# Support

**URL:** https://discourse.vtk.org/c/support/6.md?page=144

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

**Page:** 145

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## [How to save the vtkPoints to CSV file format?](https://discourse.vtk.org/t/how-to-save-the-vtkpoints-to-csv-file-format/2115)

<div class="topic-metadata">

**Author:** [@Kim\_William](https://discourse.vtk.org/u/Kim_William)\
**Replies:** 6\
**Last updated:** [December 4, 2019, 2:14am UTC](https://discourse.vtk.org/t/how-to-save-the-vtkpoints-to-csv-file-format/2115 "2019-12-04T02:14:23Z")

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Hi all :slight\_smile: I have a question about vtkPoints to CSV file format. My code is: vtkNew m\_vtkPLYReader; vtkNew m\_vtkPCDPoints; m\_vtkPLYReader-\>SetFileName(path.c\_str()); // Load ply file m\_vtkPLYReader-\>Updat…

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## [How can I extract a polygon with the same shape as a 3d glyph?](https://discourse.vtk.org/t/how-can-i-extract-a-polygon-with-the-same-shape-as-a-3d-glyph/2205)

<div class="topic-metadata">

**Author:** [@rjsgml5698](https://discourse.vtk.org/u/rjsgml5698)\
**Replies:** 0\
**Last updated:** [December 4, 2019, 2:09am UTC](https://discourse.vtk.org/t/how-can-i-extract-a-polygon-with-the-same-shape-as-a-3d-glyph/2205 "2019-12-04T02:09:12Z")

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I tried running the vtp example via the following link. https://vtk.org/Wiki/VTK/Examples/Cxx/IO/WriteVTP However, paraview of the output of .vtp shows 3d glyphs. But points and the surface seem to be completely differ…

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## [How to tell if vtkCutter is empty?](https://discourse.vtk.org/t/how-to-tell-if-vtkcutter-is-empty/2203)

<div class="topic-metadata">

**Author:** [@msmerps](https://discourse.vtk.org/u/msmerps)\
**Replies:** 0\
**Last updated:** [December 3, 2019, 6:20pm UTC](https://discourse.vtk.org/t/how-to-tell-if-vtkcutter-is-empty/2203 "2019-12-03T18:20:08Z")

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Hi everyone, I’m using vtkCutter to compute the intersection of a plane and sphere. Is there a good way for me to determine if they don’t intersect at all? thank you in advance, -Merps

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## [Best VR headsets to use with VTK?](https://discourse.vtk.org/t/best-vr-headsets-to-use-with-vtk/2196)

<div class="topic-metadata">

**Author:** [@msmerps](https://discourse.vtk.org/u/msmerps)\
**Replies:** 3\
**Last updated:** [December 3, 2019, 4:07pm UTC](https://discourse.vtk.org/t/best-vr-headsets-to-use-with-vtk/2196 "2019-12-03T16:07:02Z")

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Hi all, I’m interested in using VTK with a virtual reality headset but I don’t know which kind of headset I should buy. Based on this Kitware blog post from 2018 (https://blog.kitware.com/slicervirtualreality/), it seem…

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## [How to create a categorical legend?](https://discourse.vtk.org/t/how-to-create-a-categorical-legend/2195)

<div class="topic-metadata">

**Author:** [@michael23](https://discourse.vtk.org/u/michael23)\
**Replies:** 1\
**Last updated:** [December 2, 2019, 11:06pm UTC](https://discourse.vtk.org/t/how-to-create-a-categorical-legend/2195 "2019-12-02T23:06:38Z")

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Hi, I would like to use the class “vtkCategoryLegend” to add a legend in the lower right corner of my render window. Is there any example of how to use this class? Similar to the “gear type” example I found on the Para…

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## [How to stop flickering issue during rotation](https://discourse.vtk.org/t/how-to-stop-flickering-issue-during-rotation/2192)

<div class="topic-metadata">

**Author:** [@Sathiya\_Moorthy](https://discourse.vtk.org/u/Sathiya_Moorthy)\
**Replies:** 0\
**Last updated:** [December 2, 2019, 12:03pm UTC](https://discourse.vtk.org/t/how-to-stop-flickering-issue-during-rotation/2192 "2019-12-02T12:03:46Z")

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I have the Vtk RendererWindow, It display a vtkOpenGLActor. It flickers whenever the actor is rotated by mouse movement. Is there any way to prevent this flickering?

