# Support

**URL:** https://discourse.vtk.org/c/support/6.md?page=109

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

**Page:** 110

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## [How to set representation from points to surface?](https://discourse.vtk.org/t/how-to-set-representation-from-points-to-surface/5335)

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**Author:** [@vandoitruong1997](https://discourse.vtk.org/u/vandoitruong1997)\
**Replies:** 0\
**Last updated:** [March 6, 2021, 1:42pm UTC](https://discourse.vtk.org/t/how-to-set-representation-from-points-to-surface/5335 "2021-03-06T13:42:07Z")

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Hello everyone, I am a newbie in vtk, I want to create the application with winform to visualize a science data. Specifically, My data is a “.vtk” file format, with uniform structured and scalars data. I already try thi…

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## [Feed the output of a Filter to the same Filter's Input in a Loop](https://discourse.vtk.org/t/feed-the-output-of-a-filter-to-the-same-filters-input-in-a-loop/5310)

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**Author:** [@mallikarjun49](https://discourse.vtk.org/u/mallikarjun49)\
**Replies:** 4\
**Last updated:** [March 5, 2021, 5:46pm UTC](https://discourse.vtk.org/t/feed-the-output-of-a-filter-to-the-same-filters-input-in-a-loop/5310 "2021-03-05T17:46:03Z")

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Hello All, I would like to do boolean operation repeatedly on the output of the boolean filter itself like below. auto boolFilter = vtkSmartPointer\<vtkPolyDataBooleanFilter\>::New(); boolFilter-\>SetOperModeToDifference…

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## [Can the VTK get the world coordinates of the vertices in the read model in the OpenGL shader?](https://discourse.vtk.org/t/can-the-vtk-get-the-world-coordinates-of-the-vertices-in-the-read-model-in-the-opengl-shader/5325)

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**Author:** [@Jone7](https://discourse.vtk.org/u/Jone7)\
**Replies:** 1\
**Last updated:** [March 5, 2021, 4:01pm UTC](https://discourse.vtk.org/t/can-the-vtk-get-the-world-coordinates-of-the-vertices-in-the-read-model-in-the-opengl-shader/5325 "2021-03-05T16:01:21Z")

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I want to use the world coordinates of the model to do the lighting calculation, and I saw in VTK opengl shader can get the model coordinates and view coordinates of vertex, I think that using model matrix multiplicate…

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## [VTK raycasting aliasing lines](https://discourse.vtk.org/t/vtk-raycasting-aliasing-lines/5321)

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**Author:** [@desheng](https://discourse.vtk.org/u/desheng)\
**Replies:** 2\
**Last updated:** [March 5, 2021, 2:35pm UTC](https://discourse.vtk.org/t/vtk-raycasting-aliasing-lines/5321 "2021-03-05T14:35:42Z")

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Tried to generate raycasting for a knee CT, but the resulting image shows some aliasing lines, as shown in the image. Anyone can help me out? Thanks!

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## [Using VTK gradient filter to calculate the divergence of a vector field](https://discourse.vtk.org/t/using-vtk-gradient-filter-to-calculate-the-divergence-of-a-vector-field/5319)

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**Author:** [@Renard](https://discourse.vtk.org/u/Renard)\
**Replies:** 2\
**Last updated:** [March 5, 2021, 9:19am UTC](https://discourse.vtk.org/t/using-vtk-gradient-filter-to-calculate-the-divergence-of-a-vector-field/5319 "2021-03-05T09:19:08Z")

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Hi, I have written a simple code in python to calculate the divergence of a vector field stored in a VTU file. I’m getting the following error, what is going wrong here? TypeError: method requires a string argument imp…

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## [Cylinder Demo bugs in ver 8.2.0 on Fedora 32 with NVidia hardware](https://discourse.vtk.org/t/cylinder-demo-bugs-in-ver-8-2-0-on-fedora-32-with-nvidia-hardware/4310)

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**Author:** [@DavidChipman](https://discourse.vtk.org/u/DavidChipman)\
**Replies:** 11\
**Last updated:** [March 5, 2021, 6:23am UTC](https://discourse.vtk.org/t/cylinder-demo-bugs-in-ver-8-2-0-on-fedora-32-with-nvidia-hardware/4310 "2021-03-05T06:23:18Z")

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I have a problem getting the Cylinder demo program to work properly on Fedora 32, with NVidia drviers. However, to do something similar in ParaView 5.8 works just fine.

