# Support

**URL:** https://discourse.vtk.org/c/support/6.md?page=4

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

**Page:** 5

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## [Memory Leak in vtkRenderWindow Render](https://discourse.vtk.org/t/memory-leak-in-vtkrenderwindow-render/15339)

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**Author:** [@mikewho](https://discourse.vtk.org/u/mikewho)\
**Replies:** 24\
**Last updated:** [November 19, 2025, 6:02pm UTC](https://discourse.vtk.org/t/memory-leak-in-vtkrenderwindow-render/15339 "2025-11-19T18:02:16Z")

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I am encountering what appears to be a memory leak when calling Render in a loop for a vtkRenderWindow. See the code below for a minimal example. The size of the leak varies depending on the PC, anywhere from 1 MB to 10 …

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## [vtk 9 line rendering](https://discourse.vtk.org/t/vtk-9-line-rendering/16120)

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**Author:** [@metamurk](https://discourse.vtk.org/u/metamurk)\
**Replies:** 17\
**Last updated:** [November 17, 2025, 12:59pm UTC](https://discourse.vtk.org/t/vtk-9-line-rendering/16120 "2025-11-17T12:59:02Z")

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I upgraded from VTK 8 to VTK 9, and the line rendering quality dropped significantly. VTK 8: Thats the same scene in vt9. Lines look unsharp and have uneven thicknesses: Thats a major showstopper for us at the mo…

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## [QComboBox does not show popup list when over a QVTKOpenGLNativeWidget and fullscreen window](https://discourse.vtk.org/t/qcombobox-does-not-show-popup-list-when-over-a-qvtkopenglnativewidget-and-fullscreen-window/16140)

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**Author:** [@Dresult](https://discourse.vtk.org/u/Dresult)\
**Replies:** 0\
**Last updated:** [November 13, 2025, 9:02am UTC](https://discourse.vtk.org/t/qcombobox-does-not-show-popup-list-when-over-a-qvtkopenglnativewidget-and-fullscreen-window/16140 "2025-11-13T09:02:55Z")

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Hello, I’m trying to embed a 3D model into a Qt window. For that, I’m using the QVTKOpenGLNativeWidget. However, I have to add also a QComboBox in a overlay. The problem is that the QComboBox popup list does not show if…

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## [VTK8.2 Limitation](https://discourse.vtk.org/t/vtk8-2-limitation/16139)

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**Author:** [@OstiumAxioma](https://discourse.vtk.org/u/OstiumAxioma)\
**Replies:** 0\
**Last updated:** [November 13, 2025, 4:45am UTC](https://discourse.vtk.org/t/vtk8-2-limitation/16139 "2025-11-13T04:45:32Z")

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Hi guys, I am currently working on a project with a static library developed based on VTK8.2. And I found out that some of the function I used in VTK9.0 is not available. For example, if I want to read a compressed NIFT…

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## [A tale of 2.5 UIs](https://discourse.vtk.org/t/a-tale-of-2-5-uis/16135)

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**Author:** [@Joe\_Tristano](https://discourse.vtk.org/u/Joe_Tristano)\
**Replies:** 3\
**Last updated:** [November 12, 2025, 4:59pm UTC](https://discourse.vtk.org/t/a-tale-of-2-5-uis/16135 "2025-11-12T16:59:32Z")

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Vtk ui Hello Im writing for those who may find themselves in the same situation as well as for any guidance from the experts I started down a path of writing an interactive vtk application. I am inspired by fui (iro…

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## [how to adjust gl\_pointSize when zoom in/out](https://discourse.vtk.org/t/how-to-adjust-gl-pointsize-when-zoom-in-out/16137)

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**Author:** [@Nam\_Le\_Hoang](https://discourse.vtk.org/u/Nam_Le_Hoang)\
**Replies:** 0\
**Last updated:** [November 12, 2025, 3:50am UTC](https://discourse.vtk.org/t/how-to-adjust-gl-pointsize-when-zoom-in-out/16137 "2025-11-12T03:50:53Z")

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Hi everyone, I have a problem need the support. I’m using vtk with python using vtkInteractorStyleTrackballCamera with the setting \`\` self.interactor\_style = vtk.vtkInteractorStyleTrackballCamera() self.interactor.Se…

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## [VTK DICOM useage](https://discourse.vtk.org/t/vtk-dicom-useage/16129)

