# Latest

**URL:** https://discourse.vtk.org/latest.md?page=231

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

**Page:** 232

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## [Decimation with texture maps](https://discourse.vtk.org/t/decimation-with-texture-maps/2166)

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**Author:** [@Famous](https://discourse.vtk.org/u/Famous)\
**Replies:** 0\
**Last updated:** [November 27, 2019, 3:27pm UTC](https://discourse.vtk.org/t/decimation-with-texture-maps/2166 "2019-11-27T15:27:17Z")

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Hi All, I am looking to extend a VTK based decimation algorithm to support texture maps. I can see that vtkQuadricDecimation class contains functions relating to TCoords e.g. SetTCoordsAttribute(vtkTypeBool), however v…

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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)

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**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)

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**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)

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**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)

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**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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## [3D Reconstruction from 2D X-ray Images](https://discourse.vtk.org/t/3d-reconstruction-from-2d-x-ray-images/2138)

<div class="topic-metadata">

**Author:** [@rjsgml5698](https://discourse.vtk.org/u/rjsgml5698)\
**Replies:** 2\
**Last updated:** [November 26, 2019, 4:12am UTC](https://discourse.vtk.org/t/3d-reconstruction-from-2d-x-ray-images/2138 "2019-11-26T04:12:42Z")

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Can I extract volume data with x-rays? Can only polydata be possible?

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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)

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**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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## [Add support for Apple Metal rendering for macOS and iOS](https://discourse.vtk.org/t/add-support-for-apple-metal-rendering-for-macos-and-ios/1849)

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**Author:** [@hcwiley](https://discourse.vtk.org/u/hcwiley)\
**Replies:** 6\
**Last updated:** [November 24, 2019, 9:06pm UTC](https://discourse.vtk.org/t/add-support-for-apple-metal-rendering-for-macos-and-ios/1849 "2019-11-24T21:06:35Z")

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Has there been any discussion internally at Kitware about Apple’s move as of WWDC 2018 to not support OpenGL any more? Looks like there needs to be a Metal backed rendering system to support this move. I would really …

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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)

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**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)

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**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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## [Trouble using VTK Widget with QVTK](https://discourse.vtk.org/t/trouble-using-vtk-widget-with-qvtk/2110)

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**Author:** [@Andreimd02](https://discourse.vtk.org/u/Andreimd02)\
**Replies:** 3\
**Last updated:** [November 22, 2019, 2:38pm UTC](https://discourse.vtk.org/t/trouble-using-vtk-widget-with-qvtk/2110 "2019-11-22T14:38:36Z")

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Hi, guys, So, I’m have a trouble to use QVTKRenderWindowInteractor and vtkContourWidget I have this program This is how I made it: class SimulationWindow(QMainWindow): def init(self): super().init() self.initWin…

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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)

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**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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## [Calculation of 4x4 matrix of planes](https://discourse.vtk.org/t/calculation-of-4x4-matrix-of-planes/1423)

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**Author:** [@1111](https://discourse.vtk.org/u/1111)\
**Replies:** 14\
**Last updated:** [November 21, 2019, 2:31pm UTC](https://discourse.vtk.org/t/calculation-of-4x4-matrix-of-planes/1423 "2019-11-21T14:31:10Z")

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Hi, I am using the example of ImplicitPlaneWidget2. I want to be able to manipulate this by inputting a 3D image (.raw). I studied about 4x4 matrix. I would like to write a program to calculate 4x4 matrix in plane. T…

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

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**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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## [Clang format discussion](https://discourse.vtk.org/t/clang-format-discussion/2073)

<div class="topic-metadata">

**Author:** [@ben.boeckel](https://discourse.vtk.org/u/ben.boeckel)\
**Replies:** 40\
**Last updated:** [November 20, 2019, 7:38pm UTC](https://discourse.vtk.org/t/clang-format-discussion/2073 "2019-11-20T19:38:56Z")

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At the hackathon this week, there was discussion of using clang-format on VTK to enforce coding style guidelines. This allows formatting of a merge request using Do: reformat so that local formatting isn’t necessary (and…

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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)

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**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)

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**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)

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**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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## [The dragging is not working with 'WindowInteractor'.](https://discourse.vtk.org/t/the-dragging-is-not-working-with-windowinteractor/2090)

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**Author:** [@Kim\_William](https://discourse.vtk.org/u/Kim_William)\
**Replies:** 1\
**Last updated:** [November 18, 2019, 6:14am UTC](https://discourse.vtk.org/t/the-dragging-is-not-working-with-windowinteractor/2090 "2019-11-18T06:14:06Z")

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Hi all. I have tested the Line Plot with VTK 8.9 on MFC. I referred to the sample code as below: https://lorensen.github.io/VTKExamples/site/Cxx/Plotting/LinePlot/ Initially, I can drag by clicking the mouse left but…

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## [Extracting regions as PolyData](https://discourse.vtk.org/t/extracting-regions-as-polydata/1788)

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**Author:** [@Srihitha](https://discourse.vtk.org/u/Srihitha)\
**Replies:** 11\
**Last updated:** [November 15, 2019, 11:54pm UTC](https://discourse.vtk.org/t/extracting-regions-as-polydata/1788 "2019-11-15T23:54:34Z")

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Hi, I am having a polydata containing multiple regions. I want to extract these regions as individual polydata. Using “vtkPolyDataConnectivityFilter”, I am able to get the total count of extracted regions and able to v…

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## [vtkChartXY - Log Scaling X](https://discourse.vtk.org/t/vtkchartxy-log-scaling-x/2094)