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## [Share interactors](https://discourse.vtk.org/t/share-interactors/5324)

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**Author:** [@Jothybasu\_Selvaraj](https://discourse.vtk.org/u/Jothybasu_Selvaraj)\
**Replies:** 1\
**Last updated:** [March 5, 2021, 2:42am UTC](https://discourse.vtk.org/t/share-interactors/5324 "2021-03-05T02:42:44Z")

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Hi all, I am trying to share the same interactor among three renderers. here is the code i tried but it will only apply in to the last renderer. Any hints how to do this properly? vtkSmartPointeriact= vtkSmartPointer:…

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## [How to extract boundary cells from a vtkUnstructuredGrid of solid cells](https://discourse.vtk.org/t/how-to-extract-boundary-cells-from-a-vtkunstructuredgrid-of-solid-cells/5312)

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**Author:** [@scotsman60](https://discourse.vtk.org/u/scotsman60)\
**Replies:** 1\
**Last updated:** [March 4, 2021, 3:54pm UTC](https://discourse.vtk.org/t/how-to-extract-boundary-cells-from-a-vtkunstructuredgrid-of-solid-cells/5312 "2021-03-04T15:54:31Z")

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Hello!!! I am trying to extract all cells that touch the free surface of a solid mesh in a vtkUnstrucuredGrid - basically to ge the first layer of cells on the bondary. I figured I’d get all of the points on the free s…

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## [Object size](https://discourse.vtk.org/t/object-size/5308)

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**Author:** [@mauro](https://discourse.vtk.org/u/mauro)\
**Replies:** 1\
**Last updated:** [March 4, 2021, 9:51am UTC](https://discourse.vtk.org/t/object-size/5308 "2021-03-04T09:51:48Z")

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Dear all, I’m reading a volume from a file (.vtk) using vtkGenericDataObjectReader, in python: reader = vtk.vtkGenericDataObjectReader() reader.SetFileName( "file.vtk" ) It reads the file with no issues. However, I’m …

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## [Absolute Values for Depth Image](https://discourse.vtk.org/t/absolute-values-for-depth-image/326)

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**Author:** [@banesullivan](https://discourse.vtk.org/u/banesullivan)\
**Replies:** 6\
**Last updated:** [March 3, 2021, 8:21pm UTC](https://discourse.vtk.org/t/absolute-values-for-depth-image/326 "2021-03-03T20:21:47Z")

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When using the vtk.vtkWindowToImageFilter to produce a buffered image of the distances to the mesh in the rendering scene, is it possible to use the 0-1 depth ranges to recover the true distances from the camera to the m…

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## [Do clippers in vtk merge or remove duplicate points?](https://discourse.vtk.org/t/do-clippers-in-vtk-merge-or-remove-duplicate-points/5299)

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**Author:** [@Waqas\_Bakht](https://discourse.vtk.org/u/Waqas_Bakht)\
**Replies:** 4\
**Last updated:** [March 3, 2021, 7:33pm UTC](https://discourse.vtk.org/t/do-clippers-in-vtk-merge-or-remove-duplicate-points/5299 "2021-03-03T19:33:51Z")

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Wondering if using any of the vtk clippers (poly data clipper, generic dataset clippers, table based data set clipper) remove or merge duplicate points?