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**Author:** [@Ak2333](https://discourse.vtk.org/u/Ak2333)\
**Replies:** 0\
**Last updated:** [November 8, 2025, 3:25am UTC](https://discourse.vtk.org/t/vtk-dicom-useage/16129 "2025-11-08T03:25:26Z")

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Hello, I am just getting into VTK, and I need to render CT-Scans. I would ideally like to able to render 2 CT-Scans within 1 volume. And be able to move them as actors from within the code, not the interactor. I was loo…

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## [How to apply individual scalars/textures to layers when using vtkOpenGLGlyph3DMapper for stacked point clouds?](https://discourse.vtk.org/t/how-to-apply-individual-scalars-textures-to-layers-when-using-vtkopenglglyph3dmapper-for-stacked-point-clouds/16125)

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**Author:** [@guote](https://discourse.vtk.org/u/guote)\
**Replies:** 2\
**Last updated:** [November 7, 2025, 2:22am UTC](https://discourse.vtk.org/t/how-to-apply-individual-scalars-textures-to-layers-when-using-vtkopenglglyph3dmapper-for-stacked-point-clouds/16125 "2025-11-07T02:22:07Z")

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Hi all, I am working with a large point cloud dataset with a shape of (N, 7000), where N is the number of points on a surface, and 7000 represents the number of stacked depth layers for each point. Currently, I can suc…

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## [trame-deckgl OrthographicView](https://discourse.vtk.org/t/trame-deckgl-orthographicview/16126)

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**Author:** [@firinini](https://discourse.vtk.org/u/firinini)\
**Replies:** 2\
**Last updated:** [November 6, 2025, 3:33pm UTC](https://discourse.vtk.org/t/trame-deckgl-orthographicview/16126 "2025-11-06T15:33:34Z")

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Hi, is it possible to use the trame-deckgl widget to plot an overlay of scatter points on image data? I tried both the trame plotly and image-tools widgets for this purpose, but none of them seem very performant when d…

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## [VTK-9.5.0: what is the correct way to use vtkGenericOpenGLRenderWindow with glad?](https://discourse.vtk.org/t/vtk-9-5-0-what-is-the-correct-way-to-use-vtkgenericopenglrenderwindow-with-glad/16121)

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**Author:** [@fghoussen](https://discourse.vtk.org/u/fghoussen)\
**Replies:** 7\
**Last updated:** [November 6, 2025, 2:35pm UTC](https://discourse.vtk.org/t/vtk-9-5-0-what-is-the-correct-way-to-use-vtkgenericopenglrenderwindow-with-glad/16121 "2025-11-06T14:35:26Z")

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VTK-9.5.0: what is the correct way to use vtkGenericOpenGLRenderWindow with glad? I have a application that build from source VTK for an application using vtkGenericOpenGLRenderWindow. Before VTK-9.5.0: glew was used. …

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## [mac 15 m4 chip + glfw + openGL build error](https://discourse.vtk.org/t/mac-15-m4-chip-glfw-opengl-build-error/16123)

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**Author:** [@Analysiszaj](https://discourse.vtk.org/u/Analysiszaj)\
**Replies:** 0\
**Last updated:** [November 5, 2025, 9:48am UTC](https://discourse.vtk.org/t/mac-15-m4-chip-glfw-opengl-build-error/16123 "2025-11-05T09:48:24Z")

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I tried using glfw as my window and then employed it\` vtkSmartPointer\<vtkGenericOpenGLRenderWindow\> renderWindow = vtkSmartPointer\<vtkGenericOpenGLRenderWindow\>::New(); renderWindow-\>InitializeFromCurrentContext…

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## [Paraview silently appearing in latest Nvidia video?](https://discourse.vtk.org/t/paraview-silently-appearing-in-latest-nvidia-video/16119)

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**Author:** [@mau\_igna\_06](https://discourse.vtk.org/u/mau_igna_06)\
**Replies:** 1\
**Last updated:** [November 3, 2025, 8:16am UTC](https://discourse.vtk.org/t/paraview-silently-appearing-in-latest-nvidia-video/16119 "2025-11-03T08:16:03Z")

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The default Paraview’s colormap in used to render physics simulation results made by simulation AI startups backed up by Nvidia? Please see videos below: https://youtu.be/pp843pWaZsg?si=raohipz5TZcpg507&t=…

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## [Brush tool only paints correctly in one view (VTKPolyDataToImageStencil issue?)](https://discourse.vtk.org/t/brush-tool-only-paints-correctly-in-one-view-vtkpolydatatoimagestencil-issue/16114)

