# Latest

**URL:** https://discourse.vtk.org/latest.md?page=111

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

**Page:** 112

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## [Line Widget Behind ImageSlice Actor](https://discourse.vtk.org/t/line-widget-behind-imageslice-actor/9812)

<div class="topic-metadata">

**Author:** [@YHJ](https://discourse.vtk.org/u/YHJ)\
**Replies:** 3\
**Last updated:** [November 14, 2022, 8:35am UTC](https://discourse.vtk.org/t/line-widget-behind-imageslice-actor/9812 "2022-11-14T08:35:34Z")

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Hello, I don’t want “LineWidget” to be drawn behind “ImageSlice Actor”. This image is the result of adjusting the “Slice Index”. I tried to adjust the Manipulator of LineWidget’s HandleRepresentations, but the resul…

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## [Seg faults on Render() call](https://discourse.vtk.org/t/seg-faults-on-render-call/9803)

<div class="topic-metadata">

**Author:** [@marcomusy](https://discourse.vtk.org/u/marcomusy)\
**Replies:** 5\
**Last updated:** [November 13, 2022, 4:15pm UTC](https://discourse.vtk.org/t/seg-faults-on-render-call/9803 "2022-11-13T16:15:32Z")

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I’m getting seg fault in my Ubuntu system: vtk version : 9.2.2 python version : 3.9.13 (main, Aug 25 2022, 23:26:10) \[GCC 11.2.0\] python interpreter: /home/musy/soft/anaconda3/bin/python system : Lin…

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## [GPU Use with ResliceCursorWidget](https://discourse.vtk.org/t/gpu-use-with-reslicecursorwidget/9796)

<div class="topic-metadata">

**Author:** [@michaelscott](https://discourse.vtk.org/u/michaelscott)\
**Replies:** 5\
**Last updated:** [November 13, 2022, 1:19pm UTC](https://discourse.vtk.org/t/gpu-use-with-reslicecursorwidget/9796 "2022-11-13T13:19:59Z")

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I am trying to use ResliceCursorWidget with additional components. Currently I display additional actors (spheres) and some polydata, nothing crazy, but it is getting slower. I realized that the GPU is not being used and…

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## [How to find all cells connected to a list of points?](https://discourse.vtk.org/t/how-to-find-all-cells-connected-to-a-list-of-points/9765)

<div class="topic-metadata">

**Author:** [@scotsman60](https://discourse.vtk.org/u/scotsman60)\
**Replies:** 12\
**Last updated:** [November 11, 2022, 9:24pm UTC](https://discourse.vtk.org/t/how-to-find-all-cells-connected-to-a-list-of-points/9765 "2022-11-11T21:24:04Z")

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Hello!!, How can I find the set of cells in a vtkPolyData or vtkUnstructuredGrid that are connected to a set of points? I have a vtkPolyData with a PointData field. I want to find all cells that connect to points where…

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## [Parallel (MPI) point locator](https://discourse.vtk.org/t/parallel-mpi-point-locator/9545)

<div class="topic-metadata">

**Author:** [@a-jp1](https://discourse.vtk.org/u/a-jp1)\
**Replies:** 9\
**Last updated:** [November 10, 2022, 9:52pm UTC](https://discourse.vtk.org/t/parallel-mpi-point-locator/9545 "2022-11-10T21:52:59Z")

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Hi, I’ve made a lot of use of the vtk point locators before, I have a use case that requires me to build and perform nearest neighbour searches of point trees, distributed over MPI. Is that possible in VTK? Thanks,

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## [Beginner Question About VTK.js Proxies](https://discourse.vtk.org/t/beginner-question-about-vtk-js-proxies/9770)

<div class="topic-metadata">

**Author:** [@davidshq](https://discourse.vtk.org/u/davidshq)\
**Replies:** 5\
**Last updated:** [November 10, 2022, 8:49pm UTC](https://discourse.vtk.org/t/beginner-question-about-vtk-js-proxies/9770 "2022-11-10T20:49:42Z")

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Is a VTK.js proxy an implementation of the structural design pattern which: “lets you provide a substitute or placeholder for another object…controls access to the original object, allow\[s\] you to perform something eith…