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## [Weird Blurring/Shadowing After Using VtkPolyDataClipper.](https://discourse.vtk.org/t/weird-blurring-shadowing-after-using-vtkpolydataclipper/5223)

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**Author:** [@Waqas\_Bakht](https://discourse.vtk.org/u/Waqas_Bakht)\
**Replies:** 2\
**Last updated:** [March 3, 2021, 6:29pm UTC](https://discourse.vtk.org/t/weird-blurring-shadowing-after-using-vtkpolydataclipper/5223 "2021-03-03T18:29:12Z")

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Hello, I am using the VtkPolyDataClipper to cut some Polydata into a few pieces, however, the Clipped Polydata coloring looks a little weird. The Clipped Polydata should be a smaller section of the original but should h…

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## [Image cursor](https://discourse.vtk.org/t/image-cursor/5295)

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**Author:** [@Jothybasu\_Selvaraj](https://discourse.vtk.org/u/Jothybasu_Selvaraj)\
**Replies:** 4\
**Last updated:** [March 3, 2021, 3:38am UTC](https://discourse.vtk.org/t/image-cursor/5295 "2021-03-03T03:38:42Z")

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Hello, I want to create a cursor like the one shown in the image Which class is this exactly, there are numerous cursors in vtk. BTW, I am not using vtkImaegViewer2D, I have my own renderer and I use vtkImaegReslice. …

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## [Volume Ray Casting Isosurface on CPU](https://discourse.vtk.org/t/volume-ray-casting-isosurface-on-cpu/5294)

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**Author:** [@paulojamorim](https://discourse.vtk.org/u/paulojamorim)\
**Replies:** 1\
**Last updated:** [March 2, 2021, 10:46pm UTC](https://discourse.vtk.org/t/volume-ray-casting-isosurface-on-cpu/5294 "2021-03-02T22:46:37Z")

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Hi Everyone, Is there any way to use volume ray casting isosurface on CPU? Like old vtkVolumeRayCastIsosurfaceFunction. Best regards, Paulo Amorim

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## [Animating glyphs in Blender using BVTKnodes](https://discourse.vtk.org/t/animating-glyphs-in-blender-using-bvtknodes/5298)

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**Author:** [@Suraj\_Vibromech](https://discourse.vtk.org/u/Suraj_Vibromech)\
**Replies:** 0\
**Last updated:** [March 2, 2021, 10:25am UTC](https://discourse.vtk.org/t/animating-glyphs-in-blender-using-bvtknodes/5298 "2021-03-02T10:25:06Z")

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Good Day, I have installed BVTKnodes plugin for Blender and have created the streamlines and sphere glyphs as two separate blender meshes. I am creating these by referencing to the paraview filters. Similar to using the…

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## [Share interactors for window level and width](https://discourse.vtk.org/t/share-interactors-for-window-level-and-width/5296)

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**Author:** [@Jothybasu\_Selvaraj](https://discourse.vtk.org/u/Jothybasu_Selvaraj)\
**Replies:** 0\
**Last updated:** [March 2, 2021, 8:55am UTC](https://discourse.vtk.org/t/share-interactors-for-window-level-and-width/5296 "2021-03-02T08:55:47Z")

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Hello, I have MPR views and like to sync interactors on mouse move to adjust window level/width on all three views while the mouse is moved on any one image. Any idea how to do this? What the pipeline is? I am using v…

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## [Distributed OpenFoam cases cause Segmentation Fault](https://discourse.vtk.org/t/distributed-openfoam-cases-cause-segmentation-fault/5286)

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**Author:** [@Art](https://discourse.vtk.org/u/Art)\
**Replies:** 0\
**Last updated:** [March 1, 2021, 4:44pm UTC](https://discourse.vtk.org/t/distributed-openfoam-cases-cause-segmentation-fault/5286 "2021-03-01T16:44:57Z")

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Dear developers, we have recently moved to a new VTK version, but it causes a segmentation fault if we try opening distributed OpenFOAM cases. We rely on python interface and installed vtk using pip, specifically the 9…

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## [How to fasten VTK addPoint Loop (Python)](https://discourse.vtk.org/t/how-to-fasten-vtk-addpoint-loop-python/5270)

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**Author:** [@Bastian\_Julich](https://discourse.vtk.org/u/Bastian_Julich)\
**Replies:** 2\
**Last updated:** [March 2, 2021, 5:14am UTC](https://discourse.vtk.org/t/how-to-fasten-vtk-addpoint-loop-python/5270 "2021-03-02T05:14:29Z")

