/10631 "2023-02-16T04:57:11Z")

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I’m trying to create vtkPolyData from implicit functions. But this code makes memory leak if I use std::thread. Does anyone know the workarounds? I’m using Linux debian11 and vtk 9.0.1 on x86\_64 PC. #include \<iostrea…

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## [vtk rendering speed issue with large amount of actors (\>1000)](https://discourse.vtk.org/t/vtk-rendering-speed-issue-with-large-amount-of-actors-1000/10696)

<div class="topic-metadata">

**Author:** [@jackshen2028](https://discourse.vtk.org/u/jackshen2028)\
**Replies:** 1\
**Last updated:** [February 16, 2023, 1:20am UTC](https://discourse.vtk.org/t/vtk-rendering-speed-issue-with-large-amount-of-actors-1000/10696 "2023-02-16T01:20:09Z")

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Dear Community, I want to read a simulation data and do postprocessing with vtk. Different kinds of mesh (cell in vtk) are orginized into components, and I want to be able to treat them individually in terms of altering…

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## [VTK extrusion normal has self intersection cells](https://discourse.vtk.org/t/vtk-extrusion-normal-has-self-intersection-cells/10583)

<div class="topic-metadata">

**Author:** [@Hanxin\_Hua](https://discourse.vtk.org/u/Hanxin_Hua)\
**Replies:** 15\
**Last updated:** [February 16, 2023, 12:01am UTC](https://discourse.vtk.org/t/vtk-extrusion-normal-has-self-intersection-cells/10583 "2023-02-16T00:01:31Z")

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Hi, I have a very irregular surface and then called the extrusion with the normal direction. And then I found that it has all the self intersection cells. I can’t just remove them because the whole polydata will be remov…

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## [QQuickVTKInteractorAdapter.cxx:110:59: error: no matching function for call to ‘QWheelEvent](https://discourse.vtk.org/t/qquickvtkinteractoradapter-cxx59-error-no-matching-function-for-call-to-qwheelevent/7942)

<div class="topic-metadata">

**Author:** [@BlueKnight7](https://discourse.vtk.org/u/BlueKnight7)\
**Replies:** 8\
**Last updated:** [February 15, 2023, 7:23pm UTC](https://discourse.vtk.org/t/qquickvtkinteractoradapter-cxx59-error-no-matching-function-for-call-to-qwheelevent/7942 "2023-02-15T19:23:33Z")

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Am trying to build the latest, stable download (9.1.0) on Redhat Linux. Encounter the following build error: Vtk/VTK-9.1.0/GUISupport/QtQuick/QQuickVTKInteractorAdapter.cxx: In member function ‘void QQuickVTKInteractorA…

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## [Having problem about change the volume position](https://discourse.vtk.org/t/having-problem-about-change-the-volume-position/10698)

<div class="topic-metadata">

**Author:** [@MushengWu](https://discourse.vtk.org/u/MushengWu)\
**Replies:** 0\
**Last updated:** [February 15, 2023, 2:33pm UTC](https://discourse.vtk.org/t/having-problem-about-change-the-volume-position/10698 "2023-02-15T14:33:50Z")

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Sorry this problem may seem awkward. I rendered two object，and i need to move object\_B to a specific position in object\_A. And i had calculate the position and direction, here is the problem: when i set the object\_B …

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## [How long does it take to build vtk for linux in windows?](https://discourse.vtk.org/t/how-long-does-it-take-to-build-vtk-for-linux-in-windows/10640)

<div class="topic-metadata">

**Author:** [@Sagues](https://discourse.vtk.org/u/Sagues)\
**Replies:** 7\
**Last updated:** [February 15, 2023, 2:28pm UTC](https://discourse.vtk.org/t/how-long-does-it-take-to-build-vtk-for-linux-in-windows/10640 "2023-02-15T14:28:06Z")

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I am building vtk library for linux in windows (WSL). I have done the steps in the following page: https://gitlab.kitware.com/vtk/vtk/-/blob/master/Documentation/dev/getting\_started\_linux.md However I did not use para…

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## [Have problem on render my data](https://discourse.vtk.org/t/have-problem-on-render-my-data/10674)

<div class="topic-metadata">

**Author:** [@MushengWu](https://discourse.vtk.org/u/MushengWu)\
**Replies:** 5\
**Last updated:** [February 15, 2023, 1:56pm UTC](https://discourse.vtk.org/t/have-problem-on-render-my-data/10674 "2023-02-15T13:56:15Z")

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I am new for VTK, and recently my project need it,and i have many question waiting for resolution Here is one: when I load my data, i used the following code: def load\_Nifti(data): Nifti = vtkNIFTIImageReader() Nif…

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