# Latest

**URL:** https://discourse.vtk.org/latest.md?page=242

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

**Page:** 243

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## [ColoredElevationMap speed](https://discourse.vtk.org/t/coloredelevationmap-speed/1279)

<div class="topic-metadata">

**Author:** [@silajim](https://discourse.vtk.org/u/silajim)\
**Replies:** 6\
**Last updated:** [July 29, 2019, 12:57pm UTC](https://discourse.vtk.org/t/coloredelevationmap-speed/1279 "2019-07-29T12:57:29Z")

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Hi, I’ve been searching the interwebs for the past days (3-4) but I cannot find a solution to my problem. I want to color a pointcloud of about 40 million points by height, I took a look into the ColoredElevationMap ex…

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## [compress model with texture](https://discourse.vtk.org/t/compress-model-with-texture/1434)

<div class="topic-metadata">

**Author:** [@xuexl](https://discourse.vtk.org/u/xuexl)\
**Replies:** 0\
**Last updated:** [July 29, 2019, 12:52am UTC](https://discourse.vtk.org/t/compress-model-with-texture/1434 "2019-07-29T00:52:38Z")

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we have a model with texture of a building, but it is so big, so we want to compress it, then view in the web page or for LOD. i find vtkQuadricDecimation can compress mesh, but no texture, we nedd mesh with texture,…

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## [vtk.js mapper for polydata](https://discourse.vtk.org/t/vtk-js-mapper-for-polydata/1430)

<div class="topic-metadata">

**Author:** [@haehn](https://discourse.vtk.org/u/haehn)\
**Replies:** 2\
**Last updated:** [July 28, 2019, 1:10am UTC](https://discourse.vtk.org/t/vtk-js-mapper-for-polydata/1430 "2019-07-28T01:10:53Z")

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Hello! I am trying to map colors based on scalars of a polydata using vtk.js - but I can’t get it to work. polydata = reader.getOutputData(); arrayName = polydata.getPointData().getArrayNam…

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## [Transformation and Position of Two Actors](https://discourse.vtk.org/t/transformation-and-position-of-two-actors/1417)

<div class="topic-metadata">

**Author:** [@at123](https://discourse.vtk.org/u/at123)\
**Replies:** 2\
**Last updated:** [July 26, 2019, 11:21am UTC](https://discourse.vtk.org/t/transformation-and-position-of-two-actors/1417 "2019-07-26T11:21:54Z")

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Hello, I have an actor and it has been transformed in 3D space. It has been rotated and translated. It is somewhere in 3D space. I have a second actor and I want it to be in the same position and orientation as the firs…

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## [PropPicker does not work for ViewProps anymore](https://discourse.vtk.org/t/proppicker-does-not-work-for-viewprops-anymore/1413)

<div class="topic-metadata">

**Author:** [@cvandijck](https://discourse.vtk.org/u/cvandijck)\
**Replies:** 2\
**Last updated:** [July 26, 2019, 9:10am UTC](https://discourse.vtk.org/t/proppicker-does-not-work-for-viewprops-anymore/1413 "2019-07-26T09:10:16Z")

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Hi, In VTK 8.2, the PropPicker, which uses the renderers pick method, changed to use the hardware selector. It seems this selector does not work for general Props like an ImageActor. This means that the general PropPick…

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## [matlab martix to vtkMatrix4x4](https://discourse.vtk.org/t/matlab-martix-to-vtkmatrix4x4/1419)

<div class="topic-metadata">

**Author:** [@at123](https://discourse.vtk.org/u/at123)\
**Replies:** 5\
**Last updated:** [July 25, 2019, 6:16pm UTC](https://discourse.vtk.org/t/matlab-martix-to-vtkmatrix4x4/1419 "2019-07-25T18:16:13Z")

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Hello, I have an existing matlab.double(\[1, 0, 0, 0\], \[0, 1, 0, 0\], \[0, 0, 1, 0\], \[0, 0, 0, 1\]) matlab matrix. I would like to turn it into a vtkMatrix4x4 so I can use it as an argument in PokeMatrix to transform a seco…

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## [Update a custom uniform in a modified shader](https://discourse.vtk.org/t/update-a-custom-uniform-in-a-modified-shader/1366)

