# Latest

**URL:** https://discourse.vtk.org/latest.md?page=98

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

**Page:** 99

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## [How to determine the first vertex of a regular polygon drawn with vtk.vtkRegularPolygonSource()?](https://discourse.vtk.org/t/how-to-determine-the-first-vertex-of-a-regular-polygon-drawn-with-vtk-vtkregularpolygonsource/10691)

<div class="topic-metadata">

**Author:** [@jumbojing](https://discourse.vtk.org/u/jumbojing)\
**Replies:** 1\
**Last updated:** [February 15, 2023, 12:40pm UTC](https://discourse.vtk.org/t/how-to-determine-the-first-vertex-of-a-regular-polygon-drawn-with-vtk-vtkregularpolygonsource/10691 "2023-02-15T12:40:35Z")

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How to determine the first vertex of a regular polygon drawn with vtk.vtkRegularPolygonSource()? Or What is the projection direction of the coordinates of the first vertex of a regular polygon drawn with vtk.vtkRegula…

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## [How to access vtkTexture in vtk shader?](https://discourse.vtk.org/t/how-to-access-vtktexture-in-vtk-shader/10678)

<div class="topic-metadata">

**Author:** [@Reshma\_R\_S](https://discourse.vtk.org/u/Reshma_R_S)\
**Replies:** 3\
**Last updated:** [February 15, 2023, 11:55am UTC](https://discourse.vtk.org/t/how-to-access-vtktexture-in-vtk-shader/10678 "2023-02-15T11:55:48Z")

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I have used the tutorial Shaders In VTK - KitwarePublic to implement a basic shader in my python vtk program. I know that we can create a texture by using vtk.vtkTexture() class, but I don’t know how I can pass or use th…

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## [VTK 9.2.2 build aborts](https://discourse.vtk.org/t/vtk-9-2-2-build-aborts/10025)

<div class="topic-metadata">

**Author:** [@BlueKnight7](https://discourse.vtk.org/u/BlueKnight7)\
**Replies:** 17\
**Last updated:** [February 15, 2023, 7:14am UTC](https://discourse.vtk.org/t/vtk-9-2-2-build-aborts/10025 "2023-02-15T07:14:37Z")

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I’m trying to build 9.2.2 with GCC 4.8.5 where I’m taking all of the defaults except that I select a RELASE build and I set VTK\_GUISupportQtQuick to NO. All selections are made with ccmake. This is what I see: In file…

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## [How to load PLY files based on POINT CLODE](https://discourse.vtk.org/t/how-to-load-ply-files-based-on-point-clode/10686)

<div class="topic-metadata">

**Author:** [@JYM](https://discourse.vtk.org/u/JYM)\
**Replies:** 1\
**Last updated:** [February 15, 2023, 6:53am UTC](https://discourse.vtk.org/t/how-to-load-ply-files-based-on-point-clode/10686 "2023-02-15T06:53:20Z")

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Hello I am trying to load the fly file from VTK 9.0. The language is using c++. Mesh-based data is loaded, but the point cloud ply file is not loaded. Can I have an example code? DATA FILE

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## [question about the vtkBoxWidget is blocked](https://discourse.vtk.org/t/question-about-the-vtkboxwidget-is-blocked/10685)

<div class="topic-metadata">

**Author:** [@tong\_yang](https://discourse.vtk.org/u/tong_yang)\
**Replies:** 0\
**Last updated:** [February 15, 2023, 6:07am UTC](https://discourse.vtk.org/t/question-about-the-vtkboxwidget-is-blocked/10685 "2023-02-15T06:07:06Z")

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Excuse me, is there any way to make this white box display first without being blocked? I use vtkBoxWidget to realize this white box.