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**Author:** [@Midnaaaaaa](https://discourse.vtk.org/u/Midnaaaaaa)\
**Replies:** 6\
**Last updated:** [October 30, 2025, 1:38pm UTC](https://discourse.vtk.org/t/brush-tool-only-paints-correctly-in-one-view-vtkpolydatatoimagestencil-issue/16114 "2025-10-30T13:38:46Z")

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I’m implementing a brush tool for my VTK-based application, which has three 2D views: axial, sagittal, and coronal. The brush works as follows: while the left mouse button is held and the mouse moves, I create a circula…

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## [vtkWindowToImageFilter and Multiple Renderers](https://discourse.vtk.org/t/vtkwindowtoimagefilter-and-multiple-renderers/16111)

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**Author:** [@geoffw](https://discourse.vtk.org/u/geoffw)\
**Replies:** 2\
**Last updated:** [October 28, 2025, 7:45pm UTC](https://discourse.vtk.org/t/vtkwindowtoimagefilter-and-multiple-renderers/16111 "2025-10-28T19:45:42Z")

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Hi, I have trouble with vtkWindowToImageFilter If I have multiple renderers. Just doesn’t render correctly unless I remove all the renderers except one. Not sure why. Just FYI if you have trouble with this filter you mi…

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## [Request for Guidance: Cleaning STL PolyData and Preparing for Smooth Extrusion in VTK](https://discourse.vtk.org/t/request-for-guidance-cleaning-stl-polydata-and-preparing-for-smooth-extrusion-in-vtk/16113)

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**Author:** [@christeen](https://discourse.vtk.org/u/christeen)\
**Replies:** 1\
**Last updated:** [October 28, 2025, 10:03am UTC](https://discourse.vtk.org/t/request-for-guidance-cleaning-stl-polydata-and-preparing-for-smooth-extrusion-in-vtk/16113 "2025-10-28T10:03:48Z")

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Dear VTK Developers, I hope you’re doing well. I’m currently working on loading STL files into VTK and performing extrusion operations based on selected surface regions. Specifically, I select a region by drawing a con…

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## [OpenGL issue](https://discourse.vtk.org/t/opengl-issue/15995)

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**Author:** [@Gilthalas](https://discourse.vtk.org/u/Gilthalas)\
**Replies:** 4\
**Last updated:** [October 23, 2025, 1:23pm UTC](https://discourse.vtk.org/t/opengl-issue/15995 "2025-10-23T13:23:26Z")

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OK, working on getting vtk9.5 (custom build) to work on my M series mac, and running into failures when running. Have narrowed it down to vktOpenGLState failing when calling lines like this: ::glGetFloatv(GL\_DEPTH\_CLEA…

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## [Access regions data of stl subregions after using vtkSTLReader](https://discourse.vtk.org/t/access-regions-data-of-stl-subregions-after-using-vtkstlreader/12001)

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**Author:** [@madmoonman](https://discourse.vtk.org/u/madmoonman)\
**Replies:** 11\
**Last updated:** [October 20, 2025, 11:10am UTC](https://discourse.vtk.org/t/access-regions-data-of-stl-subregions-after-using-vtkstlreader/12001 "2025-10-20T11:10:01Z")

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Hello, I have spent a ton of time trying to figure this out, but I have to admit defeat, so hopefully I can get some guidance here. I am trying to process stl files that are composed of multiple parts, called “solids” i…

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## [CameraOrientationWidget Slow rendering with WASM](https://discourse.vtk.org/t/cameraorientationwidget-slow-rendering-with-wasm/16099)

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**Author:** [@Joe\_Tristano](https://discourse.vtk.org/u/Joe_Tristano)\
**Replies:** 0\
**Last updated:** [October 19, 2025, 12:30pm UTC](https://discourse.vtk.org/t/cameraorientationwidget-slow-rendering-with-wasm/16099 "2025-10-19T12:30:39Z")

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Hi, I have a small trame app where I want some spatial awareness on the screen. Interaction and rotation of my actors is very fast without any spatial awareness widgets. When I add CameraOrientationWidget or if I add …

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## [xyz big values points plot issue](https://discourse.vtk.org/t/xyz-big-values-points-plot-issue/16095)