<div class="topic-metadata">

**Author:** [@Jellby](https://discourse.vtk.org/u/Jellby)\
**Replies:** 5\
**Last updated:** [July 25, 2019, 5:25pm UTC](https://discourse.vtk.org/t/update-a-custom-uniform-in-a-modified-shader/1366 "2019-07-25T17:25:16Z")

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I have modified the default vtkOpenGLPolyDataMapper along the lines of https://github.com/dmreagan/vtk-shaders (case 1). I have also added a new uniform, which I can set as it is done for diffuseColor in https://github.c…

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## [In OSX vtk window does not get the focus - continued](https://discourse.vtk.org/t/in-osx-vtk-window-does-not-get-the-focus-continued/1418)

<div class="topic-metadata">

**Author:** [@normanius](https://discourse.vtk.org/u/normanius)\
**Replies:** 0\
**Last updated:** [July 25, 2019, 2:23pm UTC](https://discourse.vtk.org/t/in-osx-vtk-window-does-not-get-the-focus-continued/1418 "2019-07-25T14:23:31Z")

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After the nabble mailing list has been shut down, I’d like to continue the discussion about the window-to-front issue on MacOS here on discourse… Preceding discussion: http://vtk.1045678.n5.nabble.com/In-OSX-vtk-window-…

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## [vtkStaticCellLinks, vtkStaticPointLocator, vtkStaticCellLocator - speed improvements](https://discourse.vtk.org/t/vtkstaticcelllinks-vtkstaticpointlocator-vtkstaticcelllocator-speed-improvements/1333)

<div class="topic-metadata">

**Author:** [@will.schroeder](https://discourse.vtk.org/u/will.schroeder)\
**Replies:** 11\
**Last updated:** [July 24, 2019, 4:12pm UTC](https://discourse.vtk.org/t/vtkstaticcelllinks-vtkstaticpointlocator-vtkstaticcelllocator-speed-improvements/1333 "2019-07-24T16:12:40Z")

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Background: Over the past few years there have been substantial speed improvements due to the addition of systems like vtk-m and vtkSMPTools. Additionally, C++11 constructs like std::atomic provide facilities for multith…

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## [how to make unstructured Grid](https://discourse.vtk.org/t/how-to-make-unstructured-grid/1412)

<div class="topic-metadata">

**Author:** [@Vaya\_Putra](https://discourse.vtk.org/u/Vaya_Putra)\
**Replies:** 0\
**Last updated:** [July 24, 2019, 2:59pm UTC](https://discourse.vtk.org/t/how-to-make-unstructured-grid/1412 "2019-07-24T14:59:34Z")

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hello for my practice i already done by manually make unstructured grid 5x5x1 i define coordinate node, connectivity, etc for small grid is done but my problem is how to make grid 100x100x4 i used VTK for better vis…

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## [About gitlab mail notifications](https://discourse.vtk.org/t/about-gitlab-mail-notifications/1406)

<div class="topic-metadata">

**Author:** [@mwestphal](https://discourse.vtk.org/u/mwestphal)\
**Replies:** 3\
**Last updated:** [July 24, 2019, 1:48pm UTC](https://discourse.vtk.org/t/about-gitlab-mail-notifications/1406 "2019-07-24T13:48:03Z")

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Recently, gitlab started to send mail with different subject titles: Re: VTK | VTK | Add vtkGLTFMapper (!5735) Re: VTK | Add vtkGLTFMapper (!5735) Not really practical to manage the mails. Any idea what is going on ?

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## [AffineWidget rotation interaction non-functional?](https://discourse.vtk.org/t/affinewidget-rotation-interaction-non-functional/1404)

<div class="topic-metadata">

**Author:** [@rdbrn](https://discourse.vtk.org/u/rdbrn)\
**Replies:** 0\
**Last updated:** [July 24, 2019, 7:12am UTC](https://discourse.vtk.org/t/affinewidget-rotation-interaction-non-functional/1404 "2019-07-24T07:12:28Z")

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I want to use an AffineWidget to let the user shift and rotate an actor. The shift (translation) part works fine. However the rotation part of the widget seems to be broken? There is a circle drawn but it does not mo…

