# Latest

**URL:** https://discourse.vtk.org/latest.md?page=219

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

**Page:** 220

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## [CMake 3.17 impossibly slow configuring VTK?](https://discourse.vtk.org/t/cmake-3-17-impossibly-slow-configuring-vtk/2955)

<div class="topic-metadata">

**Author:** [@seanm](https://discourse.vtk.org/u/seanm)\
**Replies:** 5\
**Last updated:** [April 3, 2020, 9:00pm UTC](https://discourse.vtk.org/t/cmake-3-17-impossibly-slow-configuring-vtk/2955 "2020-04-03T21:00:39Z")

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Hi all, Is it just me, or is there a major speed regression with the new CMake 3.17? On two different Macs now I’ve been waiting 10s of minutes for the ‘configure’ step. Steps like this: Looking for frexpl Looking f…

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## [Output video of vtkFFMPEGWriter/any video writer plays too fast](https://discourse.vtk.org/t/output-video-of-vtkffmpegwriter-any-video-writer-plays-too-fast/2942)

<div class="topic-metadata">

**Author:** [@Jafari](https://discourse.vtk.org/u/Jafari)\
**Replies:** 5\
**Last updated:** [April 3, 2020, 4:06pm UTC](https://discourse.vtk.org/t/output-video-of-vtkffmpegwriter-any-video-writer-plays-too-fast/2942 "2020-04-03T16:06:57Z")

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Hi All, Environment: VTK 8.2 .NET 4.5.2 Windows 10 Using VTK 8.2, the output video from all video writers (vtkAVIWriter, vtkOggTheoraWriter, and my preference vtkFFMPEGWriter) plays too fast. It seems that frame rat…

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## [ike not uploading Doxygen documentation](https://discourse.vtk.org/t/ike-not-uploading-doxygen-documentation/2948)

<div class="topic-metadata">

**Author:** [@cory.quammen](https://discourse.vtk.org/u/cory.quammen)\
**Replies:** 2\
**Last updated:** [April 3, 2020, 1:47pm UTC](https://discourse.vtk.org/t/ike-not-uploading-doxygen-documentation/2948 "2020-04-03T13:47:00Z")

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The VTK Doxygen pages haven’t been updated since Feb. 24. The builder ike doesn’t report any errors, so it looks like something is going wrong on the upload. Also, on the VTK Documentation page (https://vtk.org/document…

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## [IntersectWithLine pure 2D](https://discourse.vtk.org/t/intersectwithline-pure-2d/2945)

<div class="topic-metadata">

**Author:** [@a-jp1](https://discourse.vtk.org/u/a-jp1)\
**Replies:** 1\
**Last updated:** [April 2, 2020, 4:38pm UTC](https://discourse.vtk.org/t/intersectwithline-pure-2d/2945 "2020-04-02T16:38:30Z")

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Hi, I’ve used various trees within the vtk api for quite sometime and many of the FindCell\* and IntersectWith\* type functions to great success for 3D meshes. I have a pure 2D mesh now, quads only. Produced from vtkCel…

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## [AttributeError: 'module' object has no attribute 'vtkVolumeTextureMapper3D'](https://discourse.vtk.org/t/attributeerror-module-object-has-no-attribute-vtkvolumetexturemapper3d/2931)

<div class="topic-metadata">

**Author:** [@1117](https://discourse.vtk.org/u/1117)\
**Replies:** 3\
**Last updated:** [April 2, 2020, 1:51pm UTC](https://discourse.vtk.org/t/attributeerror-module-object-has-no-attribute-vtkvolumetexturemapper3d/2931 "2020-04-02T13:51:11Z")

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Hi, What is this error and how to fix it (in python 3.7.6)? thanks

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## [Missing Qt dll](https://discourse.vtk.org/t/missing-qt-dll/2935)

<div class="topic-metadata">

**Author:** [@Tracy\_Nk](https://discourse.vtk.org/u/Tracy_Nk)\
**Replies:** 6\
**Last updated:** [April 2, 2020, 12:17pm UTC](https://discourse.vtk.org/t/missing-qt-dll/2935 "2020-04-02T12:17:29Z")