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## [How to get the transform matrix from vtkProcrustesAlignmentFilter?](https://discourse.vtk.org/t/how-to-get-the-transform-matrix-from-vtkprocrustesalignmentfilter/2179)

<div class="topic-metadata">

**Author:** [@michaelhogg](https://discourse.vtk.org/u/michaelhogg)\
**Replies:** 2\
**Last updated:** [December 1, 2019, 10:41pm UTC](https://discourse.vtk.org/t/how-to-get-the-transform-matrix-from-vtkprocrustesalignmentfilter/2179 "2019-12-01T22:41:53Z")

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Hi all, I am using vtkProcrustesAlignmentFilter to align 2 polydata objects that have the same number of points. I wanted to get the transform matrix out from this filter. I can do this using the following code: procru…

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## [Timer and Mouse call back connection](https://discourse.vtk.org/t/timer-and-mouse-call-back-connection/2188)

<div class="topic-metadata">

**Author:** [@banikr](https://discourse.vtk.org/u/banikr)\
**Replies:** 0\
**Last updated:** [December 1, 2019, 5:16pm UTC](https://discourse.vtk.org/t/timer-and-mouse-call-back-connection/2188 "2019-12-01T17:16:59Z")

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What I am trying to do is very simple in concept, but I don’t know how to do it in VTK as a beginner. I have picked up a point in a 3D image using Mousecallback. The point I am calling seed point gives me world coordina…

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## [vtkSliderWidget doesn't display in my render window python](https://discourse.vtk.org/t/vtksliderwidget-doesnt-display-in-my-render-window-python/2186)

<div class="topic-metadata">

**Author:** [@kimia.af1998](https://discourse.vtk.org/u/kimia.af1998)\
**Replies:** 0\
**Last updated:** [November 30, 2019, 2:24pm UTC](https://discourse.vtk.org/t/vtksliderwidget-doesnt-display-in-my-render-window-python/2186 "2019-11-30T14:24:04Z")

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Hi I have four QVTKRenderWindowInteractor and wants to add a slider into 3 of them. These sliders help to slide through slices. I cannot insert the slider into my render windows. I get this Error : and Here is my…

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## [TimerCallBack and MouseCallBack](https://discourse.vtk.org/t/timercallback-and-mousecallback/2185)

<div class="topic-metadata">

**Author:** [@banikr](https://discourse.vtk.org/u/banikr)\
**Replies:** 3\
**Last updated:** [November 30, 2019, 3:50am UTC](https://discourse.vtk.org/t/timercallback-and-mousecallback/2185 "2019-11-30T03:50:09Z")

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Hello all, I am working on TImerCallback and MouseCallback. In my MouseCallback I choose a point(seedPoint) with mouse click in a glyph3D field. It creates a sphere in the seedPoint. Now the glyphfields has vectors an…

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## [OpenGL2 / Glew error with vtk8.2 in PyCharm](https://discourse.vtk.org/t/opengl2-glew-error-with-vtk8-2-in-pycharm/2181)

<div class="topic-metadata">

**Author:** [@Voidling](https://discourse.vtk.org/u/Voidling)\
**Replies:** 0\
**Last updated:** [November 29, 2019, 1:01am UTC](https://discourse.vtk.org/t/opengl2-glew-error-with-vtk8-2-in-pycharm/2181 "2019-11-29T01:01:17Z")

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Hello, i am facing an issue where i find no adequate help in several online forums. What i did so far is pretty simpel: Using PyCharm IDE Created Conda Python3.7 venv installed vtk package (8.2.0) via conda, which w…

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## [How to convert from 2D polygons (vtkPolydata) to a 3D volumen](https://discourse.vtk.org/t/how-to-convert-from-2d-polygons-vtkpolydata-to-a-3d-volumen/2175)

<div class="topic-metadata">

**Author:** [@vacingforo](https://discourse.vtk.org/u/vacingforo)\
**Replies:** 1\
**Last updated:** [November 28, 2019, 8:47pm UTC](https://discourse.vtk.org/t/how-to-convert-from-2d-polygons-vtkpolydata-to-a-3d-volumen/2175 "2019-11-28T20:47:38Z")

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How to convert from 2D polygons (vtkPolydata) to a 3D volumen? Check the following image:

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## [VTK blend color in wierd way with vtkassembly](https://discourse.vtk.org/t/vtk-blend-color-in-wierd-way-with-vtkassembly/2149)

<div class="topic-metadata">

**Author:** [@lainegates](https://discourse.vtk.org/u/lainegates)\
**Replies:** 3\
**Last updated:** [November 27, 2019, 9:38am UTC](https://discourse.vtk.org/t/vtk-blend-color-in-wierd-way-with-vtkassembly/2149 "2019-11-27T09:38:49Z")

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When I update VTK to version 8.2.0, I encounter a specical bug that VTK will blend color with ‘vtkAssembly’ in wierd way comparing to behavior by vtkActor . While blend color with vtkAssembly, it seems that VTK just ad…

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## [How to use vtk with a scenegraph](https://discourse.vtk.org/t/how-to-use-vtk-with-a-scenegraph/2160)

<div class="topic-metadata">

**Author:** [@scotsman60](https://discourse.vtk.org/u/scotsman60)\
**Replies:** 3\
**Last updated:** [November 27, 2019, 9:30pm UTC](https://discourse.vtk.org/t/how-to-use-vtk-with-a-scenegraph/2160 "2019-11-27T21:30:46Z")

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Hello!!! I have a need to integrate vtk with a scenegraph. My application is display of hierarchical (think CAD Assembly/Part) models where I have lots of ‘Parts’ that contain 1D, 2D and 3D meshes that I currently displ…

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## [point picking in .vtk file](https://discourse.vtk.org/t/point-picking-in-vtk-file/2171)

<div class="topic-metadata">

**Author:** [@banikr](https://discourse.vtk.org/u/banikr)\
**Replies:** 0\
**Last updated:** [November 27, 2019, 6:44pm UTC](https://discourse.vtk.org/t/point-picking-in-vtk-file/2171 "2019-11-27T18:44:18Z")

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Hello all, I am working with a .vtk file of the brain which consists of principal eigenvectors. Please see the thresholded brain image and zoomed up version(glyphs) in the images. Now I want to pick a seed point in…

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## [Errors on a very simple ITK+VTK+Qt program](https://discourse.vtk.org/t/errors-on-a-very-simple-itk-vtk-qt-program/2169)

<div class="topic-metadata">

**Author:** [@BorisM](https://discourse.vtk.org/u/BorisM)\
**Replies:** 0\
**Last updated:** [November 27, 2019, 4:53pm UTC](https://discourse.vtk.org/t/errors-on-a-very-simple-itk-vtk-qt-program/2169 "2019-11-27T16:53:37Z")

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I am new to ITK/VTK programming. I have written a very simple program using ITK,VTK and Qt, inspired from VTK examples (mainly Examples/GUI/Qt/FourPaneViewer). It simply allows to visualize a 3D image, loaded via ITK. I…

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## [vtkLinearExtrusionFilter does not extrude all faces only the basis](https://discourse.vtk.org/t/vtklinearextrusionfilter-does-not-extrude-all-faces-only-the-basis/2151)

<div class="topic-metadata">

**Author:** [@zandarina](https://discourse.vtk.org/u/zandarina)\
**Replies:** 1\
**Last updated:** [November 27, 2019, 10:49am UTC](https://discourse.vtk.org/t/vtklinearextrusionfilter-does-not-extrude-all-faces-only-the-basis/2151 "2019-11-27T10:49:09Z")

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Hi everybody, I want to extrude towards (0,0,-1) down. But i have realized that linear extrusion filter only extrudes the basis of the stl as the image shows. I wonder if there is a filter that considers all the faces a…

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## [Advice for high-quality anti-aliased lines + volume rendering](https://discourse.vtk.org/t/advice-for-high-quality-anti-aliased-lines-volume-rendering/2141)

<div class="topic-metadata">

**Author:** [@estan](https://discourse.vtk.org/u/estan)\
**Replies:** 10\
**Last updated:** [November 27, 2019, 7:52am UTC](https://discourse.vtk.org/t/advice-for-high-quality-anti-aliased-lines-volume-rendering/2141 "2019-11-27T07:52:15Z")

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Hi all, We’re running with multi-sampling disabled since it’s problematic when combined with volume rendering on Intel GPUs (GL errors/black screen). Instead we use FXAA with default settings to at least get some anti-…