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**Author:** [@Joaquin\_Opazo](https://discourse.vtk.org/u/Joaquin_Opazo)\
**Replies:** 8\
**Last updated:** [October 16, 2025, 2:35pm UTC](https://discourse.vtk.org/t/xyz-big-values-points-plot-issue/16095 "2025-10-16T14:35:22Z")

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Hi all, I’m currently working on creating meshings for a surface using Delaunay2D for triangulation, but I’ve encountered an issue while reading the xyz points from my file. These are georeferenced points, so they actua…

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## [How to write temporal UnstructuredGrid data to a VTKHDF file with vtkHDFWriter in Python?](https://discourse.vtk.org/t/how-to-write-temporal-unstructuredgrid-data-to-a-vtkhdf-file-with-vtkhdfwriter-in-python/16096)

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**Author:** [@liblaf](https://discourse.vtk.org/u/liblaf)\
**Replies:** 2\
**Last updated:** [October 15, 2025, 3:02pm UTC](https://discourse.vtk.org/t/how-to-write-temporal-unstructuredgrid-data-to-a-vtkhdf-file-with-vtkhdfwriter-in-python/16096 "2025-10-15T15:02:20Z")

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Hi all, I’m trying to write a time series of vtkUnstructuredGrid data to a single VTKHDF (.vtkhdf) file using Python. Specifically, the grid topology is constant, but a point data array named “foo” changes over 100 time…

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## [Trame in subprocess doesnt render wasm. Possible websocket wslink issue](https://discourse.vtk.org/t/trame-in-subprocess-doesnt-render-wasm-possible-websocket-wslink-issue/16087)

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**Author:** [@Joe\_Tristano](https://discourse.vtk.org/u/Joe_Tristano)\
**Replies:** 2\
**Last updated:** [October 10, 2025, 9:44pm UTC](https://discourse.vtk.org/t/trame-in-subprocess-doesnt-render-wasm-possible-websocket-wslink-issue/16087 "2025-10-10T21:44:03Z")

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Based on some reading, and this thread pvd , vtu , vti files with vtk wasm I decided to try and Start trame in a sub process. When I do file open, it starts trame with the appropriate file. When I open a new file, it sh…

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## [Unable to build docker image because of vtk](https://discourse.vtk.org/t/unable-to-build-docker-image-because-of-vtk/16085)

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**Author:** [@teflon](https://discourse.vtk.org/u/teflon)\
**Replies:** 1\
**Last updated:** [October 8, 2025, 6:07am UTC](https://discourse.vtk.org/t/unable-to-build-docker-image-because-of-vtk/16085 "2025-10-08T06:07:51Z")

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Hey all, I have a poetry project which needs a library called pyoma-2 (^1.2.0). This package uses vtk. My docker image does not build because of this error I get: 138.0 Unable to find installation candidates for vtk …

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## [vtk 9.5 q: what is proper way to create Python vtkDataSet object from C++ address](https://discourse.vtk.org/t/vtk-9-5-q-what-is-proper-way-to-create-python-vtkdataset-object-from-c-address/15712)

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**Author:** [@cyrush](https://discourse.vtk.org/u/cyrush)\
**Replies:** 4\
**Last updated:** [October 7, 2025, 3:49pm UTC](https://discourse.vtk.org/t/vtk-9-5-q-what-is-proper-way-to-create-python-vtkdataset-object-from-c-address/15712 "2025-10-07T15:49:02Z")

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To wrap a C++ object with a known address into python, in the past, we have used something like the following: vtkobj = vtk.vtkDataSet('01e3456') The string arg holds the hex address of an existing C++ vtkDataSet poin…

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## [Using vtkOrientationMarkerWidget with vtkMFCWindow](https://discourse.vtk.org/t/using-vtkorientationmarkerwidget-with-vtkmfcwindow/16081)

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**Author:** [@Kenneth\_Sutherland](https://discourse.vtk.org/u/Kenneth_Sutherland)\
**Replies:** 1\
**Last updated:** [October 7, 2025, 11:46am UTC](https://discourse.vtk.org/t/using-vtkorientationmarkerwidget-with-vtkmfcwindow/16081 "2025-10-07T11:46:23Z")

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I have developed a Windows app based on vtkMFCWindow. Now I would like to add a vtkAxesActor so I can indicate the x, y and z axes. It seems that vtkAxesActor requires vtkOrientationMarkerWidget. However, when I added th…

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## [vtkTriangleFilter leads to hole in mesh](https://discourse.vtk.org/t/vtktrianglefilter-leads-to-hole-in-mesh/16071)