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I’m running one of the VTK Qt examples and I’m not sure if I’m doing this correctly. I’ve configured and generated on CMake, then built on Visual Studio, then used Command Prompt to open the executable file however I get…

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## [How to create a texture from a image getting by ajax](https://discourse.vtk.org/t/how-to-create-a-texture-from-a-image-getting-by-ajax/2940)

<div class="topic-metadata">

**Author:** [@xuexl](https://discourse.vtk.org/u/xuexl)\
**Replies:** 0\
**Last updated:** [April 2, 2020, 9:45am UTC](https://discourse.vtk.org/t/how-to-create-a-texture-from-a-image-getting-by-ajax/2940 "2020-04-02T09:45:32Z")

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Getting the data that contains obj, mtl and jpg from the server by ajax, the data of obj and mtl can handle in the right way, but no texture. And i want to create a vtkTexture Object to stick on the vtkActor from the jp…

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## [Can surface scalar data be stored on a vtkUnstructuredGrid?](https://discourse.vtk.org/t/can-surface-scalar-data-be-stored-on-a-vtkunstructuredgrid/2938)

<div class="topic-metadata">

**Author:** [@vchan1186](https://discourse.vtk.org/u/vchan1186)\
**Replies:** 3\
**Last updated:** [April 2, 2020, 2:51am UTC](https://discourse.vtk.org/t/can-surface-scalar-data-be-stored-on-a-vtkunstructuredgrid/2938 "2020-04-02T02:51:39Z")

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Dear VTK experts, Is it possible to visualize scalar attributes on the faces of a vtkUnstructuredGrid, which also contains scalar attributes at each cell? Currently, I am outputting two separate files for storing the un…

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## [units of vtkNIFTIheader.GetPixDim()](https://discourse.vtk.org/t/units-of-vtkniftiheader-getpixdim/2929)

<div class="topic-metadata">

**Author:** [@msmerps](https://discourse.vtk.org/u/msmerps)\
**Replies:** 2\
**Last updated:** [April 2, 2020, 2:32am UTC](https://discourse.vtk.org/t/units-of-vtkniftiheader-getpixdim/2929 "2020-04-02T02:32:12Z")

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Hi all, I am using vtkNIFTIheader.GetPixDim() to get the spacing of NIFTI files. Can I assume that values it returns are in units of millimeters? thank you in advance, -Merps

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## [OSPRay 2.0 WIP](https://discourse.vtk.org/t/ospray-2-0-wip/2937)

<div class="topic-metadata">

**Author:** [@aowen](https://discourse.vtk.org/u/aowen)\
**Replies:** 1\
**Last updated:** [April 2, 2020, 1:46am UTC](https://discourse.vtk.org/t/ospray-2-0-wip/2937 "2020-04-02T01:46:34Z")

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Hello, I noticed from this discussion here, https://discourse.vtk.org/t/ospray-2-0-vtk-9-0/2789, that there is a lot of work going into integrating OSPRay 2.0 into VTK. That’s great news! I checked out this branch, buil…

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## [iOS framework](https://discourse.vtk.org/t/ios-framework/1607)

<div class="topic-metadata">

**Author:** [@leon](https://discourse.vtk.org/u/leon)\
**Replies:** 10\
**Last updated:** [April 2, 2020, 12:05am UTC](https://discourse.vtk.org/t/ios-framework/1607 "2020-04-02T00:05:12Z")

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I want to use VTK in ios. According to the instructions, I plan to Build the vtk.framework of ios, but it is prompted in make that VTK not installed. Build the source then Build the ‘install’ target。The vtk.framework gen…

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## [Processing ExodusII data](https://discourse.vtk.org/t/processing-exodusii-data/2885)

<div class="topic-metadata">

**Author:** [@nikhilgv](https://discourse.vtk.org/u/nikhilgv)\
**Replies:** 1\
**Last updated:** [April 1, 2020, 3:43pm UTC](https://discourse.vtk.org/t/processing-exodusii-data/2885 "2020-04-01T15:43:19Z")

