# Development

**URL:** https://discourse.vtk.org/c/development/7.md?page=44

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

**Page:** 45

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## [vtkXRenderWindowInteractor: ProcessEvents does not work](https://discourse.vtk.org/t/vtkxrenderwindowinteractor-processevents-does-not-work/2969)

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**Author:** [@TomLKoller](https://discourse.vtk.org/u/TomLKoller)\
**Replies:** 6\
**Last updated:** [April 6, 2020, 6:00pm UTC](https://discourse.vtk.org/t/vtkxrenderwindowinteractor-processevents-does-not-work/2969 "2020-04-06T18:00:35Z")

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The ProcessEvents() method of vtkRenderWindowInteractor can be used to implement custom event loops. I used the method on a Ubuntu LTs 18.04 Machine with vtk 9. My setup worked when i called the Start() method but not …

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## [Development of a new PVTU writer to reduce the number of files](https://discourse.vtk.org/t/development-of-a-new-pvtu-writer-to-reduce-the-number-of-files/2926)

<div class="topic-metadata">

**Author:** [@GonzaloS](https://discourse.vtk.org/u/GonzaloS)\
**Replies:** 2\
**Last updated:** [April 6, 2020, 11:11am UTC](https://discourse.vtk.org/t/development-of-a-new-pvtu-writer-to-reduce-the-number-of-files/2926 "2020-04-06T11:11:22Z")

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Hi everyone, I know that a lot of people have problems when writing PVTU files using the vtkXMLPUnstructuredGridWriter object due to the fact that each processor writes a VTU file per PVTU output file. This means that …

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

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

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**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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## [png Android linking problem](https://discourse.vtk.org/t/png-android-linking-problem/1311)

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**Author:** [@hcwiley](https://discourse.vtk.org/u/hcwiley)\
**Replies:** 6\
**Last updated:** [March 24, 2020, 11:44am UTC](https://discourse.vtk.org/t/png-android-linking-problem/1311 "2020-03-24T11:44:26Z")

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There is a bug with linking to vtkpng after compiling for arm64-v8a with Android NDK 18b. I’m linking against vtk-8.2.0 arm64-v8a with another project that uses NEON and has flags specifying that. The linking error is: u…

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## [Release notes as part of merge requests](https://discourse.vtk.org/t/release-notes-as-part-of-merge-requests/2861)

<div class="topic-metadata">

**Author:** [@ben.boeckel](https://discourse.vtk.org/u/ben.boeckel)\
**Replies:** 0\
**Last updated:** [March 20, 2020, 5:44pm UTC](https://discourse.vtk.org/t/release-notes-as-part-of-merge-requests/2861 "2020-03-20T17:44:00Z")

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Hi developers, I’ve set up a directory Documentation/release/dev which is intended to contain snippets of release notes to add to topics for contribution. The goal of this is to help maintain release notes throughout th…

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## [Does anyone still use Xt for GUI development](https://discourse.vtk.org/t/does-anyone-still-use-xt-for-gui-development/2590)

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**Author:** [@ken-martin](https://discourse.vtk.org/u/ken-martin)\
**Replies:** 16\
**Last updated:** [March 20, 2020, 2:18pm UTC](https://discourse.vtk.org/t/does-anyone-still-use-xt-for-gui-development/2590 "2020-03-20T14:18:46Z")

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There is a chunk of Xt code in VTK and I’m wondering if people still use VTK within an Xt based app. Or has everything migrated to xcb or Qt etc?

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## [Does VTK offer some kind of key value variables saving functionality?](https://discourse.vtk.org/t/does-vtk-offer-some-kind-of-key-value-variables-saving-functionality/1950)

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**Author:** [@rai-sam](https://discourse.vtk.org/u/rai-sam)\
**Replies:** 6\
**Last updated:** [March 19, 2020, 2:22pm UTC](https://discourse.vtk.org/t/does-vtk-offer-some-kind-of-key-value-variables-saving-functionality/1950 "2020-03-19T14:22:30Z")

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Does VTK offer any kind of key value variable save and load functionality between run sessions? Like loading the render where you left last time? Usually called preferences. Saving settings is main target.

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## [How can I display orientation labels](https://discourse.vtk.org/t/how-can-i-display-orientation-labels/2835)

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**Author:** [@cocacc](https://discourse.vtk.org/u/cocacc)\
**Replies:** 1\
**Last updated:** [March 19, 2020, 1:40pm UTC](https://discourse.vtk.org/t/how-can-i-display-orientation-labels/2835 "2020-03-19T13:40:19Z")

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the orientation in the red box . i can‘t display.

