# Support

**URL:** https://discourse.vtk.org/c/support/6.md?page=135

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

**Page:** 136

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## [vtkPointInterpolator kernels issues (vtk 8.2)](https://discourse.vtk.org/t/vtkpointinterpolator-kernels-issues-vtk-8-2/3020)

<div class="topic-metadata">

**Author:** [@Valedy](https://discourse.vtk.org/u/Valedy)\
**Replies:** 0\
**Last updated:** [April 10, 2020, 11:13am UTC](https://discourse.vtk.org/t/vtkpointinterpolator-kernels-issues-vtk-8-2/3020 "2020-04-10T11:13:10Z")

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Hello, Sorry in advance if my english is not perfect. I try to make my explanation clear. I’m using vtkPointInterpolator in my method. Whether I use Linear or Voronoi kernel I don’t have any problem. But when I use Gau…

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## [how to add a tag to an created actor](https://discourse.vtk.org/t/how-to-add-a-tag-to-an-created-actor/2998)

<div class="topic-metadata">

**Author:** [@xuexl](https://discourse.vtk.org/u/xuexl)\
**Replies:** 3\
**Last updated:** [April 10, 2020, 11:49am UTC](https://discourse.vtk.org/t/how-to-add-a-tag-to-an-created-actor/2998 "2020-04-10T11:49:54Z")

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using “vtkSphereSource”, I have added some spheres, and i want to delete some of them that clicked. so, how to distinguish them from others. using “vtkCellPicker”, i can get the actor that clicked, but i need a check t…

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## [vtkCellArray updates](https://discourse.vtk.org/t/vtkcellarray-updates/3007)

<div class="topic-metadata">

**Author:** [@kayarre](https://discourse.vtk.org/u/kayarre)\
**Replies:** 0\
**Last updated:** [April 9, 2020, 9:03pm UTC](https://discourse.vtk.org/t/vtkcellarray-updates/3007 "2020-04-09T21:03:08Z")

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based on changes from: Upcoming changes to vtkCellArray I have some code I am trying to update to the latest VTK, and I think I am running in an issue with this new implementation. vtkPolyData is subclassed and has t…

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## [How to create a point in vtk?](https://discourse.vtk.org/t/how-to-create-a-point-in-vtk/2992)

<div class="topic-metadata">

**Author:** [@NeuZhangQiang](https://discourse.vtk.org/u/NeuZhangQiang)\
**Replies:** 2\
**Last updated:** [April 10, 2020, 2:21am UTC](https://discourse.vtk.org/t/how-to-create-a-point-in-vtk/2992 "2020-04-10T02:21:15Z")

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VTK is too complicate… I want to find the connectivity region around a point, and I want to use vtkImageConnectivityFilter. The code should be: vtkSmartPointer\<vtkImageConnectivityFilter\> connectivityFilter = vtkSmart…

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## [Simple image appplication..](https://discourse.vtk.org/t/simple-image-appplication/3006)

<div class="topic-metadata">

**Author:** [@kalpathi](https://discourse.vtk.org/u/kalpathi)\
**Replies:** 1\
**Last updated:** [April 9, 2020, 8:25pm UTC](https://discourse.vtk.org/t/simple-image-appplication/3006 "2020-04-09T20:25:06Z")

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I have to develop a small image application - reading in a sequence of images(volume) and doing some simple interactive image processing on each of them to identify some features. The breadth of classes in VTK is vast a…

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## [Anti-aliasing issues with Python VTK and Qt](https://discourse.vtk.org/t/anti-aliasing-issues-with-python-vtk-and-qt/2520)

<div class="topic-metadata">

**Author:** [@ian.liu88](https://discourse.vtk.org/u/ian.liu88)\
**Replies:** 3\
**Last updated:** [April 9, 2020, 3:00pm UTC](https://discourse.vtk.org/t/anti-aliasing-issues-with-python-vtk-and-qt/2520 "2020-04-09T15:00:38Z")

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The following Gist contains two simple VTK examples: The qt\_ex.py example runs VTK inside a Qt window, while the vtk\_ex.py runs a pure VTK window. The problem I’m facing is that the Qt version has no anti-alias. See t…