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As i am starting to build some basic plotting methods for 3D visualization with VTK for some Data-Visualization, i ran over the following issue: My Dataset is usually about the Size ob 200e6-1000e6 Datapoints (Sensor Va…

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## [vtkWin32OpenGLRenderWindow resize (memory leak)?](https://discourse.vtk.org/t/vtkwin32openglrenderwindow-resize-memory-leak/5176)

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**Author:** [@CharInt0](https://discourse.vtk.org/u/CharInt0)\
**Replies:** 27\
**Last updated:** [March 1, 2021, 9:18pm UTC](https://discourse.vtk.org/t/vtkwin32openglrenderwindow-resize-memory-leak/5176 "2021-03-01T21:18:02Z")

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I am playing with the Win32Cone example because I need to implement a Win32 application: I wanted to add resizing to the window so I simply added in the WndProc function the handling for the WM\_SIZE message: case W…

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## [Getting area visible in viewer](https://discourse.vtk.org/t/getting-area-visible-in-viewer/5064)

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**Author:** [@ljs](https://discourse.vtk.org/u/ljs)\
**Replies:** 2\
**Last updated:** [March 1, 2021, 5:01pm UTC](https://discourse.vtk.org/t/getting-area-visible-in-viewer/5064 "2021-03-01T17:01:05Z")

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Hi, I am working on a viewer for subsurface data (geology). In the app, users can load grids and plot data on the grids. They can zoom in so that only a small part of the grid is visible in the rendering window. I wou…

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## [Prism (defined by 6 planes) volume crop from other volume.](https://discourse.vtk.org/t/prism-defined-by-6-planes-volume-crop-from-other-volume/5280)

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**Author:** [@Luis\_Carlos\_Carneiro](https://discourse.vtk.org/u/Luis_Carlos_Carneiro)\
**Replies:** 6\
**Last updated:** [March 1, 2021, 3:35pm UTC](https://discourse.vtk.org/t/prism-defined-by-6-planes-volume-crop-from-other-volume/5280 "2021-03-01T15:35:20Z")

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Dear All, reader.GetOutputPort() have a .mhd image There are 6 planes which is defined by 3 points in which is get the normal of the plane. I want to remove to a volume, a prism (6 faces) delimited by 6 planes. volu…

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## [Tracking Multiple Actors](https://discourse.vtk.org/t/tracking-multiple-actors/5285)

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**Author:** [@Cliff](https://discourse.vtk.org/u/Cliff)\
**Replies:** 0\
**Last updated:** [March 1, 2021, 4:20pm UTC](https://discourse.vtk.org/t/tracking-multiple-actors/5285 "2021-03-01T16:20:23Z")

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Hi all, For an application I’m building I’d like to be able to track the relative pose and position of two vtkActors, I’me sure somewhere in the code there is the information I need but I can’t seem to find it! To clar…

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## [What is the replacement of the inputport and outputport classes in vtk7.1.1?](https://discourse.vtk.org/t/what-is-the-replacement-of-the-inputport-and-outputport-classes-in-vtk7-1-1/5278)

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**Author:** [@Vettle](https://discourse.vtk.org/u/Vettle)\
**Replies:** 0\
**Last updated:** [March 1, 2021, 10:59am UTC](https://discourse.vtk.org/t/what-is-the-replacement-of-the-inputport-and-outputport-classes-in-vtk7-1-1/5278 "2021-03-01T10:59:39Z")

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## [Using Marching Cube output in IterativeClosestPointTransform](https://discourse.vtk.org/t/using-marching-cube-output-in-iterativeclosestpointtransform/5271)

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**Author:** [@Amin](https://discourse.vtk.org/u/Amin)\
**Replies:** 0\
**Last updated:** [February 27, 2021, 8:00pm UTC](https://discourse.vtk.org/t/using-marching-cube-output-in-iterativeclosestpointtransform/5271 "2021-02-27T20:00:51Z")

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Hi, How can I use the result of the Marching cube class in ICP registration?