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## [How to convert the coordinate between pixel and physical (vtkImageReslice)?](https://discourse.vtk.org/t/how-to-convert-the-coordinate-between-pixel-and-physical-vtkimagereslice/1391)

<div class="topic-metadata">

**Author:** [@zhang-qiang-github](https://discourse.vtk.org/u/zhang-qiang-github)\
**Replies:** 4\
**Last updated:** [July 24, 2019, 2:43am UTC](https://discourse.vtk.org/t/how-to-convert-the-coordinate-between-pixel-and-physical-vtkimagereslice/1391 "2019-07-24T02:43:14Z")

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I reslice a 2D image from a 3D volume image by vtkImageReslice. Then, I convert the image (matrix， numpy) from vtkImageReslice.GetOutput(). My question is: for one pixel (x, y) in image, what’s the coordinate in 3D volum…

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## [Preservation of cut plane(vtkImplicitPlaneWidget2)](https://discourse.vtk.org/t/preservation-of-cut-plane-vtkimplicitplanewidget2/1394)

<div class="topic-metadata">

**Author:** [@1111](https://discourse.vtk.org/u/1111)\
**Replies:** 6\
**Last updated:** [July 23, 2019, 1:27am UTC](https://discourse.vtk.org/t/preservation-of-cut-plane-vtkimplicitplanewidget2/1394 "2019-07-23T01:27:21Z")

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Hi, I am improving tkImplicitPlaneWidget2. For example, I want to be able to save to my file by pressing a specific key after selecting the cutting plane. Is it technically possible to save the cutting plane as a 2D i…

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## [dotted line example does not work](https://discourse.vtk.org/t/dotted-line-example-does-not-work/1397)

<div class="topic-metadata">

**Author:** [@marcomusy](https://discourse.vtk.org/u/marcomusy)\
**Replies:** 2\
**Last updated:** [July 22, 2019, 1:01pm UTC](https://discourse.vtk.org/t/dotted-line-example-does-not-work/1397 "2019-07-22T13:01:49Z")

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Hi This example doesn’t seem to work anymore… https://vtk.org/Wiki/VTK/Examples/Python/DottedLine has something changed?

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## [3D rendering for polydata points](https://discourse.vtk.org/t/3d-rendering-for-polydata-points/1365)

<div class="topic-metadata">

**Author:** [@vasya\_slot](https://discourse.vtk.org/u/vasya_slot)\
**Replies:** 1\
**Last updated:** [July 21, 2019, 9:35pm UTC](https://discourse.vtk.org/t/3d-rendering-for-polydata-points/1365 "2019-07-21T21:35:33Z")

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I am a VTK beginner. I have a large number of points with some attribute value for each point. I want to build a 3D volume in VTK / Paraview with the ability to apply various filters. I tried to use Delaunau3D in Paravi…

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## [how to save the result of vtkCutter as opencv::Mat](https://discourse.vtk.org/t/how-to-save-the-result-of-vtkcutter-as-opencv-mat/1393)

<div class="topic-metadata">

**Author:** [@wangfeng](https://discourse.vtk.org/u/wangfeng)\
**Replies:** 1\
**Last updated:** [July 21, 2019, 1:45pm UTC](https://discourse.vtk.org/t/how-to-save-the-result-of-vtkcutter-as-opencv-mat/1393 "2019-07-21T13:45:50Z")

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Hi, good evening. I got the the result of vtkCutter, and rendered it very well.Next, I want to save the result of vtkCutter as opencv::Mat. but I can not get scalarPointer of the image . What should I do, help me please …

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## [Visualization of cutting plane angle (vtkImplicitPlaneWidget2)](https://discourse.vtk.org/t/visualization-of-cutting-plane-angle-vtkimplicitplanewidget2/1372)

<div class="topic-metadata">

**Author:** [@1111](https://discourse.vtk.org/u/1111)\
**Replies:** 2\
**Last updated:** [July 19, 2019, 8:31am UTC](https://discourse.vtk.org/t/visualization-of-cutting-plane-angle-vtkimplicitplanewidget2/1372 "2019-07-19T08:31:25Z")

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Hi, I am using vtkImplicitPlaneWidget2. I want to know the angle and coordinates of the cutting plane after mouse operation. How can I know the angles and coordinates? Please let me know if you know. @dgobbi