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## [My contour from vtkContourFilter doesn't show up ... but the vtkStructuredGridOutline does ...](https://discourse.vtk.org/t/my-contour-from-vtkcontourfilter-doesnt-show-up-but-the-vtkstructuredgridoutline-does/3002)

<div class="topic-metadata">

**Author:** [@cousinitt](https://discourse.vtk.org/u/cousinitt)\
**Replies:** 0\
**Last updated:** [April 9, 2020, 2:58pm UTC](https://discourse.vtk.org/t/my-contour-from-vtkcontourfilter-doesnt-show-up-but-the-vtkstructuredgridoutline-does/3002 "2020-04-09T14:58:56Z")

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I created a vtkStructuredGrid, set locations for the points, created a vtkDoubleArray containing the distance from the point (50, 0, 0), and tried to make a contour of the points that were 50 units away. I’m sure that I’…

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## [How to set the size of resliced image in vtkImageReslice ??](https://discourse.vtk.org/t/how-to-set-the-size-of-resliced-image-in-vtkimagereslice/2990)

<div class="topic-metadata">

**Author:** [@NeuZhangQiang](https://discourse.vtk.org/u/NeuZhangQiang)\
**Replies:** 0\
**Last updated:** [April 9, 2020, 1:32am UTC](https://discourse.vtk.org/t/how-to-set-the-size-of-resliced-image-in-vtkimagereslice/2990 "2020-04-09T01:32:04Z")

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Currently, I need to reslice a 2D image from a 3D volume image. The vtkImageReslice is a good choice. My code is: vtkSmartPointer\<vtkImageReslice\> resliceOperation = vtkSmartPointer\<vtkImageReslice\>::New(); resliceOper…

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## [Updating a vtkSpline](https://discourse.vtk.org/t/updating-a-vtkspline/2986)

<div class="topic-metadata">

**Author:** [@prater27](https://discourse.vtk.org/u/prater27)\
**Replies:** 0\
**Last updated:** [April 8, 2020, 6:40pm UTC](https://discourse.vtk.org/t/updating-a-vtkspline/2986 "2020-04-08T18:40:46Z")

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Hi! Thank you in advance for your support. I have implemented a small tool capable of doing simple animations from external data. The external data are a list of lines containing every line: time, 3D position and a Q…

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## [user matrix on vtk reslice cursor widget](https://discourse.vtk.org/t/user-matrix-on-vtk-reslice-cursor-widget/2981)

<div class="topic-metadata">

**Author:** [@tom1](https://discourse.vtk.org/u/tom1)\
**Replies:** 5\
**Last updated:** [April 8, 2020, 1:39pm UTC](https://discourse.vtk.org/t/user-matrix-on-vtk-reslice-cursor-widget/2981 "2020-04-08T13:39:32Z")

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Hi, VTK experts. I am trying to setup a reslice cursor widget with a user matrix. Currently, I am trying to assign the user matrix to the reslice cursor line representation, which I set to the rsc widget. In result, t…

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## [vtkPointInterpolator doesn't work, if the scalar array of the source data does not have a name](https://discourse.vtk.org/t/vtkpointinterpolator-doesnt-work-if-the-scalar-array-of-the-source-data-does-not-have-a-name/2979)

<div class="topic-metadata">

**Author:** [@Yue\_JIN](https://discourse.vtk.org/u/Yue_JIN)\
**Replies:** 1\
**Last updated:** [April 8, 2020, 6:12am UTC](https://discourse.vtk.org/t/vtkpointinterpolator-doesnt-work-if-the-scalar-array-of-the-source-data-does-not-have-a-name/2979 "2020-04-08T06:12:53Z")

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It may be a bug? This problem is not stated in document.

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## [9.0.0.rc1 CMake policy error (using CMake 3.9.3)](https://discourse.vtk.org/t/9-0-0-rc1-cmake-policy-error-using-cmake-3-9-3/2976)

<div class="topic-metadata">

**Author:** [@biagas](https://discourse.vtk.org/u/biagas)\
**Replies:** 2\
**Last updated:** [April 7, 2020, 5:17pm UTC](https://discourse.vtk.org/t/9-0-0-rc1-cmake-policy-error-using-cmake-3-9-3/2976 "2020-04-07T17:17:40Z")

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Linux, rhel7, CMake 3.9.3, I passed no args to CMake, and configure fails with this error: CMake Error at ThirdParty/hdf5/CMakeLists.txt:2 (cmake\_policy): Policy “CMP0074” is not known to this version of CMake.

