# Latest

**URL:** https://discourse.vtk.org/latest.md?page=113

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

**Page:** 114

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## [Draggable label over qvtkWidget](https://discourse.vtk.org/t/draggable-label-over-qvtkwidget/9670)

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**Author:** [@Manju](https://discourse.vtk.org/u/Manju)\
**Replies:** 0\
**Last updated:** [October 25, 2022, 5:03am UTC](https://discourse.vtk.org/t/draggable-label-over-qvtkwidget/9670 "2022-10-25T05:03:04Z")

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I am working with Qt creator 7.0.2 with Cpp for developing an application which involves image editing and enhancement. I’m currently using a qvtkWidget to display the image. I need to place a draggable and resizable lab…

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## [Select the invisible points and dye them](https://discourse.vtk.org/t/select-the-invisible-points-and-dye-them/9661)

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**Author:** [@claude](https://discourse.vtk.org/u/claude)\
**Replies:** 2\
**Last updated:** [October 25, 2022, 1:34am UTC](https://discourse.vtk.org/t/select-the-invisible-points-and-dye-them/9661 "2022-10-25T01:34:14Z")

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Hi everyone, I am using vtkSelectVisiblePoints to get invisible points from a vtkPolyData, and i can get the pointsset i want.Now i want to change the color of the original polydata through the output pointsset,what sho…

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## [Visualize the Leaning Tower of Pisa (or San Francisco's Millennium Tower)](https://discourse.vtk.org/t/visualize-the-leaning-tower-of-pisa-or-san-franciscos-millennium-tower/9665)

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**Author:** [@SpareSimian](https://discourse.vtk.org/u/SpareSimian)\
**Replies:** 4\
**Last updated:** [October 24, 2022, 10:45pm UTC](https://discourse.vtk.org/t/visualize-the-leaning-tower-of-pisa-or-san-franciscos-millennium-tower/9665 "2022-10-24T22:45:18Z")

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I’m looking for inspiration on how to present my data. I can do the math part. What I’m looking for is how to present it. Imagine a multistory building of equally-spaced floors, either cylindrical (like a grain silo) or…

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## [More than 250k of labels](https://discourse.vtk.org/t/more-than-250k-of-labels/9664)

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**Author:** [@Mesh](https://discourse.vtk.org/u/Mesh)\
**Replies:** 1\
**Last updated:** [October 24, 2022, 10:43pm UTC](https://discourse.vtk.org/t/more-than-250k-of-labels/9664 "2022-10-24T22:43:41Z")

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Hi, I am using vtkLabelPlacementMapper to display more than 250k of labels, it shows labels but the zoom in and zoom out …ect is to slow. Is there a better solution the improve rendering and interactivity performance? …

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## [Building vtk-9.2.2 with vtkDicom requires running cmake twice](https://discourse.vtk.org/t/building-vtk-9-2-2-with-vtkdicom-requires-running-cmake-twice/9659)

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**Author:** [@Carol\_Capek](https://discourse.vtk.org/u/Carol_Capek)\
**Replies:** 5\
**Last updated:** [October 24, 2022, 6:05pm UTC](https://discourse.vtk.org/t/building-vtk-9-2-2-with-vtkdicom-requires-running-cmake-twice/9659 "2022-10-24T18:05:13Z")

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Hello, I tried to build vtk-9.2.2 the other day and ran into a problem when running: cmake ../ -GNinja -DCMAKE\_INSTALL\_PREFIX=/opt/VTK-9.2.2 -DBUILD\_SHARED\_LIBS=false -DCMAKE\_BUILD\_TYPE=Release -DVTK\_MODULE\_ENABLE\_VTK\_…

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## [Qt6 + VTK9: Objects always rotating](https://discourse.vtk.org/t/qt6-vtk9-objects-always-rotating/9658)

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**Author:** [@andrsd](https://discourse.vtk.org/u/andrsd)\
**Replies:** 1\
**Last updated:** [October 24, 2022, 3:41pm UTC](https://discourse.vtk.org/t/qt6-vtk9-objects-always-rotating/9658 "2022-10-24T15:41:45Z")