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## [Odd color problem with vtkCubeAxesActor](https://discourse.vtk.org/t/odd-color-problem-with-vtkcubeaxesactor/10659)

<div class="topic-metadata">

**Author:** [@BlueKnight7](https://discourse.vtk.org/u/BlueKnight7)\
**Replies:** 1\
**Last updated:** [February 14, 2023, 10:32pm UTC](https://discourse.vtk.org/t/odd-color-problem-with-vtkcubeaxesactor/10659 "2023-02-14T22:32:45Z")

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Working with the online example: https://kitware.github.io/vtk-examples/site/Cxx/Utilities/DetermineActorType/ I added the following lines to show inner grid lines and set the ones for the X axis to a red-like color p…

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## [Is it possible that vtk implements pagelod, similar to osg](https://discourse.vtk.org/t/is-it-possible-that-vtk-implements-pagelod-similar-to-osg/10664)

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**Author:** [@kingui1106](https://discourse.vtk.org/u/kingui1106)\
**Replies:** 2\
**Last updated:** [February 14, 2023, 10:26pm UTC](https://discourse.vtk.org/t/is-it-possible-that-vtk-implements-pagelod-similar-to-osg/10664 "2023-02-14T22:26:36Z")

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osg pagelod example PagedLOD - FlightGear wiki

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## [Read PLY and texture](https://discourse.vtk.org/t/read-ply-and-texture/10673)

<div class="topic-metadata">

**Author:** [@micheleivani](https://discourse.vtk.org/u/micheleivani)\
**Replies:** 1\
**Last updated:** [February 14, 2023, 10:25pm UTC](https://discourse.vtk.org/t/read-ply-and-texture/10673 "2023-02-14T22:25:11Z")

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Hello, I have a ply file and the realated texture in a separate JPG file. How can I render the 3D window the model with the colors? var filename = Path.Combine(basePath, "lower.ply"); var filenameTexture = Path.Combine…

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## [How to volume rendering raw file what was wrrite by C++ stl;](https://discourse.vtk.org/t/how-to-volume-rendering-raw-file-what-was-wrrite-by-c-stl/10669)

<div class="topic-metadata">

**Author:** [@wulicheng](https://discourse.vtk.org/u/wulicheng)\
**Replies:** 1\
**Last updated:** [February 14, 2023, 10:22pm UTC](https://discourse.vtk.org/t/how-to-volume-rendering-raw-file-what-was-wrrite-by-c-stl/10669 "2023-02-14T22:22:43Z")

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I was write a raw file liking this: unsigned long FileSize = 0;//height \* width \* slices; const Uint16\* FileData = new Uint16(FileSize); metaInfo-\>findAndGetUint16Array(DCM\_PixelData, FileData, &FileSize); //\_strFileNam…

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## [I cannot use QVTKOpenGLNativeWidget to normal display a widgets?](https://discourse.vtk.org/t/i-cannot-use-qvtkopenglnativewidget-to-normal-display-a-widgets/10683)

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**Author:** [@Arvin](https://discourse.vtk.org/u/Arvin)\
**Replies:** 0\
**Last updated:** [February 14, 2023, 9:40pm UTC](https://discourse.vtk.org/t/i-cannot-use-qvtkopenglnativewidget-to-normal-display-a-widgets/10683 "2023-02-14T21:40:30Z")

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there is my code , i want to add a coordinate like this the follow is my code curvessurfaces.h #ifndef CURVESSURFACES\_H #define CURVESSURFACES\_H #include \<QMainWindow\> #include \<QVTKOpenGLNativeWidget.h\> #include \<v…

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## [vtkRenderWindowInteractor on OSX](https://discourse.vtk.org/t/vtkrenderwindowinteractor-on-osx/10667)

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**Author:** [@marcomusy](https://discourse.vtk.org/u/marcomusy)\
**Replies:** 1\
**Last updated:** [February 14, 2023, 12:28am UTC](https://discourse.vtk.org/t/vtkrenderwindowinteractor-on-osx/10667 "2023-02-14T00:28:58Z")

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The vtkRenderWindowInteractor class has some erratic behavior, on ubuntu I get a seg fault sometimes when interacting with the scene and pressing q at the same time. On OSX the rendering window doesn’t close unless anoth…

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## [Strange behaviour while changing camera settings of a scene](https://discourse.vtk.org/t/strange-behaviour-while-changing-camera-settings-of-a-scene/10662)

<div class="topic-metadata">

**Author:** [@Pierre-yves\_Meyer](https://discourse.vtk.org/u/Pierre-yves_Meyer)\
**Replies:** 2\
**Last updated:** [February 13, 2023, 10:27pm UTC](https://discourse.vtk.org/t/strange-behaviour-while-changing-camera-settings-of-a-scene/10662 "2023-02-13T22:27:30Z")

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Hello all, I have a scene that is composed of two actors, one made out of a sphere and another is a point cloud with a sphere mapper. After some user interactions (changes in the camera), I’m trying to come back to the…

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## [Surface nets and marching cubes](https://discourse.vtk.org/t/surface-nets-and-marching-cubes/7844)

<div class="topic-metadata">

**Author:** [@wael869](https://discourse.vtk.org/u/wael869)\
**Replies:** 6\
**Last updated:** [February 10, 2023, 4:10pm UTC](https://discourse.vtk.org/t/surface-nets-and-marching-cubes/7844 "2023-02-10T16:10:03Z")

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Can we use surface nets algorithm instead of marching cubes for isosurface generation?