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## [Multiplanar Reconstruction(MPR) for CORONAL images](https://discourse.vtk.org/t/multiplanar-reconstruction-mpr-for-coronal-images/2973)

<div class="topic-metadata">

**Author:** [@Satwik](https://discourse.vtk.org/u/Satwik)\
**Replies:** 0\
**Last updated:** [April 7, 2020, 10:32am UTC](https://discourse.vtk.org/t/multiplanar-reconstruction-mpr-for-coronal-images/2973 "2020-04-07T10:32:41Z")

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Hello everyone, I’m having images which are actually CORONAL acquired. How can i get axial and sagittal transformation matrix like angle of rotation or direction of rotation from CORONAL acquired images. Regards, Sat…

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## [VTK conflict with QT webengine...? \[closed\]](https://discourse.vtk.org/t/vtk-conflict-with-qt-webengine-closed/2971)

<div class="topic-metadata">

**Author:** [@rdbrn](https://discourse.vtk.org/u/rdbrn)\
**Replies:** 1\
**Last updated:** [April 7, 2020, 6:54am UTC](https://discourse.vtk.org/t/vtk-conflict-with-qt-webengine-closed/2971 "2020-04-07T06:54:41Z")

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I ran into quite an obscure problem with the combination of VTK and a Qt WebEngine. Not sure if it is a QT or a VTK problem (or both). To avoid double posts I link here to the post on the qt forum: https://forum.qt.io/t…

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## [set up pipeline and only change the input data](https://discourse.vtk.org/t/set-up-pipeline-and-only-change-the-input-data/2954)

<div class="topic-metadata">

**Author:** [@kayarre](https://discourse.vtk.org/u/kayarre)\
**Replies:** 4\
**Last updated:** [April 6, 2020, 9:54pm UTC](https://discourse.vtk.org/t/set-up-pipeline-and-only-change-the-input-data/2954 "2020-04-06T21:54:50Z")

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I am very used to the idea of pipelines in vtk, but I end up follow this convention for a loop I have always been unclear on the proper way to use them, some filters allow and others don’t? can the pipelines recursivel…

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## [Backfaces showing through & other (z-buffer?) oddities when using vtk8.2](https://discourse.vtk.org/t/backfaces-showing-through-other-z-buffer-oddities-when-using-vtk8-2/2939)

<div class="topic-metadata">

**Author:** [@geoffw](https://discourse.vtk.org/u/geoffw)\
**Replies:** 4\
**Last updated:** [April 6, 2020, 6:07pm UTC](https://discourse.vtk.org/t/backfaces-showing-through-other-z-buffer-oddities-when-using-vtk8-2/2939 "2020-04-06T18:07:27Z")

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Hi, We have recently migrated from vtk8.1 to vtk8.2. We immediately noticed some z-fighting going on between 3d geometries and 2d regions that are “attached” to the surfaces (each polydata has a separate actor). In vtk8…

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## [VTK Gradient Filter](https://discourse.vtk.org/t/vtk-gradient-filter/2961)

<div class="topic-metadata">

**Author:** [@RSwn](https://discourse.vtk.org/u/RSwn)\
**Replies:** 6\
**Last updated:** [April 6, 2020, 3:22pm UTC](https://discourse.vtk.org/t/vtk-gradient-filter/2961 "2020-04-06T15:22:45Z")

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I am using the vtkGradientFilter in Python in order to compute velocity gradients from a vtkUnstructuredGrid file with a snippet shown below. However, when visualised in Paraview the results seem quite blocky and coarse.…

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## [Use VTK](https://discourse.vtk.org/t/use-vtk/2943)

<div class="topic-metadata">

**Author:** [@1117](https://discourse.vtk.org/u/1117)\
**Replies:** 2\
**Last updated:** [April 6, 2020, 1:48pm UTC](https://discourse.vtk.org/t/use-vtk/2943 "2020-04-06T13:48:33Z")

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Hi, I am new in VTK and Python. I need to show a 3D image in python with VTK. This file is a nrrd file. please help me. Thanks

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## [How to fix the font actor size, that is, the font size does not change when the camera distance is changed](https://discourse.vtk.org/t/how-to-fix-the-font-actor-size-that-is-the-font-size-does-not-change-when-the-camera-distance-is-changed/2965)