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When I build the minimal Qt VTK app example\[1\] with Qt 6.2.4 and VTK 9.2.2, the displayed object rotates such that it follows the mouse cursor. If I build just a standalone VTK app (like BorderWidgetQt \[2\]) I get the ex…

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## [apply marching cube on unstructured grid with vtk voxel cells](https://discourse.vtk.org/t/apply-marching-cube-on-unstructured-grid-with-vtk-voxel-cells/9593)

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**Author:** [@willk](https://discourse.vtk.org/u/willk)\
**Replies:** 10\
**Last updated:** [October 24, 2022, 2:45pm UTC](https://discourse.vtk.org/t/apply-marching-cube-on-unstructured-grid-with-vtk-voxel-cells/9593 "2022-10-24T14:45:03Z")

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I am trying to use a vtkMarchingCubes algo on a Unstructuredgrid data. The problem i am facing is vtkMarchingCubes only work with vtkImageData. ERROR:root:Input for connection index 0 on input port index 0 for algorithm…

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## [Including VTK9 built from source in a wider project](https://discourse.vtk.org/t/including-vtk9-built-from-source-in-a-wider-project/9612)

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**Author:** [@thomas-wright](https://discourse.vtk.org/u/thomas-wright)\
**Replies:** 5\
**Last updated:** [October 24, 2022, 2:23am UTC](https://discourse.vtk.org/t/including-vtk9-built-from-source-in-a-wider-project/9612 "2022-10-24T02:23:56Z")

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Due to constraints around our build process, I would like to include the VTK source code alongside our own, for our application build configured with cmake. With VTK8 and earlier, we have been using the cmake command ADD…

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## [Hoe can I get coordinates of vtkAxesActor after transform?](https://discourse.vtk.org/t/hoe-can-i-get-coordinates-of-vtkaxesactor-after-transform/9657)

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**Author:** [@Danyuhui](https://discourse.vtk.org/u/Danyuhui)\
**Replies:** 1\
**Last updated:** [October 23, 2022, 9:39pm UTC](https://discourse.vtk.org/t/hoe-can-i-get-coordinates-of-vtkaxesactor-after-transform/9657 "2022-10-23T21:39:37Z")

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Hi VTK experts I’m trying to create a vtkAxesActor(axes) and transform it by rotating.I wonder if there’s any functions can help me find out the coordinates of the X/Y/Z axis after transforming. I’ve tried to uses math…

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## [Average Mesh and mesh scalar operations](https://discourse.vtk.org/t/average-mesh-and-mesh-scalar-operations/9649)

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**Author:** [@Connor.Bowley](https://discourse.vtk.org/u/Connor.Bowley)\
**Replies:** 5\
**Last updated:** [October 21, 2022, 7:35pm UTC](https://discourse.vtk.org/t/average-mesh-and-mesh-scalar-operations/9649 "2022-10-21T19:35:15Z")

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Are there any vtk filters that support the following operations, and if there is not, would anyone be opposed to the addition of said filters into VTK? Given a set of meshes in point correspondence: Compute the averag…

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## [\[wslink + VTK\] What is the best to receive a stream of events from client](https://discourse.vtk.org/t/wslink-vtk-what-is-the-best-to-receive-a-stream-of-events-from-client/9461)

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**Author:** [@joaomlap](https://discourse.vtk.org/u/joaomlap)\
**Replies:** 4\
**Last updated:** [October 21, 2022, 4:55pm UTC](https://discourse.vtk.org/t/wslink-vtk-what-is-the-best-to-receive-a-stream-of-events-from-client/9461 "2022-10-21T16:55:28Z")

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Hi, I have a server where wslink is the bridge to a VTK.js client. Both are running locally on my machine. On the frontend there is a slider that on change is calling a exportRpc('slider.change') on the server which in…

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## [Error with StyleInteractor](https://discourse.vtk.org/t/error-with-styleinteractor/9640)

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**Author:** [@llobera](https://discourse.vtk.org/u/llobera)\
**Replies:** 3\
**Last updated:** [October 21, 2022, 1:20pm UTC](https://discourse.vtk.org/t/error-with-styleinteractor/9640 "2022-10-21T13:20:13Z")

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I have the following code class MyInteractorStyle(vtkInteractorStyleTerrain): def \_\_init\_\_(self, renderer): self.SetCurrentRenderer(renderer) self.AddObserver("MouseMoveEvent", self.mou…