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## [How to select the object and get its unique ID in VTK VB.net?](https://discourse.vtk.org/t/how-to-select-the-object-and-get-its-unique-id-in-vtk-vb-net/10655)

<div class="topic-metadata">

**Author:** [@Ahmed\_Anas](https://discourse.vtk.org/u/Ahmed_Anas)\
**Replies:** 0\
**Last updated:** [February 10, 2023, 1:06pm UTC](https://discourse.vtk.org/t/how-to-select-the-object-and-get-its-unique-id-in-vtk-vb-net/10655 "2023-02-10T13:06:31Z")

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Lets say I have an object i.e. vtkLineSource. I have drawn it using the code. Public Sub CreateLine(x1 As Double, y1 As Double, z1 As Double, x2 As Double, y2 As Double, z2 As Double, …

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## [Is it possible to draw a roi(rectangle) on the vtkImageViewer2?](https://discourse.vtk.org/t/is-it-possible-to-draw-a-roi-rectangle-on-the-vtkimageviewer2/4772)

<div class="topic-metadata">

**Author:** [@Kim\_William](https://discourse.vtk.org/u/Kim_William)\
**Replies:** 2\
**Last updated:** [February 9, 2023, 4:15pm UTC](https://discourse.vtk.org/t/is-it-possible-to-draw-a-roi-rectangle-on-the-vtkimageviewer2/4772 "2023-02-09T16:15:27Z")

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Hi all. I have a question about the vtkImageViewer2. I would like to draw an ROI box and move/drag it. For example: I made it using GDI++. Does VTK provide this function on the vtkImageViewer2? I have tested some…

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## [order of returned points for a cell](https://discourse.vtk.org/t/order-of-returned-points-for-a-cell/10650)

<div class="topic-metadata">

**Author:** [@sarmad](https://discourse.vtk.org/u/sarmad)\
**Replies:** 2\
**Last updated:** [February 9, 2023, 3:45pm UTC](https://discourse.vtk.org/t/order-of-returned-points-for-a-cell/10650 "2023-02-09T15:45:37Z")

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I am reading open foam data and for a specific type of cells for example QUAD, i store the point ids in an array. To get the point ids i use vtkIdList \*pointIds = currentCell-\>GetPointIds(). My question here is, what d…

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## [Pyvista based on vtk kernel cannot draw and display all edges of the mesh in vtk files.](https://discourse.vtk.org/t/pyvista-based-on-vtk-kernel-cannot-draw-and-display-all-edges-of-the-mesh-in-vtk-files/10299)

<div class="topic-metadata">

**Author:** [@csmx](https://discourse.vtk.org/u/csmx)\
**Replies:** 3\
**Last updated:** [February 9, 2023, 3:22am UTC](https://discourse.vtk.org/t/pyvista-based-on-vtk-kernel-cannot-draw-and-display-all-edges-of-the-mesh-in-vtk-files/10299 "2023-02-09T03:22:42Z")

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When I used Pyvista to display the mesh model in vtk file, I found that Pyvista based on vtk kernel cannot draw and display all edges of the mesh in vtk files. Please help solve this problem. Many thanks. Here i…

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## [GitLab code review process and documentation updated](https://discourse.vtk.org/t/gitlab-code-review-process-and-documentation-updated/10271)

<div class="topic-metadata">

**Author:** [@mwestphal](https://discourse.vtk.org/u/mwestphal)\
**Replies:** 0\
**Last updated:** [December 20, 2022, 9:47am UTC](https://discourse.vtk.org/t/gitlab-code-review-process-and-documentation-updated/10271 "2022-12-20T09:47:30Z")

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The review process documentation has been updated to be coherent with what the robot expect. https://gitlab.kitware.com/vtk/vtk/-/blob/master/Documentation/dev/git/develop.md#leading-line The main take away is. +1 m…