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Hello, I am new to VTK. Here is what I need to do: Read exodusII file. The exodus file contains spatio-temporal data for multiple scalar variables. Choose a particular scalar variable. Apply a threshold filter to the …

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## [Problem for saving image to png](https://discourse.vtk.org/t/problem-for-saving-image-to-png/2924)

<div class="topic-metadata">

**Author:** [@NeuZhangQiang](https://discourse.vtk.org/u/NeuZhangQiang)\
**Replies:** 4\
**Last updated:** [April 1, 2020, 10:04am UTC](https://discourse.vtk.org/t/problem-for-saving-image-to-png/2924 "2020-04-01T10:04:59Z")

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I want to save a image to png, and it is OK. However, when I read it, bug happens. The code is: vtkSmartPointer\<vtkPNGWriter\> imgWriter = vtkSmartPointer\<vtkPNGWriter\>::New(); imgWriter-\>SetInputData(img); img…

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## [self intersections from extrusion](https://discourse.vtk.org/t/self-intersections-from-extrusion/2919)

<div class="topic-metadata">

**Author:** [@mikewho](https://discourse.vtk.org/u/mikewho)\
**Replies:** 6\
**Last updated:** [March 31, 2020, 7:52pm UTC](https://discourse.vtk.org/t/self-intersections-from-extrusion/2919 "2020-03-31T19:52:26Z")

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I’m attempting to extrude and then make a solid voxel representation of a surface in VTK. The initial surface is well-behaved, not self-intersecting. The general pipeline is vtkLinearExtrusionFilter -\> vtkPolyDatatoImage…

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## [decreasing and increasing the points in vtp file](https://discourse.vtk.org/t/decreasing-and-increasing-the-points-in-vtp-file/2902)

<div class="topic-metadata">

**Author:** [@wal](https://discourse.vtk.org/u/wal)\
**Replies:** 5\
**Last updated:** [March 31, 2020, 6:28pm UTC](https://discourse.vtk.org/t/decreasing-and-increasing-the-points-in-vtp-file/2902 "2020-03-31T18:28:04Z")

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Hello, I am preparing data for a neural network, the input of my network will be a constant number of points with its coordinates and a scalar value. The problem with the vtp files is that they have a different number o…

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## [OpenGL state errors with QVTKOpenGLWidget and vtk8.2 on Render call](https://discourse.vtk.org/t/opengl-state-errors-with-qvtkopenglwidget-and-vtk8-2-on-render-call/2921)

<div class="topic-metadata">

**Author:** [@tchen87](https://discourse.vtk.org/u/tchen87)\
**Replies:** 6\
**Last updated:** [March 31, 2020, 4:58pm UTC](https://discourse.vtk.org/t/opengl-state-errors-with-qvtkopenglwidget-and-vtk8-2-on-render-call/2921 "2020-03-31T16:58:54Z")

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I have an stereo application utilizing QT and running well on VTK8.1 using QVTKWidget. However, when switching to VTK8.2, I see a number of VTK errors every time a call is made to vtkRenderer::Render() Here is the stack…

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## [BMP Reader](https://discourse.vtk.org/t/bmp-reader/2878)

<div class="topic-metadata">

**Author:** [@kalpathi](https://discourse.vtk.org/u/kalpathi)\
**Replies:** 15\
**Last updated:** [March 31, 2020, 1:23pm UTC](https://discourse.vtk.org/t/bmp-reader/2878 "2020-03-31T13:23:25Z")

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I havent used VTK in decades, so bear with me. It was a lot simpler C++ in the 90s! Or I am just too old! Trying to read a series of BMP images into a volume and isosurface it. Somehow its seg faulting. So I want to l…

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## [How to show gradient of isoSurface based on color.](https://discourse.vtk.org/t/how-to-show-gradient-of-isosurface-based-on-color/2874)

<div class="topic-metadata">

**Author:** [@ShaneKirkbride](https://discourse.vtk.org/u/ShaneKirkbride)\
**Replies:** 4\
**Last updated:** [March 31, 2020, 11:24am UTC](https://discourse.vtk.org/t/how-to-show-gradient-of-isosurface-based-on-color/2874 "2020-03-31T11:24:07Z")

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I’m trying to understand how I can render an isosurface and show it’s gradient using color. There are a few examples but it is unclear how to do this with an isosurface.