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## [Reading and visualizing vtk file](https://discourse.vtk.org/t/reading-and-visualizing-vtk-file/2158)

<div class="topic-metadata">

**Author:** [@banikr](https://discourse.vtk.org/u/banikr)\
**Replies:** 1\
**Last updated:** [November 26, 2019, 10:36pm UTC](https://discourse.vtk.org/t/reading-and-visualizing-vtk-file/2158 "2019-11-26T22:36:10Z")

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Hello all, I am trying to read a DTIbrain file in .vtk format. The image has eigenvectors and eigenvalues attached to its voxels and I want to read and visualize the principal eigenvectors. For this, I am using vtkStru…

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## [Errors in running code(Segmentation fault(core dumped) and vtkPolyDataMapper)](https://discourse.vtk.org/t/errors-in-running-code-segmentation-fault-core-dumped-and-vtkpolydatamapper/2146)

<div class="topic-metadata">

**Author:** [@banikr](https://discourse.vtk.org/u/banikr)\
**Replies:** 4\
**Last updated:** [November 26, 2019, 11:20am UTC](https://discourse.vtk.org/t/errors-in-running-code-segmentation-fault-core-dumped-and-vtkpolydatamapper/2146 "2019-11-26T11:20:15Z")

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I am getting this strange error when I am running my VTK codes(C++) banikr@banikr:~/VTK/VTKTract1-build$ ./VTKTract1 Here@@@@@ 2019-11-25 15:08:43.910 ( 0.243s) \[ 554C4740\] vtkPolyDataMapper.cxx:…

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## [Extract principal eigenvectors from diffusion tensor image](https://discourse.vtk.org/t/extract-principal-eigenvectors-from-diffusion-tensor-image/2129)

<div class="topic-metadata">

**Author:** [@banikr](https://discourse.vtk.org/u/banikr)\
**Replies:** 4\
**Last updated:** [November 25, 2019, 11:42pm UTC](https://discourse.vtk.org/t/extract-principal-eigenvectors-from-diffusion-tensor-image/2129 "2019-11-25T23:42:09Z")

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Hello all, I am a beginner in VTK. I have a brainDTI image in .nrrd format. I want to extract the principal eigenvalues from the that image and create a separate vector image. First of all, I tried reading the .nrrd i…

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## [ospray backend from vtk python](https://discourse.vtk.org/t/ospray-backend-from-vtk-python/2128)

<div class="topic-metadata">

**Author:** [@gilcu2](https://discourse.vtk.org/u/gilcu2)\
**Replies:** 4\
**Last updated:** [November 25, 2019, 3:34pm UTC](https://discourse.vtk.org/t/ospray-backend-from-vtk-python/2128 "2019-11-25T15:34:50Z")

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Hello, is possible use the ospray backend from vtk python? If yes can you explain or point to some example? Thanks Reynaldo

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## [Complete VTK build? (except modules depending on external libraries)](https://discourse.vtk.org/t/complete-vtk-build-except-modules-depending-on-external-libraries/2125)

<div class="topic-metadata">

**Author:** [@cesss](https://discourse.vtk.org/u/cesss)\
**Replies:** 2\
**Last updated:** [November 23, 2019, 11:54am UTC](https://discourse.vtk.org/t/complete-vtk-build-except-modules-depending-on-external-libraries/2125 "2019-11-23T11:54:24Z")

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I’m using the master branch. I wasn’t able to find info on how to do a complete build of VTK (that is, excluding modules depending on external libs). After running ccmake iteratively, as explained in the documentation, I…

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## [vtkWrapPython disappeared from VTK-8.90](https://discourse.vtk.org/t/vtkwrappython-disappeared-from-vtk-8-90/2084)

<div class="topic-metadata">

**Author:** [@lassoan](https://discourse.vtk.org/u/lassoan)\
**Replies:** 14\
**Last updated:** [November 22, 2019, 4:05pm UTC](https://discourse.vtk.org/t/vtkwrappython-disappeared-from-vtk-8-90/2084 "2019-11-22T16:05:11Z")

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In 3D Slicer’s build system we rely on vtkWrapHierarchy.cmake and vtkWrapPython.cmake to wrap our VTK-based C++ classes. However, these macros seem to be refactored into a new macro, vtkModuleWrapPython.cmake. We already…