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## [How do I iterate through different MaskInputs on vtkGPUVolumeRayCastMapper](https://discourse.vtk.org/t/how-do-i-iterate-through-different-maskinputs-on-vtkgpuvolumeraycastmapper/10643)

<div class="topic-metadata">

**Author:** [@Oscar](https://discourse.vtk.org/u/Oscar)\
**Replies:** 0\
**Last updated:** [February 8, 2023, 1:58pm UTC](https://discourse.vtk.org/t/how-do-i-iterate-through-different-maskinputs-on-vtkgpuvolumeraycastmapper/10643 "2023-02-08T13:58:07Z")

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I am trying to iterate through different masks using vtkGPUVolumeRayCastMapper-\>SetMaskInput() but its only working with the first iteration. The second time I call the function with a different maskImage does not produc…

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## [error: incomplete type 'vtkOStreamWrapper::std\_string' used in type trait expression](https://discourse.vtk.org/t/error-incomplete-type-vtkostreamwrapper-std-string-used-in-type-trait-expression/10639)

<div class="topic-metadata">

**Author:** [@qi\_li](https://discourse.vtk.org/u/qi_li)\
**Replies:** 1\
**Last updated:** [February 8, 2023, 1:48am UTC](https://discourse.vtk.org/t/error-incomplete-type-vtkostreamwrapper-std-string-used-in-type-trait-expression/10639 "2023-02-08T01:48:53Z")

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Hello, did anyone knows where is the definition of the forward declaration class std\_string in tkOStreamWrapper.h. Then I can include this file to make the std\_string complete. I have searched all the head files, didn’t …

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## [Some questions about changes in the image display](https://discourse.vtk.org/t/some-questions-about-changes-in-the-image-display/10566)

<div class="topic-metadata">

**Author:** [@HWsir](https://discourse.vtk.org/u/HWsir)\
**Replies:** 4\
**Last updated:** [February 8, 2023, 12:49am UTC](https://discourse.vtk.org/t/some-questions-about-changes-in-the-image-display/10566 "2023-02-08T00:49:24Z")

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What can I do to set a button on the page that controls the passing of parameters in the writing function, which affects the display of the image

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## [Efficient use of vtkPolyDataNormals to show smooth surfaces](https://discourse.vtk.org/t/efficient-use-of-vtkpolydatanormals-to-show-smooth-surfaces/10635)

<div class="topic-metadata">

**Author:** [@sotodela](https://discourse.vtk.org/u/sotodela)\
**Replies:** 6\
**Last updated:** [February 7, 2023, 2:28pm UTC](https://discourse.vtk.org/t/efficient-use-of-vtkpolydatanormals-to-show-smooth-surfaces/10635 "2023-02-07T14:28:41Z")

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Hi, I am using vtkLookupTable() and vtkUnsignedCharArray() to re-color a mesh. The Array that contains the colors is modified several times interactively. The problem I have is that to show the actor with a smooth surf…

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## [About inlined multiblock and partitioned dataset XML data format](https://discourse.vtk.org/t/about-inlined-multiblock-and-partitioned-dataset-xml-data-format/10507)

<div class="topic-metadata">

**Author:** [@mwestphal](https://discourse.vtk.org/u/mwestphal)\
**Replies:** 10\
**Last updated:** [February 7, 2023, 9:19am UTC](https://discourse.vtk.org/t/about-inlined-multiblock-and-partitioned-dataset-xml-data-format/10507 "2023-02-07T09:19:28Z")

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Currently, .vtm (multiblock), .vtpd (partitioned dataset) and .vtpc (partitioned dataset collection) only support file pointers. eg: \<?xml version="1.0"?\> \<VTKFile type="vtkPartitionedDataSet" version="1.0" byte\_order=…

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## [Unexpected dark area in ShadowsLightsDemo (?)](https://discourse.vtk.org/t/unexpected-dark-area-in-shadowslightsdemo/10515)

<div class="topic-metadata">

**Author:** [@estan](https://discourse.vtk.org/u/estan)\
**Replies:** 3\
**Last updated:** [February 7, 2023, 7:57am UTC](https://discourse.vtk.org/t/unexpected-dark-area-in-shadowslightsdemo/10515 "2023-02-07T07:57:58Z")