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## [Does VTK have any support to order triangles on a mesh?](https://discourse.vtk.org/t/does-vtk-have-any-support-to-order-triangles-on-a-mesh/2922)

<div class="topic-metadata">

**Author:** [@tdchen](https://discourse.vtk.org/u/tdchen)\
**Replies:** 0\
**Last updated:** [March 31, 2020, 5:04am UTC](https://discourse.vtk.org/t/does-vtk-have-any-support-to-order-triangles-on-a-mesh/2922 "2020-03-31T05:04:02Z")

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Hi vtkers. I need to make all triangles on a mesh having the same orientation, and even more to get the border of it. Does VTK have any support to this? Thank you in advance.

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## [vtksys documentation](https://discourse.vtk.org/t/vtksys-documentation/2912)

<div class="topic-metadata">

**Author:** [@mwestphal](https://discourse.vtk.org/u/mwestphal)\
**Replies:** 4\
**Last updated:** [March 31, 2020, 1:40am UTC](https://discourse.vtk.org/t/vtksys-documentation/2912 "2020-03-31T01:40:18Z")

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I do not seem to be able to find the documentation for vtksys. Does it live somewhere ? @ben.boeckel @brad.king

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## [OpenGL state errors with QVTKOpenGLWidget and vtk8.2](https://discourse.vtk.org/t/opengl-state-errors-with-qvtkopenglwidget-and-vtk8-2/539)

<div class="topic-metadata">

**Author:** [@geoffw](https://discourse.vtk.org/u/geoffw)\
**Replies:** 10\
**Last updated:** [March 31, 2020, 1:31am UTC](https://discourse.vtk.org/t/opengl-state-errors-with-qvtkopenglwidget-and-vtk8-2/539 "2020-03-31T01:31:15Z")

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Hi, We have an application based on Qt and Vtk. It runs well on VTK8.1 However, after upgrading to VTK8.2, we experience problems when we first call vtkRenderer::Render(). This call ultimately ends up calling vtkOpenGLS…

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## [isosurface related..](https://discourse.vtk.org/t/isosurface-related/2920)

<div class="topic-metadata">

**Author:** [@kalpathi](https://discourse.vtk.org/u/kalpathi)\
**Replies:** 0\
**Last updated:** [March 30, 2020, 8:34pm UTC](https://discourse.vtk.org/t/isosurface-related/2920 "2020-03-30T20:34:22Z")

</div>

If your data is coming from a multi-component image(say a bmp with r,gb) or volume, how do y you specify the component on which to extract the isoline/isosurface?

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## [vtk 9.0 rc1](https://discourse.vtk.org/t/vtk-9-0-rc1/2916)

<div class="topic-metadata">

**Author:** [@Leonid\_Dulman](https://discourse.vtk.org/u/Leonid_Dulman)\
**Replies:** 4\
**Last updated:** [March 30, 2020, 4:39pm UTC](https://discourse.vtk.org/t/vtk-9-0-rc1/2916 "2020-03-30T16:39:23Z")

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Hi to all I built VTK-9.0rc1 in windows and tested some demos I have got warning Generic Warning: In F:\\VTK-9.0.0\\Rendering\\OpenGL2\\vtkOpenGLPolyDataMapper.cxx, line 271 vtkOpenGLPolyDataMapper::GetVertexShaderCode w…

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## [QWidget and the vtkContextView?](https://discourse.vtk.org/t/qwidget-and-the-vtkcontextview/2907)

<div class="topic-metadata">

**Author:** [@wulicheng](https://discourse.vtk.org/u/wulicheng)\
**Replies:** 1\
**Last updated:** [March 30, 2020, 1:48am UTC](https://discourse.vtk.org/t/qwidget-and-the-vtkcontextview/2907 "2020-03-30T01:48:48Z")

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How can i integrate the vtkContextView withe the Qt’widget like QVTKＷＩｇｅｔ?