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## [Cant read a special type of DICOM by VTK](https://discourse.vtk.org/t/cant-read-a-special-type-of-dicom-by-vtk/1367)

<div class="topic-metadata">

**Author:** [@aneeshikmat](https://discourse.vtk.org/u/aneeshikmat)\
**Replies:** 6\
**Last updated:** [July 19, 2019, 4:35am UTC](https://discourse.vtk.org/t/cant-read-a-special-type-of-dicom-by-vtk/1367 "2019-07-19T04:35:20Z")

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I write code using VTK (c++) which its can read dicom file, and its work prefect and tested for CT, and MRI…but I got error when I try to view dicom file which its an Video, and in normal viewer in VTK return Segmenta…

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## [Building VTK with CMake 3.15](https://discourse.vtk.org/t/building-vtk-with-cmake-3-15/1370)

<div class="topic-metadata">

**Author:** [@amaclean](https://discourse.vtk.org/u/amaclean)\
**Replies:** 3\
**Last updated:** [July 18, 2019, 10:57pm UTC](https://discourse.vtk.org/t/building-vtk-with-cmake-3-15/1370 "2019-07-18T22:57:23Z")

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The build fails with: CMake Error at Common/Core/CMakeLists.txt:442 (check\_symbol\_exists): Unknown CMake command "check\_symbol\_exists". The fix is to add: include(CheckSymbolExists) However should this be added to …

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## [Free VTK, ParaView, CMake and friends courses to be held at Kitware in NY July 22-25th.](https://discourse.vtk.org/t/free-vtk-paraview-cmake-and-friends-courses-to-be-held-at-kitware-in-ny-july-22-25th/1073)

<div class="topic-metadata">

**Author:** [@Dave\_DeMarle](https://discourse.vtk.org/u/Dave_DeMarle)\
**Replies:** 3\
**Last updated:** [July 18, 2019, 12:10pm UTC](https://discourse.vtk.org/t/free-vtk-paraview-cmake-and-friends-courses-to-be-held-at-kitware-in-ny-july-22-25th/1073 "2019-07-18T12:10:28Z")

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Hi All, Kitware is having 4 days of free courses at our Albany NY offices this summer ( July 22-25 ) covering VTK.js, VTK, ParaView, CMake, TomViz, CMB, and Girder. To reserve a seat for the courses, please fill out …

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## [light on 3d data](https://discourse.vtk.org/t/light-on-3d-data/1375)

<div class="topic-metadata">

**Author:** [@kondreti](https://discourse.vtk.org/u/kondreti)\
**Replies:** 0\
**Last updated:** [July 18, 2019, 9:23am UTC](https://discourse.vtk.org/t/light-on-3d-data/1375 "2019-07-18T09:23:51Z")

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How to focus light on 3d object at particular angle

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## [GLFTImporter example added to VTKExamples](https://discourse.vtk.org/t/glftimporter-example-added-to-vtkexamples/1356)

<div class="topic-metadata">

**Author:** [@lorensen](https://discourse.vtk.org/u/lorensen)\
**Replies:** 7\
**Last updated:** [July 18, 2019, 8:29am UTC](https://discourse.vtk.org/t/glftimporter-example-added-to-vtkexamples/1356 "2019-07-18T08:29:34Z")

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Folks, I’ve added a new example, GLFTImporter to the VTK Examples Project. glTF (derivative short form of GL Transmission Format) is a file format for 3D scenes and models using the JSON standard. There are a few issue…

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## [build fails while downloading external data file](https://discourse.vtk.org/t/build-fails-while-downloading-external-data-file/1371)

<div class="topic-metadata">

**Author:** [@andreasbuykx](https://discourse.vtk.org/u/andreasbuykx)\
**Replies:** 2\
**Last updated:** [July 18, 2019, 8:05am UTC](https://discourse.vtk.org/t/build-fails-while-downloading-external-data-file/1371 "2019-07-18T08:05:46Z")

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It’s been a while since I’ve built VTK, and now I updated to 52157f40f47ce4f5be55f223258f1d7bfefcf60e and tried to build my squeaky clean clone of origin/master. I get a failure that some file cannot be downloaded: -- F…