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## [How do I develop with vtk.js using React](https://discourse.vtk.org/t/how-do-i-develop-with-vtk-js-using-react/9762)

<div class="topic-metadata">

**Author:** [@potkan](https://discourse.vtk.org/u/potkan)\
**Replies:** 4\
**Last updated:** [November 10, 2022, 4:47pm UTC](https://discourse.vtk.org/t/how-do-i-develop-with-vtk-js-using-react/9762 "2022-11-10T16:47:21Z")

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Hello, I’m a university student currently doing my thesis. I will be using vtk.js to visualize .nii.gz files on the web. I’m not that good with pure JavaScript, but I am good enough with developing basic websites using …

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## [Beginner's questions about vtk-react](https://discourse.vtk.org/t/beginners-questions-about-vtk-react/9789)

<div class="topic-metadata">

**Author:** [@Bethel\_001](https://discourse.vtk.org/u/Bethel_001)\
**Replies:** 1\
**Last updated:** [November 10, 2022, 2:53pm UTC](https://discourse.vtk.org/t/beginners-questions-about-vtk-react/9789 "2022-11-10T14:53:20Z")

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Hello everyone, Thanks for helping out with VTK problems. I am new to Vtk-React. I am trying to incorporate vtk code from Using vtk.js with React & Typescript (forked) - CodeSandbox into an existing React project but it …

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## [Shared Library Names](https://discourse.vtk.org/t/shared-library-names/9767)

<div class="topic-metadata">

**Author:** [@henrydeere](https://discourse.vtk.org/u/henrydeere)\
**Replies:** 3\
**Last updated:** [November 9, 2022, 6:30pm UTC](https://discourse.vtk.org/t/shared-library-names/9767 "2022-11-09T18:30:35Z")

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I’ve installed vtk version 9.1.0-r4 on my linux system using the package manager, and have also compiled version 9.1.0-r4 from source The package manager installed version has libraries: libvtkCommon-9.1.so libvtkRend…

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## [Add Line on vtkXYPlotActor](https://discourse.vtk.org/t/add-line-on-vtkxyplotactor/9774)

<div class="topic-metadata">

**Author:** [@fvitello](https://discourse.vtk.org/u/fvitello)\
**Replies:** 1\
**Last updated:** [November 9, 2022, 6:03pm UTC](https://discourse.vtk.org/t/add-line-on-vtkxyplotactor/9774 "2022-11-09T18:03:44Z")

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Hi, Is possibile to add a vertical line (with a different color) in a vtkXYPlotActor plot created from a vtkImageProbeFilter dataset? Thanks

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## [Image Profile](https://discourse.vtk.org/t/image-profile/9768)

<div class="topic-metadata">

**Author:** [@fvitello](https://discourse.vtk.org/u/fvitello)\
**Replies:** 6\
**Last updated:** [November 9, 2022, 5:18pm UTC](https://discourse.vtk.org/t/image-profile/9768 "2022-11-09T17:18:36Z")

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Hi There, I want to implement in my application the possibility to have an xy plot of the intensity values of an image along the X or the Y axis. I have tried to draw vtkLineSource on top of my image and extract the …

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## [Can one do point interpolation with VTK.js?](https://discourse.vtk.org/t/can-one-do-point-interpolation-with-vtk-js/9759)

<div class="topic-metadata">

**Author:** [@joaomlap](https://discourse.vtk.org/u/joaomlap)\
**Replies:** 3\
**Last updated:** [November 9, 2022, 10:31am UTC](https://discourse.vtk.org/t/can-one-do-point-interpolation-with-vtk-js/9759 "2022-11-09T10:31:28Z")

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Hi I am interested in knowing if Point Interpolation is possible using VTK.js. My use case is for CFD data post processing data analysis where I have for example two PolyData objects with similar but not equal meshes an…

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## [How to get VTK9 + Qt6 working together?](https://discourse.vtk.org/t/how-to-get-vtk9-qt6-working-together/4927)