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## [Example of how to generate a InteractorStyle where mouse click \*\*and\*\* mouse horizontal movement are combined](https://discourse.vtk.org/t/example-of-how-to-generate-a-interactorstyle-where-mouse-click-and-mouse-horizontal-movement-are-combined/9632)

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**Author:** [@llobera](https://discourse.vtk.org/u/llobera)\
**Replies:** 1\
**Last updated:** [October 21, 2022, 8:19am UTC](https://discourse.vtk.org/t/example-of-how-to-generate-a-interactorstyle-where-mouse-click-and-mouse-horizontal-movement-are-combined/9632 "2022-10-21T08:19:25Z")

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I am trying to create my own interactorStyle and I need to be able to change the camera pitch by clicking on the left mouse button while moving the mouse horizontally. Can anyone indicate how to achieve this or point tow…

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## [vtkCompositePolyDataMapper2 with very large numbers of blocks slow](https://discourse.vtk.org/t/vtkcompositepolydatamapper2-with-very-large-numbers-of-blocks-slow/9631)

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**Author:** [@bheld](https://discourse.vtk.org/u/bheld)\
**Replies:** 8\
**Last updated:** [October 21, 2022, 4:15am UTC](https://discourse.vtk.org/t/vtkcompositepolydatamapper2-with-very-large-numbers-of-blocks-slow/9631 "2022-10-21T04:15:53Z")

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We have some cases that will have \> 50,000 blocks in the input to vtkCompositePolyDataMapper2. Should we expect to see inefficiencies in rendering speed in particular (e.g. camera rotation)? We could modify the code th…

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## [Opacity issue in QVTKOpenGLWidget and PCL Visualizer](https://discourse.vtk.org/t/opacity-issue-in-qvtkopenglwidget-and-pcl-visualizer/9646)

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**Author:** [@Panda12197](https://discourse.vtk.org/u/Panda12197)\
**Replies:** 1\
**Last updated:** [October 21, 2022, 2:53am UTC](https://discourse.vtk.org/t/opacity-issue-in-qvtkopenglwidget-and-pcl-visualizer/9646 "2022-10-21T02:53:23Z")

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I am trying to set the opacity for Cube in pclviewer with surface. It is successed but I can not set the opacity value. It is OK when the opacity value is 1.0 but any values less than 1.0 make it invisible. The program…

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## [Cleanup warnings in current vtk 9 plans?](https://discourse.vtk.org/t/cleanup-warnings-in-current-vtk-9-plans/9586)

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**Author:** [@fab672000](https://discourse.vtk.org/u/fab672000)\
**Replies:** 19\
**Last updated:** [October 20, 2022, 4:04pm UTC](https://discourse.vtk.org/t/cleanup-warnings-in-current-vtk-9-plans/9586 "2022-10-20T16:04:40Z")

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Hi, so I am currently building vtk 9.2 from sources and noted a lot of warnings (\>1000 warnings in release mode when building with vs2022 !) during the build are happening, most often due to unferenced formal parameters…

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## [How to generate a triangulation with the correct orientation?](https://discourse.vtk.org/t/how-to-generate-a-triangulation-with-the-correct-orientation/9599)

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**Author:** [@llobera](https://discourse.vtk.org/u/llobera)\
**Replies:** 1\
**Last updated:** [October 20, 2022, 2:32pm UTC](https://discourse.vtk.org/t/how-to-generate-a-triangulation-with-the-correct-orientation/9599 "2022-10-20T14:32:20Z")

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I have the following code (see below) where: l,r,t,b are the coordinate bounds of a numpy array Z of size nrows x ncols that contains elevation data x =np.linspace(l, r, ncols) y =np.linspace(t, b, nrows) X,Y = np.mes…

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## [How to identify and return a specific actor within a collection of actors?](https://discourse.vtk.org/t/how-to-identify-and-return-a-specific-actor-within-a-collection-of-actors/9653)

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**Author:** [@llobera](https://discourse.vtk.org/u/llobera)\
**Replies:** 0\
**Last updated:** [October 20, 2022, 10:57am UTC](https://discourse.vtk.org/t/how-to-identify-and-return-a-specific-actor-within-a-collection-of-actors/9653 "2022-10-20T10:57:34Z")