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## [Add overlay 3D stl file on 2D image](https://discourse.vtk.org/t/add-overlay-3d-stl-file-on-2d-image/5265)

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**Author:** [@Amir\_Hossein\_Zeydi](https://discourse.vtk.org/u/Amir_Hossein_Zeydi)\
**Replies:** 0\
**Last updated:** [February 26, 2021, 5:41pm UTC](https://discourse.vtk.org/t/add-overlay-3d-stl-file-on-2d-image/5265 "2021-02-26T17:41:04Z")

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I added two actor stl files to an imageviewer but the actors are placed behind the 2D image in every view. Is there a way to put the 3D files in front of the 2D image? here is the code: #First STL file reader =…

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## [ERROR for VTK 9.0.1 vtkContextDevice2D](https://discourse.vtk.org/t/error-for-vtk-9-0-1-vtkcontextdevice2d/5259)

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**Author:** [@xiaocaiji](https://discourse.vtk.org/u/xiaocaiji)\
**Replies:** 1\
**Last updated:** [February 26, 2021, 10:33am UTC](https://discourse.vtk.org/t/error-for-vtk-9-0-1-vtkcontextdevice2d/5259 "2021-02-26T10:33:23Z")

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I build VTK-9.0.1 using CMake 3.19.4. There is the name lists in cmake: Then I successed generating the example CylinderExample but I can’t find vtkContextDevice2D.lib in the folder E:\\codes\\VTK-9.0.1-bin\\lib\\Debug. …

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## [Refined cell in vtkUniformGrid](https://discourse.vtk.org/t/refined-cell-in-vtkuniformgrid/5246)

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**Author:** [@hakostra](https://discourse.vtk.org/u/hakostra)\
**Replies:** 1\
**Last updated:** [February 25, 2021, 10:01pm UTC](https://discourse.vtk.org/t/refined-cell-in-vtkuniformgrid/5246 "2021-02-25T22:01:27Z")

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I create a vtkMultiBlockDataSet consisting of a number of vtkUniformGrid’s. This is the result of an AMR code and I have grids at several levels. I compute the blanking explicitly and use the vtkDataSetAttribute::REFINE…

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## [Extract field data from .vtu file](https://discourse.vtk.org/t/extract-field-data-from-vtu-file/5254)

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**Author:** [@tont\_fe](https://discourse.vtk.org/u/tont_fe)\
**Replies:** 0\
**Last updated:** [February 25, 2021, 10:34am UTC](https://discourse.vtk.org/t/extract-field-data-from-vtu-file/5254 "2021-02-25T10:34:17Z")

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I have a problem trying to extract data from a .vtu file. I have the file and I would like to do some post-processing, in particular I would like to write .npy files for the grid and some variables of interest. I past h…

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## [Continuing processing after interactor (Python)](https://discourse.vtk.org/t/continuing-processing-after-interactor-python/5241)

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**Author:** [@Luis\_Carlos\_Carneiro](https://discourse.vtk.org/u/Luis_Carlos_Carneiro)\
**Replies:** 6\
**Last updated:** [February 24, 2021, 8:10pm UTC](https://discourse.vtk.org/t/continuing-processing-after-interactor-python/5241 "2021-02-24T20:10:12Z")

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Dear All, How to process after interactor.Start()? I want to interact with the displayed image (as the interactor) but I want at the same time to process the gotten pointer position and add other images to the camera i…

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## [Recreate 3D volume rendering from vtk python to vtk.js](https://discourse.vtk.org/t/recreate-3d-volume-rendering-from-vtk-python-to-vtk-js/5248)

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**Author:** [@Saptarshi\_Paul](https://discourse.vtk.org/u/Saptarshi_Paul)\
**Replies:** 5\
**Last updated:** [February 24, 2021, 7:08pm UTC](https://discourse.vtk.org/t/recreate-3d-volume-rendering-from-vtk-python-to-vtk-js/5248 "2021-02-24T19:08:53Z")

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Hello everyone, I was able to render a 3d Volume from 2D png image stack using vtk python. I want to create the same thing with vtk.js. Can anyone please guide me how to do that. I would really appreciate any help. Mos…

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