<div class="topic-metadata">

**Author:** [@NameRakes](https://discourse.vtk.org/u/NameRakes)\
**Replies:** 19\
**Last updated:** [November 9, 2022, 9:01am UTC](https://discourse.vtk.org/t/how-to-get-vtk9-qt6-working-together/4927 "2022-11-09T09:01:50Z")

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I managed to get VTK9 to compile and work with Qt 5.15.2. But my goal is to use Qt6 which was released earlier this month. Key questions are: Can I modify CMake variables (like Qt5\_DIR, etc.) and get it to work with Qt…

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## [Need help to add text and ruler to the vtk scene](https://discourse.vtk.org/t/need-help-to-add-text-and-ruler-to-the-vtk-scene/9771)

<div class="topic-metadata">

**Author:** [@gzt036](https://discourse.vtk.org/u/gzt036)\
**Replies:** 1\
**Last updated:** [November 9, 2022, 1:14am UTC](https://discourse.vtk.org/t/need-help-to-add-text-and-ruler-to-the-vtk-scene/9771 "2022-11-09T01:14:16Z")

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what is the best and proper way to add text and ruler to vtk renderer, I searched and found the closest one is How can i use the vtkActor2D? · Issue #1712 · Kitware/vtk-js · GitHub " If you are just looking to add an S…

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## [How can I change the Input Array to Process on a Tube Filter after it's been initialized?](https://discourse.vtk.org/t/how-can-i-change-the-input-array-to-process-on-a-tube-filter-after-its-been-initialized/9761)

<div class="topic-metadata">

**Author:** [@NickYoung](https://discourse.vtk.org/u/NickYoung)\
**Replies:** 8\
**Last updated:** [November 8, 2022, 9:37pm UTC](https://discourse.vtk.org/t/how-can-i-change-the-input-array-to-process-on-a-tube-filter-after-its-been-initialized/9761 "2022-11-08T21:37:41Z")

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I followed this example here: vtk.js I am able to get my PolyData to render with the Tube Filter and use setInputArrayToProcess to get the right color map to render during the initial pipeline creation. However, if I t…

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## [Clipping data with manually constructed closed surface polyData.](https://discourse.vtk.org/t/clipping-data-with-manually-constructed-closed-surface-polydata/9538)

<div class="topic-metadata">

**Author:** [@ugis](https://discourse.vtk.org/u/ugis)\
**Replies:** 11\
**Last updated:** [November 8, 2022, 5:24pm UTC](https://discourse.vtk.org/t/clipping-data-with-manually-constructed-closed-surface-polydata/9538 "2022-11-08T17:24:56Z")

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Hi everyone, I have the following task I want to accomplish. I have results I would like to clip to a specified shape. The shape in my case is constructed via number of 2D polygon surfaces, that combined define an enclo…

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## [Colorize self-created Polydata](https://discourse.vtk.org/t/colorize-self-created-polydata/9674)

<div class="topic-metadata">

**Author:** [@sunlin0oo](https://discourse.vtk.org/u/sunlin0oo)\
**Replies:** 8\
**Last updated:** [November 8, 2022, 1:20pm UTC](https://discourse.vtk.org/t/colorize-self-created-polydata/9674 "2022-11-08T13:20:18Z")

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Hello everyone! I think there are some problems with coloring the self-created Polydata, I need everyone’s help. First,I only have point data and cell data in my Polydata data; Here is part of the code for (let edgeId…

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## [Widget Interactor Slowing (Overlapping) Issues](https://discourse.vtk.org/t/widget-interactor-slowing-overlapping-issues/9764)

<div class="topic-metadata">

**Author:** [@YHJ](https://discourse.vtk.org/u/YHJ)\
**Replies:** 3\
**Last updated:** [November 8, 2022, 7:24am UTC](https://discourse.vtk.org/t/widget-interactor-slowing-overlapping-issues/9764 "2022-11-08T07:24:45Z")

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Hello, I’m using LineWidget (See example code) and the following warning appears. \[Violation\] ‘pointerdown’ handler took 364ms Perhaps the problem is over-calling due to Event Bubbling or Capturing. The view I’m conf…

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## [Need help to understand how to set ResliceAxes for imageReslice](https://discourse.vtk.org/t/need-help-to-understand-how-to-set-resliceaxes-for-imagereslice/9697)