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**Author:** [@citronella3alain](https://discourse.vtk.org/u/citronella3alain)\
**Replies:** 2\
**Last updated:** [October 2, 2025, 12:47am UTC](https://discourse.vtk.org/t/vtktrianglefilter-leads-to-hole-in-mesh/16071 "2025-10-02T00:47:12Z")

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I have a polydata that is comprised of quads. When I triangulate it, the mesh has a hole. Why? In the screenshot below, left is the original polydata, right is post triangulation. For comparison, when I tetrahedrali…

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## [vtkCellArray containing pointers to other vtkCellArrays](https://discourse.vtk.org/t/vtkcellarray-containing-pointers-to-other-vtkcellarrays/9829)

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**Author:** [@CsatiZoltan](https://discourse.vtk.org/u/CsatiZoltan)\
**Replies:** 13\
**Last updated:** [September 29, 2025, 9:06am UTC](https://discourse.vtk.org/t/vtkcellarray-containing-pointers-to-other-vtkcellarrays/9829 "2025-09-29T09:06:37Z")

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The mesh data structure at hand comes from a simulation framework, and is large. To avoid creating a copy, I populate a vtkCellArray object using the SetData method pass this object to a vtkUnstructuredGrid object usin…

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## [How to determine/account for vertex coordinates that are normalized before being passed to the vertex shader?](https://discourse.vtk.org/t/how-to-determine-account-for-vertex-coordinates-that-are-normalized-before-being-passed-to-the-vertex-shader/16061)

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**Author:** [@scotsman60](https://discourse.vtk.org/u/scotsman60)\
**Replies:** 1\
**Last updated:** [September 24, 2025, 9:21pm UTC](https://discourse.vtk.org/t/how-to-determine-account-for-vertex-coordinates-that-are-normalized-before-being-passed-to-the-vertex-shader/16061 "2025-09-24T21:21:38Z")

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Hello!!! I’m using VTK 9.5.0 and trying to modify the position of points in the glsl vertex shader. I’ve noticed that in some cases (not all), the vertex locations passed to the vertex shader by VTK are scaled/shifted …

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## [View manipulation in a native VTK window is slower than Paraview](https://discourse.vtk.org/t/view-manipulation-in-a-native-vtk-window-is-slower-than-paraview/16056)

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**Author:** [@scotsman60](https://discourse.vtk.org/u/scotsman60)\
**Replies:** 3\
**Last updated:** [September 24, 2025, 3:42pm UTC](https://discourse.vtk.org/t/view-manipulation-in-a-native-vtk-window-is-slower-than-paraview/16056 "2025-09-24T15:42:03Z")

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Hello!!! I’m using VTK 9.5 and Paraview on Windows 11 I have noticed that manipulating the view of an object (Zoom, Pan, Rotate) in a native VTKRenderWindow on Windows is considerably slower than doing the same operati…

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## [Incorrect viewport is zoomed with trame.widgets.vtklocal.LocalView](https://discourse.vtk.org/t/incorrect-viewport-is-zoomed-with-trame-widgets-vtklocal-localview/16035)

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**Author:** [@senanokah](https://discourse.vtk.org/u/senanokah)\
**Replies:** 4\
**Last updated:** [September 19, 2025, 11:45am UTC](https://discourse.vtk.org/t/incorrect-viewport-is-zoomed-with-trame-widgets-vtklocal-localview/16035 "2025-09-19T11:45:44Z")

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Hi! First of all, thank you so much for your work on Trame/VTK/WASM. I’ve got an issue where zooming while hovering the cursor over different render viewports always zoomes the first renderer. I’m using the LocalView f…

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## [Building vtkbool as a remote module does not seem to complete.](https://discourse.vtk.org/t/building-vtkbool-as-a-remote-module-does-not-seem-to-complete/16043)

<div class="topic-metadata">

**Author:** [@chir-set](https://discourse.vtk.org/u/chir-set)\
**Replies:** 11\
**Last updated:** [September 17, 2025, 1:30pm UTC](https://discourse.vtk.org/t/building-vtkbool-as-a-remote-module-does-not-seem-to-complete/16043 "2025-09-17T13:30:18Z")

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Hello, I am trying to build vtkbool as a remote module of VTK 9.5 within Slicer’s build tree. This vkbool.remote.cmake file is used: # # vtkbool Classes # vtk\_fetch\_module(vtkbool “Boolean operations on polydata” G…

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