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**Author:** [@ChristopherWaters](https://discourse.vtk.org/u/ChristopherWaters)\
**Replies:** 1\
**Last updated:** [November 16, 2019, 8:56am UTC](https://discourse.vtk.org/t/vtkchartxy-log-scaling-x/2094 "2019-11-16T08:56:28Z")

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I have a vtkChartXY and have no idea how to enable log scaling of the x-axis. The y-axis is easy, just requiring: chart-\>GetAxis(vtkAxis::LEFT)-\>LogScaleOn(); The x-axis is another story, since it is based off of th…

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## [Goodbye GetVoidPointer: Using ArrayDispatch and DataArrayRanges](https://discourse.vtk.org/t/goodbye-getvoidpointer-using-arraydispatch-and-dataarrayranges/2097)

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**Author:** [@allison.vacanti](https://discourse.vtk.org/u/allison.vacanti)\
**Replies:** 2\
**Last updated:** [November 14, 2019, 11:36pm UTC](https://discourse.vtk.org/t/goodbye-getvoidpointer-using-arraydispatch-and-dataarrayranges/2097 "2019-11-14T23:36:00Z")

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One of the topics discussed at the hackathon involved deprecating vtkDataArray::GetVoidPointer. While this is not likely to happen for a while, we’ve agreed to stop using GetVoidPointer and vtkTemplateMacro in new code, …

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## [File format for polyhedron unstructured grid data](https://discourse.vtk.org/t/file-format-for-polyhedron-unstructured-grid-data/1914)

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**Author:** [@tkeskita](https://discourse.vtk.org/u/tkeskita)\
**Replies:** 1\
**Last updated:** [November 14, 2019, 10:45am UTC](https://discourse.vtk.org/t/file-format-for-polyhedron-unstructured-grid-data/1914 "2019-11-14T10:45:37Z")

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Hello, I’d like to write an exporter of 3D unstructured volume grids (cells composed of arbitrary shapes of polyhedrons, serial data format) to export the 3D grid to VTK. I guess my options include the XML Unstructured …

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## [CT vs MRI reading](https://discourse.vtk.org/t/ct-vs-mri-reading/2095)

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**Author:** [@flaviu2](https://discourse.vtk.org/u/flaviu2)\
**Replies:** 0\
**Last updated:** [November 14, 2019, 9:39am UTC](https://discourse.vtk.org/t/ct-vs-mri-reading/2095 "2019-11-14T09:39:39Z")

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Is there any difference between read DICOM CT data or DICOM MRI data ? I have written code that read DICOM data and represent it as vtkVolume. I used DICOM VTK library for that (https://github.com/dgobbi/vtk-dicom) (BTW,…

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## [How to decide between QVTKOpenGL{Native}Widget?](https://discourse.vtk.org/t/how-to-decide-between-qvtkopengl-native-widget/1070)

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**Author:** [@estan](https://discourse.vtk.org/u/estan)\
**Replies:** 8\
**Last updated:** [November 13, 2019, 10:17pm UTC](https://discourse.vtk.org/t/how-to-decide-between-qvtkopengl-native-widget/1070 "2019-11-13T22:17:15Z")

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Hi all, The advice in the thread “the New QVTKOpenGLWidget” on the development mailing list read: \*\*1. Why is there a new widget and what does it do ?\*\* We have been having some issues reported for the old widget, and…

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## [Intel UHD 620 + VTK + Qt bug with new drivers on windows](https://discourse.vtk.org/t/intel-uhd-620-vtk-qt-bug-with-new-drivers-on-windows/1694)

<div class="topic-metadata">

**Author:** [@simonesneault](https://discourse.vtk.org/u/simonesneault)\
**Replies:** 14\
**Last updated:** [November 13, 2019, 10:15pm UTC](https://discourse.vtk.org/t/intel-uhd-620-vtk-qt-bug-with-new-drivers-on-windows/1694 "2019-11-13T22:15:28Z")

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Hello community, We are affected by a bug on windows after some recent Intel drivers update (versions superior to 26.20.100.6708). It is no longer possible to have a QVTKOpenGLWidget and a QWebEngineView working in the …

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## [QtOpenGLNativeWidget - here's a simple broken example](https://discourse.vtk.org/t/qtopenglnativewidget-heres-a-simple-broken-example/2089)

<div class="topic-metadata">

**Author:** [@DominionSoftware](https://discourse.vtk.org/u/DominionSoftware)\
**Replies:** 4\
**Last updated:** [November 13, 2019, 8:08pm UTC](https://discourse.vtk.org/t/qtopenglnativewidget-heres-a-simple-broken-example/2089 "2019-11-13T20:08:53Z")

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Here’s a simple example of loading the plastic skull that is similar to Medical4 demo. If someone could see what’s wrong with this code that would be great… Thanks Rick

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## [Export linear extrusion as .ply file](https://discourse.vtk.org/t/export-linear-extrusion-as-ply-file/2092)

<div class="topic-metadata">

**Author:** [@Mskovmand](https://discourse.vtk.org/u/Mskovmand)\
**Replies:** 1\
**Last updated:** [November 13, 2019, 3:04pm UTC](https://discourse.vtk.org/t/export-linear-extrusion-as-ply-file/2092 "2019-11-13T15:04:40Z")

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Hello, I’ve had great luck exporting colored glyphs as .ply files for use in other software. Now I’m trying to export some “cylinders” which are created using a linear extrusion, more specifically, like this: disk = v…

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