<div class="topic-metadata">

**Author:** [@gzt036](https://discourse.vtk.org/u/gzt036)\
**Replies:** 14\
**Last updated:** [November 8, 2022, 7:16am UTC](https://discourse.vtk.org/t/need-help-to-understand-how-to-set-resliceaxes-for-imagereslice/9697 "2022-11-08T07:16:53Z")

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I had a hard time to use imageReslice. Basically the only thing required here is ResliceAxes. I checked the instruction but doesn’t seem to work well for me. so I checked the source code vtk.js\\Sources\\Widgets\\Widgets3D\\…

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## [How to remove all actors from a renderer?](https://discourse.vtk.org/t/how-to-remove-all-actors-from-a-renderer/9763)

<div class="topic-metadata">

**Author:** [@Tomasso](https://discourse.vtk.org/u/Tomasso)\
**Replies:** 1\
**Last updated:** [November 8, 2022, 12:27am UTC](https://discourse.vtk.org/t/how-to-remove-all-actors-from-a-renderer/9763 "2022-11-08T00:27:54Z")

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Is it possible to remove all actors from a renderer in VTK-9.3.0? This old post indicates that past VTK versions included vtkRenderer::RemoveAllViewProps(), but that method is no longer supported. Thanks!

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## [The program in VTK 8.1 can't work in VTK 9.2](https://discourse.vtk.org/t/the-program-in-vtk-8-1-cant-work-in-vtk-9-2/9753)

<div class="topic-metadata">

**Author:** [@supersteven](https://discourse.vtk.org/u/supersteven)\
**Replies:** 1\
**Last updated:** [November 7, 2022, 5:35pm UTC](https://discourse.vtk.org/t/the-program-in-vtk-8-1-cant-work-in-vtk-9-2/9753 "2022-11-07T17:35:25Z")

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The program is as follows, which works well in VTK8.2 : //vtkNew\<vtkGPUVolumeRayCastMapper\> volumeMapper; vtkSmartPointer\<vtkGPUVolumeRayCastMapper\> volumeMapper = vtkSmartPointer\<vtkGPUVolumeRayCastMapper\>::New(); volu…

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## [Are there any examples of multiple images being rendered by VTK.js side-by-side?](https://discourse.vtk.org/t/are-there-any-examples-of-multiple-images-being-rendered-by-vtk-js-side-by-side/9740)

<div class="topic-metadata">

**Author:** [@davidshq](https://discourse.vtk.org/u/davidshq)\
**Replies:** 3\
**Last updated:** [November 7, 2022, 3:15pm UTC](https://discourse.vtk.org/t/are-there-any-examples-of-multiple-images-being-rendered-by-vtk-js-side-by-side/9740 "2022-11-07T15:15:47Z")

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For example, if I wanted to view side-by-side the CT scans for three different individuals using VTK.js? Thanks!

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## [vtk: how to read ply with colors?](https://discourse.vtk.org/t/vtk-how-to-read-ply-with-colors/9749)

<div class="topic-metadata">

**Author:** [@zhang-qiang-github](https://discourse.vtk.org/u/zhang-qiang-github)\
**Replies:** 0\
**Last updated:** [November 7, 2022, 5:32am UTC](https://discourse.vtk.org/t/vtk-how-to-read-ply-with-colors/9749 "2022-11-07T05:32:51Z")

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I have a ply file, which is generated from Solidworks: cube.PLY (137 KB). This ply file is colored. I want to load it, and display it with vtk. My code is: import vtkmodules.all as vtk reader = vtk.vtkPLYReader() read…

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## [VTK Examples - New Physically Based Rendering examples](https://discourse.vtk.org/t/vtk-examples-new-physically-based-rendering-examples/9737)

<div class="topic-metadata">

**Author:** [@amaclean](https://discourse.vtk.org/u/amaclean)\
**Replies:** 4\
**Last updated:** [November 7, 2022, 3:20am UTC](https://discourse.vtk.org/t/vtk-examples-new-physically-based-rendering-examples/9737 "2022-11-07T03:20:30Z")