<div class="topic-metadata">

**Author:** [@kknnnyy](https://discourse.vtk.org/u/kknnnyy)\
**Replies:** 3\
**Last updated:** [April 6, 2020, 12:33pm UTC](https://discourse.vtk.org/t/how-to-fix-the-font-actor-size-that-is-the-font-size-does-not-change-when-the-camera-distance-is-changed/2965 "2020-04-06T12:33:29Z")

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I need to make the text face the camera, so I tried two methods vtkVectorText + vtkFollower This method cannot have a fixed font size like vtkTextActor vtkTextActor It is a vtkActor2D object, this method can not set …

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## [How to use VTK to realize volume rendering in the application based on OpenSceneGraph](https://discourse.vtk.org/t/how-to-use-vtk-to-realize-volume-rendering-in-the-application-based-on-openscenegraph/2327)

<div class="topic-metadata">

**Author:** [@yuhuimoon](https://discourse.vtk.org/u/yuhuimoon)\
**Replies:** 5\
**Last updated:** [April 6, 2020, 12:05pm UTC](https://discourse.vtk.org/t/how-to-use-vtk-to-realize-volume-rendering-in-the-application-based-on-openscenegraph/2327 "2020-04-06T12:05:11Z")

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I’m a beginner of VTK. My 3D application is based on OpenSceneGraph(OSG). Now I want to add volume rendering into the application so that it can convert CT/MRI images to 3D scene. But the volume rendering of OSG is too s…

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## [Segmentation on 3D DICOM ultrasound fetus image](https://discourse.vtk.org/t/segmentation-on-3d-dicom-ultrasound-fetus-image/2953)

<div class="topic-metadata">

**Author:** [@RomyM](https://discourse.vtk.org/u/RomyM)\
**Replies:** 1\
**Last updated:** [April 6, 2020, 11:36am UTC](https://discourse.vtk.org/t/segmentation-on-3d-dicom-ultrasound-fetus-image/2953 "2020-04-06T11:36:48Z")

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Hello, I am new to VTK (and ITK) and I succesfully visualized with volume rendering my 3D dataset. However, I now only want to show the fetus and the placental volume. So I want to segment the fetus and the placenta, an…

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## [render 2D content in QVTKOpenGLNativeWidget](https://discourse.vtk.org/t/render-2d-content-in-qvtkopenglnativewidget/2964)

<div class="topic-metadata">

**Author:** [@yuhuimoon](https://discourse.vtk.org/u/yuhuimoon)\
**Replies:** 4\
**Last updated:** [April 6, 2020, 8:32am UTC](https://discourse.vtk.org/t/render-2d-content-in-qvtkopenglnativewidget/2964 "2020-04-06T08:32:29Z")

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I have a question puzzles me for a long time. The class FormResliceViewer derives from QVTKOpenGLNativeWidget. vtkResliceImageViewer is used, with SetRenderWindow() by the FormResliceViewer object. Image reslice can be …

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## [Using vtkChartXY with vtkMFCWindow](https://discourse.vtk.org/t/using-vtkchartxy-with-vtkmfcwindow/2959)

<div class="topic-metadata">

**Author:** [@dwventer](https://discourse.vtk.org/u/dwventer)\
**Replies:** 1\
**Last updated:** [April 6, 2020, 4:24am UTC](https://discourse.vtk.org/t/using-vtkchartxy-with-vtkmfcwindow/2959 "2020-04-06T04:24:45Z")

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So I found plenty of examples where I can plot a chart using something like the vtkChartXY and vtkContextView object. Something like “pvtContextViewChart-\>GetScene()-\>AddItem(pvtChart);” is needed. Can something please …

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## [Output video of vtkFFMPEGWriter/any video writer plays too fast](https://discourse.vtk.org/t/output-video-of-vtkffmpegwriter-any-video-writer-plays-too-fast/2942)

<div class="topic-metadata">

**Author:** [@Jafari](https://discourse.vtk.org/u/Jafari)\
**Replies:** 5\
**Last updated:** [April 3, 2020, 4:06pm UTC](https://discourse.vtk.org/t/output-video-of-vtkffmpegwriter-any-video-writer-plays-too-fast/2942 "2020-04-03T16:06:57Z")