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I have two related questions: Is there a way to provide a unique identifier to a vtkActor() ? Using renderer.GetActors() I get back a collection of actors, I am looking for a specific actor. How can I find and return …

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## [How to add attributes in Shader？](https://discourse.vtk.org/t/how-to-add-attributes-in-shader/9610)

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**Author:** [@sunlin0oo](https://discourse.vtk.org/u/sunlin0oo)\
**Replies:** 7\
**Last updated:** [October 20, 2022, 10:06am UTC](https://discourse.vtk.org/t/how-to-add-attributes-in-shader/9610 "2022-10-20T10:06:48Z")

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For example in vtkPolyDataVS.glsl attribute vec4 vertexMC; I want to add another attribute like vertexMC; These operations need to be placed in the shader. I now call back the code data based on the PloydataMapper-Ca…

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## [Convert 2d polydata data(2d mesh) to 3d mesh with cell data](https://discourse.vtk.org/t/convert-2d-polydata-data-2d-mesh-to-3d-mesh-with-cell-data/9645)

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**Author:** [@lizemin2016](https://discourse.vtk.org/u/lizemin2016)\
**Replies:** 2\
**Last updated:** [October 20, 2022, 3:08am UTC](https://discourse.vtk.org/t/convert-2d-polydata-data-2d-mesh-to-3d-mesh-with-cell-data/9645 "2022-10-20T03:08:23Z")

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I have a polydata created by points(with z-value 0) and polys, and cell attribute data, How can I convert this 2d polydata data(2d mesh) to 3d mesh use the scalar attribute data. I hope you can give me some suggestions a…

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## [BillboardTextActor3D (or similar) for Python](https://discourse.vtk.org/t/billboardtextactor3d-or-similar-for-python/9630)

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**Author:** [@Kevin\_Sweeney](https://discourse.vtk.org/u/Kevin_Sweeney)\
**Replies:** 1\
**Last updated:** [October 19, 2022, 5:55am UTC](https://discourse.vtk.org/t/billboardtextactor3d-or-similar-for-python/9630 "2022-10-19T05:55:18Z")

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I am working in Python (vtk with ipywidgets) and want to annotate my 3D glyphs with information (i.e. data point number etc) I see there is something available in C++ but I cannot find a method to perform the same in Py…

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## [Place object in DICOM patient coordinates](https://discourse.vtk.org/t/place-object-in-dicom-patient-coordinates/9608)

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**Author:** [@mortifiedpenguin](https://discourse.vtk.org/u/mortifiedpenguin)\
**Replies:** 3\
**Last updated:** [October 19, 2022, 7:28pm UTC](https://discourse.vtk.org/t/place-object-in-dicom-patient-coordinates/9608 "2022-10-19T19:28:17Z")

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I am visualizing a DICOM CT dataset using vtk / Activiz. Now I want to place objects (e.g. a sphere for testing) using the DICOM coordinate space as defined by Image Position Patient / Image Orientation Patient. To this …

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## [vtkPolyDataToImageStencil parallelization](https://discourse.vtk.org/t/vtkpolydatatoimagestencil-parallelization/9625)

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**Author:** [@chrisadamsonmcri](https://discourse.vtk.org/u/chrisadamsonmcri)\
**Replies:** 6\
**Last updated:** [October 19, 2022, 2:24am UTC](https://discourse.vtk.org/t/vtkpolydatatoimagestencil-parallelization/9625 "2022-10-19T02:24:37Z")

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vtkPolyDataToImageStencil processes each slice of an image in serial and is slow when executed many times. There is a TODO: in the RequestData indicating that it would be easy to parallelize the method by processing each…

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## [CMake FetchContent() build misses vtkCommonDataModelModule.h](https://discourse.vtk.org/t/cmake-fetchcontent-build-misses-vtkcommondatamodelmodule-h/9618)

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**Author:** [@drpeterfranz](https://discourse.vtk.org/u/drpeterfranz)\
**Replies:** 14\
**Last updated:** [October 18, 2022, 9:56pm UTC](https://discourse.vtk.org/t/cmake-fetchcontent-build-misses-vtkcommondatamodelmodule-h/9618 "2022-10-18T21:56:47Z")