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I have added fourteen PBR examples to vtk-examples. They are: C++ Python Description PBR Anisotropy PBR Anisotropy Render spheres with different anisotropy values. PBR\_Clear\_Coat PBR\_Clear\_Coat Render a cube …

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## [vtk9 vtkLookupTable transparency](https://discourse.vtk.org/t/vtk9-vtklookuptable-transparency/9728)

<div class="topic-metadata">

**Author:** [@Nil](https://discourse.vtk.org/u/Nil)\
**Replies:** 5\
**Last updated:** [November 4, 2022, 6:35pm UTC](https://discourse.vtk.org/t/vtk9-vtklookuptable-transparency/9728 "2022-11-04T18:35:50Z")

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I’m trying to take a screenshot (vtkWindowToImageFilter) of a 4x4 toy image with a vtkLookupTable that transform NaN values into transparent values. Here’s my code: import numpy as np import vtk data = np.array( \[ …

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## [How to use the SelectExamples](https://discourse.vtk.org/t/how-to-use-the-selectexamples/8756)

<div class="topic-metadata">

**Author:** [@Dwight98](https://discourse.vtk.org/u/Dwight98)\
**Replies:** 3\
**Last updated:** [June 23, 2022, 8:14am UTC](https://discourse.vtk.org/t/how-to-use-the-selectexamples/8756 "2022-06-23T08:14:04Z")

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I want to use the SelectExamples to look through some examples about vtk class which i need,but i don’t know where can modify the vtk\_class and language,I ran the official example code directly and got the following erro…

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## [How to get gradual transition between discrete LUT colors?](https://discourse.vtk.org/t/how-to-get-gradual-transition-between-discrete-lut-colors/9736)

<div class="topic-metadata">

**Author:** [@Tomasso](https://discourse.vtk.org/u/Tomasso)\
**Replies:** 7\
**Last updated:** [November 4, 2022, 12:30am UTC](https://discourse.vtk.org/t/how-to-get-gradual-transition-between-discrete-lut-colors/9736 "2022-11-04T00:30:50Z")

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I am writing an app with VTK-9.3.0 to display seafloor bathymetry. I would like to assign a colormap so that color varies between discrete color values in a gradual way as shown in the figure on the left, using discrete …

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## [vtkLASReader()](https://discourse.vtk.org/t/vtklasreader/438)

<div class="topic-metadata">

**Author:** [@clairecita](https://discourse.vtk.org/u/clairecita)\
**Replies:** 5\
**Last updated:** [March 19, 2019, 12:47am UTC](https://discourse.vtk.org/t/vtklasreader/438 "2019-03-19T00:47:02Z")

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Hi, I saw somewhere that vtk has a reader for .las files (lidar data) (vtkLASReader) but when I try to use it it says that there is no such attribute. What am I missing ?

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## [Cell picker using HardwareSelector](https://discourse.vtk.org/t/cell-picker-using-hardwareselector/9700)

<div class="topic-metadata">

**Author:** [@MarKara](https://discourse.vtk.org/u/MarKara)\
**Replies:** 3\
**Last updated:** [November 3, 2022, 12:49pm UTC](https://discourse.vtk.org/t/cell-picker-using-hardwareselector/9700 "2022-11-03T12:49:09Z")

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I know this question is raised before but I still cannot find definite answer how to use hardwareselector. I’m using ActiViz 9.2 and have the same problem discussed here How to select a hexahedral cell using HardwareSe…

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## [After add actor to render, can i change the actor data real time ?](https://discourse.vtk.org/t/after-add-actor-to-render-can-i-change-the-actor-data-real-time/9724)

<div class="topic-metadata">

**Author:** [@herman](https://discourse.vtk.org/u/herman)\
**Replies:** 2\
**Last updated:** [November 3, 2022, 7:53am UTC](https://discourse.vtk.org/t/after-add-actor-to-render-can-i-change-the-actor-data-real-time/9724 "2022-11-03T07:53:22Z")

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Dear vtk users: As we know, after add actor to render, we can change the properties of the actor. Now I tried to change the data of the actor,but it does not work. My code is as below: //////////////////////////////…

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