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## [Any specially recommended commit point for building VTK with GLTF support?](https://discourse.vtk.org/t/any-specially-recommended-commit-point-for-building-vtk-with-gltf-support/2118)

<div class="topic-metadata">

**Author:** [@cesss](https://discourse.vtk.org/u/cesss)\
**Replies:** 2\
**Last updated:** [November 21, 2019, 3:07pm UTC](https://discourse.vtk.org/t/any-specially-recommended-commit-point-for-building-vtk-with-gltf-support/2118 "2019-11-21T15:07:41Z")

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Hi! I just downloaded 8.2.0 for using the new GLTF support, but then I realized it’s not yet there. So, I’m guessing there’s no official release yet with GLTF support. From the development forum, I guess there’s no goin…

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## [Is it possible to build VTK as both static and dynamic libs](https://discourse.vtk.org/t/is-it-possible-to-build-vtk-as-both-static-and-dynamic-libs/2119)

<div class="topic-metadata">

**Author:** [@cesss](https://discourse.vtk.org/u/cesss)\
**Replies:** 2\
**Last updated:** [November 21, 2019, 3:02pm UTC](https://discourse.vtk.org/t/is-it-possible-to-build-vtk-as-both-static-and-dynamic-libs/2119 "2019-11-21T15:02:42Z")

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If I enable BUILD\_SHARED\_LIBS, then static libs are not built. Is it possible to build both dynamic and static? (I need both: dynamic for lab tests, and static for app release to third parties). Thanks a lot! cesss

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## [Tetrahedron with texture without scalars](https://discourse.vtk.org/t/tetrahedron-with-texture-without-scalars/2112)

<div class="topic-metadata">

**Author:** [@aries24](https://discourse.vtk.org/u/aries24)\
**Replies:** 0\
**Last updated:** [November 20, 2019, 8:36pm UTC](https://discourse.vtk.org/t/tetrahedron-with-texture-without-scalars/2112 "2019-11-20T20:36:01Z")

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I am trying to create a tetrahedron with a JPEG images on its faces. I have thought of two approaches: Use the vtkPlatonicSolidSource and set the type to Tetrahedron. However, when I try to set my vtkTexture to the ac…

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## [How to cut a surface along a closed polyline?](https://discourse.vtk.org/t/how-to-cut-a-surface-along-a-closed-polyline/2099)

<div class="topic-metadata">

**Author:** [@normanius](https://discourse.vtk.org/u/normanius)\
**Replies:** 1\
**Last updated:** [November 19, 2019, 3:09pm UTC](https://discourse.vtk.org/t/how-to-cut-a-surface-along-a-closed-polyline/2099 "2019-11-19T15:09:37Z")

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Dear all I’ve got a specific problem, and I wondered how you would solve it. Let’s be given a triangular surface mesh M and a closed poly line L that goes along the edges of M. All points of L coincide with points of M.…

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## [How to tell what version of OpenGL my VTK app is using & Apple's deprecation of OpenGL](https://discourse.vtk.org/t/how-to-tell-what-version-of-opengl-my-vtk-app-is-using-apples-deprecation-of-opengl/2093)

<div class="topic-metadata">

**Author:** [@msmerps](https://discourse.vtk.org/u/msmerps)\
**Replies:** 2\
**Last updated:** [November 19, 2019, 3:18am UTC](https://discourse.vtk.org/t/how-to-tell-what-version-of-opengl-my-vtk-app-is-using-apples-deprecation-of-opengl/2093 "2019-11-19T03:18:11Z")

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Hi all, How can I tell which version of OpenGL my VTK app is using? And is VTK performance on recent versions of OSX going to suffer now that Apple no longer supports OpenGL? thank you in advance, -M

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## [Texture issue with GLTF importer](https://discourse.vtk.org/t/texture-issue-with-gltf-importer/2101)

<div class="topic-metadata">

**Author:** [@pbrousson](https://discourse.vtk.org/u/pbrousson)\
**Replies:** 3\
**Last updated:** [November 18, 2019, 1:54pm UTC](https://discourse.vtk.org/t/texture-issue-with-gltf-importer/2101 "2019-11-18T13:54:18Z")

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Hello, I need to import some 3D textured models made with Blender and duplicate them several times. I use the GLTF format. The vtkGLTFImporter works fine with one object (I can duplicate the imported actor) but I encoun…

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