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I am trying to change my build system to use CMake’s FetchContent(...) method. I specify the git repository and a git tag. When I start compiling I get the following: D:\\temp\\buildme2\\vtk-fss\_deps\\vtkrepo-src\\Common\\C…

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## [cellLocator fails to find the points on the boundry](https://discourse.vtk.org/t/celllocator-fails-to-find-the-points-on-the-boundry/9628)

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**Author:** [@1116](https://discourse.vtk.org/u/1116)\
**Replies:** 5\
**Last updated:** [October 18, 2022, 8:37pm UTC](https://discourse.vtk.org/t/celllocator-fails-to-find-the-points-on-the-boundry/9628 "2022-10-18T20:37:04Z")

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Hello, guys: I have an image data shown in figure 1, and I try to use the points in this image data to do the interpolation for the the mesh in figure 2, which is an unstructured data. I try to go through each po…

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## [Non-orthogonal volume rendering from structured points](https://discourse.vtk.org/t/non-orthogonal-volume-rendering-from-structured-points/9641)

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**Author:** [@Gunjan\_Auti](https://discourse.vtk.org/u/Gunjan_Auti)\
**Replies:** 0\
**Last updated:** [October 18, 2022, 8:27pm UTC](https://discourse.vtk.org/t/non-orthogonal-volume-rendering-from-structured-points/9641 "2022-10-18T20:27:03Z")

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Hello all, I have a legacy .vtk file with STRUCTURED\_POINTS in scalar format but the volume I want to render is not parallel to the global coordinate system. Can anyone tell me how can I convert this data to a STRUCTURE…

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## [duplicate mouse events with multiple viewports are used on one render window](https://discourse.vtk.org/t/duplicate-mouse-events-with-multiple-viewports-are-used-on-one-render-window/9638)

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**Author:** [@JohnSkinner](https://discourse.vtk.org/u/JohnSkinner)\
**Replies:** 2\
**Last updated:** [October 18, 2022, 5:57pm UTC](https://discourse.vtk.org/t/duplicate-mouse-events-with-multiple-viewports-are-used-on-one-render-window/9638 "2022-10-18T17:57:14Z")

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I’m creating 4 renderers under one render window. My new interactor style appears to get called 4 times with the same mouse down/move/release events. My desire is to process one mouse event that is under the one render…

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## [Trying to find points that intersect a plane Python](https://discourse.vtk.org/t/trying-to-find-points-that-intersect-a-plane-python/9635)

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**Author:** [@jamesIlosta](https://discourse.vtk.org/u/jamesIlosta)\
**Replies:** 1\
**Last updated:** [October 18, 2022, 3:56pm UTC](https://discourse.vtk.org/t/trying-to-find-points-that-intersect-a-plane-python/9635 "2022-10-18T15:56:10Z")

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Hi, I have an .obj file and I’m trying to find points on the file that intersect a given plane. I did try to use vtkIntersectionPolyDataFilter. I did this by trying to create a plane using import object reader = vtk.v…

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## [Trame: visual analytics everywhere](https://discourse.vtk.org/t/trame-visual-analytics-everywhere/9441)

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**Author:** [@will.schroeder](https://discourse.vtk.org/u/will.schroeder)\
**Replies:** 2\
**Last updated:** [October 18, 2022, 3:00pm UTC](https://discourse.vtk.org/t/trame-visual-analytics-everywhere/9441 "2022-10-18T15:00:33Z")

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Some of you may be interested in trame, a Python framework for creating powerful visual analytics applications that run on common platforms including the web browser. This blog post explains more, we’ll be dropping sever…

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## [About installing VTK in Windows](https://discourse.vtk.org/t/about-installing-vtk-in-windows/9554)

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**Author:** [@vromero59](https://discourse.vtk.org/u/vromero59)\
**Replies:** 3\
**Last updated:** [October 17, 2022, 7:34pm UTC](https://discourse.vtk.org/t/about-installing-vtk-in-windows/9554 "2022-10-17T19:34:47Z")

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I am using Visual Studio 2019 to compile VTK. When I compile INSTALL, I got the messake MSB3073. How I can correct this error?

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