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## [Wrap enums as python's enum.Enum](https://discourse.vtk.org/t/wrap-enums-as-pythons-enum-enum/2909)

<div class="topic-metadata">

**Author:** [@imsodin](https://discourse.vtk.org/u/imsodin)\
**Replies:** 11\
**Last updated:** [March 29, 2020, 7:33pm UTC](https://discourse.vtk.org/t/wrap-enums-as-pythons-enum-enum/2909 "2020-03-29T19:33:28Z")

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I just reviewed a PR where a python project uses the FieldAssociation enum and had to re-create enum vtkDataObject::FieldAssociations, because the wrapped type isn’t actually a python enum (as in https://docs.python.org…

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## [vtkMarching Squares Example - dataset..](https://discourse.vtk.org/t/vtkmarching-squares-example-dataset/2897)

<div class="topic-metadata">

**Author:** [@kalpathi](https://discourse.vtk.org/u/kalpathi)\
**Replies:** 1\
**Last updated:** [March 28, 2020, 12:45pm UTC](https://discourse.vtk.org/t/vtkmarching-squares-example-dataset/2897 "2020-03-28T12:45:45Z")

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Could someone point me to the dataset (image) that was used in the following example: https://lorensen.github.io/VTKExamples/site/Cxx/Modelling/ContourTriangulator/ Or where you find datasets for many of the examples? …

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## [Plotting a bar diagram with more than 40.000 points is very slow](https://discourse.vtk.org/t/plotting-a-bar-diagram-with-more-than-40-000-points-is-very-slow/2889)

<div class="topic-metadata">

**Author:** [@MagnaBlandit](https://discourse.vtk.org/u/MagnaBlandit)\
**Replies:** 1\
**Last updated:** [March 26, 2020, 3:31pm UTC](https://discourse.vtk.org/t/plotting-a-bar-diagram-with-more-than-40-000-points-is-very-slow/2889 "2020-03-26T15:31:43Z")

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Hello, Iam trying to plot a 1D-Signal in a vtkChartXY. I have more than 40.000 points, which works fine with vtkChart.LINE and vtkChart.POINTS, but if I try to plot with vtkChart.BAR the program slows down significantl…

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## [random orientation, and location of objects in a bounding box](https://discourse.vtk.org/t/random-orientation-and-location-of-objects-in-a-bounding-box/2839)

<div class="topic-metadata">

**Author:** [@kayarre](https://discourse.vtk.org/u/kayarre)\
**Replies:** 4\
**Last updated:** [March 26, 2020, 10:35am UTC](https://discourse.vtk.org/t/random-orientation-and-location-of-objects-in-a-bounding-box/2839 "2020-03-26T10:35:41Z")

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I have a large set of PolyData shapes and I want to randomly sample from a list of them and place them in a bounded region in space, and don’t want them to overlap. They are generally the same size and all have zero orig…

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## [Surface Data on Structured Grid](https://discourse.vtk.org/t/surface-data-on-structured-grid/2887)

<div class="topic-metadata">

**Author:** [@B.S](https://discourse.vtk.org/u/B.S)\
**Replies:** 0\
**Last updated:** [March 26, 2020, 10:32am UTC](https://discourse.vtk.org/t/surface-data-on-structured-grid/2887 "2020-03-26T10:32:39Z")

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Looking for a document that discusses surface data for structured grids in detail. Any help would be appreciated. In particular, interested in visualizing surface data on the FACES of structured grid data (e.g. VTK-Hexa…

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## [VTK 9.0.0.rc1](https://discourse.vtk.org/t/vtk-9-0-0-rc1/2860)

<div class="topic-metadata">

**Author:** [@TJ\_Corona](https://discourse.vtk.org/u/TJ_Corona)\
**Replies:** 15\
**Last updated:** [March 25, 2020, 4:03pm UTC](https://discourse.vtk.org/t/vtk-9-0-0-rc1/2860 "2020-03-25T16:03:59Z")

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The VTK maintenance team is happy to announce that VTK 9.0 has entered the release candidate stage! You can find the source, data and documentation tarballs here. Take a look at the VTK wiki for a complete list of API …

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