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## [vtkActor2D not always displayed on screen](https://discourse.vtk.org/t/vtkactor2d-not-always-displayed-on-screen/1374)

<div class="topic-metadata">

**Author:** [@Aramos](https://discourse.vtk.org/u/Aramos)\
**Replies:** 0\
**Last updated:** [July 18, 2019, 7:58am UTC](https://discourse.vtk.org/t/vtkactor2d-not-always-displayed-on-screen/1374 "2019-07-18T07:58:29Z")

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Hi all, I’m working on a project where I can interact with different 3D models, one per vtkRenderer (a maximum of 4 vtkRenderers can be opened/loaded with models in the vtkRenderWindow, splitting the screen/RenderWindow…

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## [how to close the vtkRenderWindow with program](https://discourse.vtk.org/t/how-to-close-the-vtkrenderwindow-with-program/1308)

<div class="topic-metadata">

**Author:** [@pingdan](https://discourse.vtk.org/u/pingdan)\
**Replies:** 3\
**Last updated:** [July 17, 2019, 11:50am UTC](https://discourse.vtk.org/t/how-to-close-the-vtkrenderwindow-with-program/1308 "2019-07-17T11:50:34Z")

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I create a vtkRenderWindow and display image. when I click the ‘x’ icon on the top right ,the vtkRenderWindow can close. Now I want to know how can I close the window with program code.

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## [vtkPolyData with vtkTetra](https://discourse.vtk.org/t/vtkpolydata-with-vtktetra/1355)

<div class="topic-metadata">

**Author:** [@marcomusy](https://discourse.vtk.org/u/marcomusy)\
**Replies:** 2\
**Last updated:** [July 17, 2019, 10:50am UTC](https://discourse.vtk.org/t/vtkpolydata-with-vtktetra/1355 "2019-07-17T10:50:18Z")

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In this slightly modified version of this example: import vtk points = vtk.vtkPoints() points.InsertNextPoint(0, 0, 0) points.InsertNextPoint(1, 0, 0) points.InsertNextPoint(1, 1, 0) points.InsertNextPoint(0, 1, 1) po…

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## [vtkColorTransferFunction's color spaces](https://discourse.vtk.org/t/vtkcolortransferfunctions-color-spaces/1363)

<div class="topic-metadata">

**Author:** [@embeddedmz](https://discourse.vtk.org/u/embeddedmz)\
**Replies:** 0\
**Last updated:** [July 17, 2019, 9:00am UTC](https://discourse.vtk.org/t/vtkcolortransferfunctions-color-spaces/1363 "2019-07-17T09:00:19Z")

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Hello, vtkColorTransferFunction has 4 color spaces : RGB, HSV, Lab (or CIELAB) and Diverging. Can someone tell me what are exactly Lab and Diverging color spaces ? In code’s comment : Diverging is a special mode whe…

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## [vtkImageViewer2: visualizing RGB data](https://discourse.vtk.org/t/vtkimageviewer2-visualizing-rgb-data/1362)

<div class="topic-metadata">

**Author:** [@Maina](https://discourse.vtk.org/u/Maina)\
**Replies:** 0\
**Last updated:** [July 17, 2019, 7:46am UTC](https://discourse.vtk.org/t/vtkimageviewer2-visualizing-rgb-data/1362 "2019-07-17T07:46:51Z")

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Good morning, I am trying to visualize a RGB image using vtkImageViewer2 in python. The image is a combination of a grayscale CTA image (which I have converted to a 3 channel image using np.stack) and a mask in its red …

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## [Multiple render window interaction/synchronization in vtk](https://discourse.vtk.org/t/multiple-render-window-interaction-synchronization-in-vtk/1360)

<div class="topic-metadata">

**Author:** [@aish](https://discourse.vtk.org/u/aish)\
**Replies:** 0\
**Last updated:** [July 17, 2019, 7:06am UTC](https://discourse.vtk.org/t/multiple-render-window-interaction-synchronization-in-vtk/1360 "2019-07-17T07:06:29Z")

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Hi, Similar questions have been asked multiple time in the past but I couldn’t find a proper answer to this issue. I am trying to implement the 4 panes view thing (axial, coronal, sagittal and 3D(surface render)) usin…

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