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Hi All, Environment: VTK 8.2 .NET 4.5.2 Windows 10 Using VTK 8.2, the output video from all video writers (vtkAVIWriter, vtkOggTheoraWriter, and my preference vtkFFMPEGWriter) plays too fast. It seems that frame rat…

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## [IntersectWithLine pure 2D](https://discourse.vtk.org/t/intersectwithline-pure-2d/2945)

<div class="topic-metadata">

**Author:** [@a-jp1](https://discourse.vtk.org/u/a-jp1)\
**Replies:** 1\
**Last updated:** [April 2, 2020, 4:38pm UTC](https://discourse.vtk.org/t/intersectwithline-pure-2d/2945 "2020-04-02T16:38:30Z")

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Hi, I’ve used various trees within the vtk api for quite sometime and many of the FindCell\* and IntersectWith\* type functions to great success for 3D meshes. I have a pure 2D mesh now, quads only. Produced from vtkCel…

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## [AttributeError: 'module' object has no attribute 'vtkVolumeTextureMapper3D'](https://discourse.vtk.org/t/attributeerror-module-object-has-no-attribute-vtkvolumetexturemapper3d/2931)

<div class="topic-metadata">

**Author:** [@1117](https://discourse.vtk.org/u/1117)\
**Replies:** 3\
**Last updated:** [April 2, 2020, 1:51pm UTC](https://discourse.vtk.org/t/attributeerror-module-object-has-no-attribute-vtkvolumetexturemapper3d/2931 "2020-04-02T13:51:11Z")

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Hi, What is this error and how to fix it (in python 3.7.6)? thanks

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## [Missing Qt dll](https://discourse.vtk.org/t/missing-qt-dll/2935)

<div class="topic-metadata">

**Author:** [@Tracy\_Nk](https://discourse.vtk.org/u/Tracy_Nk)\
**Replies:** 6\
**Last updated:** [April 2, 2020, 12:17pm UTC](https://discourse.vtk.org/t/missing-qt-dll/2935 "2020-04-02T12:17:29Z")

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I’m running one of the VTK Qt examples and I’m not sure if I’m doing this correctly. I’ve configured and generated on CMake, then built on Visual Studio, then used Command Prompt to open the executable file however I get…

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## [Can surface scalar data be stored on a vtkUnstructuredGrid?](https://discourse.vtk.org/t/can-surface-scalar-data-be-stored-on-a-vtkunstructuredgrid/2938)

<div class="topic-metadata">

**Author:** [@vchan1186](https://discourse.vtk.org/u/vchan1186)\
**Replies:** 3\
**Last updated:** [April 2, 2020, 2:51am UTC](https://discourse.vtk.org/t/can-surface-scalar-data-be-stored-on-a-vtkunstructuredgrid/2938 "2020-04-02T02:51:39Z")

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Dear VTK experts, Is it possible to visualize scalar attributes on the faces of a vtkUnstructuredGrid, which also contains scalar attributes at each cell? Currently, I am outputting two separate files for storing the un…

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## [units of vtkNIFTIheader.GetPixDim()](https://discourse.vtk.org/t/units-of-vtkniftiheader-getpixdim/2929)

<div class="topic-metadata">

**Author:** [@msmerps](https://discourse.vtk.org/u/msmerps)\
**Replies:** 2\
**Last updated:** [April 2, 2020, 2:32am UTC](https://discourse.vtk.org/t/units-of-vtkniftiheader-getpixdim/2929 "2020-04-02T02:32:12Z")

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Hi all, I am using vtkNIFTIheader.GetPixDim() to get the spacing of NIFTI files. Can I assume that values it returns are in units of millimeters? thank you in advance, -Merps

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## [iOS framework](https://discourse.vtk.org/t/ios-framework/1607)

<div class="topic-metadata">

**Author:** [@leon](https://discourse.vtk.org/u/leon)\
**Replies:** 10\
**Last updated:** [April 2, 2020, 12:05am UTC](https://discourse.vtk.org/t/ios-framework/1607 "2020-04-02T00:05:12Z")

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I want to use VTK in ios. According to the instructions, I plan to Build the vtk.framework of ios, but it is prompted in make that VTK not installed. Build the source then Build the ‘install’ target。The vtk.framework gen…

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