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EDIT: Moved topic to the Development category since it’s about one of the official examples. Hope this is OK. Let me know if I should move it back to Support. Hi folks, Probably I’m just missing something, but I tried …

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## [mark](https://discourse.vtk.org/t/mark/10554)

<div class="topic-metadata">

**Author:** [@jane](https://discourse.vtk.org/u/jane)\
**Replies:** 3\
**Last updated:** [February 6, 2023, 4:10pm UTC](https://discourse.vtk.org/t/mark/10554 "2023-02-06T16:10:47Z")

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Hello, how to sketch and annotate three-dimensional images?Can I sketch a 3D image drawn by a volume? If so, how?

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## [How to contribute examples to the wiki?](https://discourse.vtk.org/t/how-to-contribute-examples-to-the-wiki/10622)

<div class="topic-metadata">

**Author:** [@rexthor](https://discourse.vtk.org/u/rexthor)\
**Replies:** 2\
**Last updated:** [February 6, 2023, 2:05pm UTC](https://discourse.vtk.org/t/how-to-contribute-examples-to-the-wiki/10622 "2023-02-06T14:05:09Z")

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I guess this sort of is and isn’t a developer question, but, how can I contribute examples to the Python wiki? Also, it looks as if there are Python examples for a number of these already (in the tests) but they aren’t …

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## [VTK file format supporting multiple meshes?](https://discourse.vtk.org/t/vtk-file-format-supporting-multiple-meshes/10598)

<div class="topic-metadata">

**Author:** [@rexthor](https://discourse.vtk.org/u/rexthor)\
**Replies:** 3\
**Last updated:** [February 6, 2023, 1:22pm UTC](https://discourse.vtk.org/t/vtk-file-format-supporting-multiple-meshes/10598 "2023-02-06T13:22:52Z")

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If I wanted to store a torus and a cylinder in a VTK file, what file format would I store it in? I have figured out how to store a vtkPolyData or a vtkUnstructuredGrid … but what if I wanted to store multiples in a file?…

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## [convert file into vtk and stl format](https://discourse.vtk.org/t/convert-file-into-vtk-and-stl-format/10599)

<div class="topic-metadata">

**Author:** [@Abdelkareem\_Elkhateb](https://discourse.vtk.org/u/Abdelkareem_Elkhateb)\
**Replies:** 3\
**Last updated:** [February 6, 2023, 1:10pm UTC](https://discourse.vtk.org/t/convert-file-into-vtk-and-stl-format/10599 "2023-02-06T13:10:20Z")

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I am trying to save a cube into a vtk and stl files! this is the task my question is I read the docs and save it into .ply file this is the stl extension, so how can I save it as a vtk file with python ! i know the quest…

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## [Seeking Feedback and Ideas for Future Improvements on VTK and Jupyter Integration through WebRTC/MJPEG Streaming](https://discourse.vtk.org/t/seeking-feedback-and-ideas-for-future-improvements-on-vtk-and-jupyter-integration-through-webrtc-mjpeg-streaming/10615)

<div class="topic-metadata">

**Author:** [@devmessias](https://discourse.vtk.org/u/devmessias)\
**Replies:** 2\
**Last updated:** [February 6, 2023, 11:03am UTC](https://discourse.vtk.org/t/seeking-feedback-and-ideas-for-future-improvements-on-vtk-and-jupyter-integration-through-webrtc-mjpeg-streaming/10615 "2023-02-06T11:03:28Z")

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Hello, in the 2021 Google Summer of Code, I worked on developing a fast WebRTC-based streaming system for VTK/FURY that enables you to both interact with and expose visualizations in Jupyter, or even expose them over the…

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## [Why does the derived class condition meet or return a null pointer？？](https://discourse.vtk.org/t/why-does-the-derived-class-condition-meet-or-return-a-null-pointer/10495)

<div class="topic-metadata">

**Author:** [@marlon.ma](https://discourse.vtk.org/u/marlon.ma)\
**Replies:** 2\
**Last updated:** [February 6, 2023, 8:16am UTC](https://discourse.vtk.org/t/why-does-the-derived-class-condition-meet-or-return-a-null-pointer/10495 "2023-02-06T08:16:53Z")

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auto maptocolor=vtkImageMapToWindowLevelColors::SafeDownCast(temp); the temp

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