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## [Translucent assemblies in 8.2.0](https://discourse.vtk.org/t/translucent-assemblies-in-8-2-0/419)

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**Author:** [@efahl](https://discourse.vtk.org/u/efahl)\
**Replies:** 16\
**Last updated:** [March 18, 2020, 12:25pm UTC](https://discourse.vtk.org/t/translucent-assemblies-in-8-2-0/419 "2020-03-18T12:25:39Z")

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I’m seeing a regression in 8.2.0 when rendering translucent objects inside a vtkAssembly. Here are four screen snaps of my test script’s output, top row is VTK 8.1.2, bottom row is VTK 8.2.0. Left column has actors adde…

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## [Problem with iOS example VolumeRender](https://discourse.vtk.org/t/problem-with-ios-example-volumerender/1482)

<div class="topic-metadata">

**Author:** [@wvalenzuela](https://discourse.vtk.org/u/wvalenzuela)\
**Replies:** 1\
**Last updated:** [March 17, 2020, 2:37pm UTC](https://discourse.vtk.org/t/problem-with-ios-example-volumerender/1482 "2020-03-17T14:37:37Z")

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Dear All, I compiled the VTK for iOS 12.4, and all the examples from Example/iOS/ works really well except the VolumeRender. VTK/Examples/iOS/VolumeRender for iOS on iPhone XR didn’t show nothing only the background. T…

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## [How to build VTK with vtkParallelTimer](https://discourse.vtk.org/t/how-to-build-vtk-with-vtkparalleltimer/2228)

<div class="topic-metadata">

**Author:** [@toddy](https://discourse.vtk.org/u/toddy)\
**Replies:** 6\
**Last updated:** [March 16, 2020, 2:59pm UTC](https://discourse.vtk.org/t/how-to-build-vtk-with-vtkparalleltimer/2228 "2020-03-16T14:59:27Z")

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Could someone please explain how to get VTK to include vtkParallelTimer? I’ve tried building with VTK\_USE\_MPI and adding a BOOL entry to CMake with VTK\_RENDERINGPARALLELLIC\_SURFACELICPAINTER\_TIMER = ON and VTK\_RENDER…

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## [vtkMFCWindow in v8.2.0 for Win32 GUI support has an error handling message WM\_MOUSEWHEEL](https://discourse.vtk.org/t/vtkmfcwindow-in-v8-2-0-for-win32-gui-support-has-an-error-handling-message-wm-mousewheel/1921)

<div class="topic-metadata">

**Author:** [@Stilles](https://discourse.vtk.org/u/Stilles)\
**Replies:** 1\
**Last updated:** [March 16, 2020, 2:30pm UTC](https://discourse.vtk.org/t/vtkmfcwindow-in-v8-2-0-for-win32-gui-support-has-an-error-handling-message-wm-mousewheel/1921 "2020-03-16T14:30:58Z")

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Finally, I get here to report this error and hope some one can fix it in later versions. Here is piece code handling WM\_MOUSEWHEEL in vtkMFCWindow.cxx: BOOL vtkMFCWindow::OnMouseWheel(UINT nFlags, short zDelta, CPoin…

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## [Getting Python version](https://discourse.vtk.org/t/getting-python-version/1563)

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**Author:** [@Ron84](https://discourse.vtk.org/u/Ron84)\
**Replies:** 2\
**Last updated:** [March 16, 2020, 2:21pm UTC](https://discourse.vtk.org/t/getting-python-version/1563 "2020-03-16T14:21:17Z")

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Another question for you @dgobbi. How can I detect VTKs Python version? I tried this: execute\_process(COMMAND "${\_vtk}/bin/vtkpython" -c "import sys; sys.stdout.write('.'.join(map(str, sys.version\_info\[:2\])))" OUTPUT\_…

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## [CloudFlare zlib?](https://discourse.vtk.org/t/cloudflare-zlib/2330)

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**Author:** [@dzenanz](https://discourse.vtk.org/u/dzenanz)\
**Replies:** 19\
**Last updated:** [March 16, 2020, 12:55pm UTC](https://discourse.vtk.org/t/cloudflare-zlib/2330 "2020-03-16T12:55:49Z")

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The ITK community has been looking for ways to improve image compression speeds. A low hanging fruit is using CloudFlare fork of zlib, at least as a default option. But as ITK and VTK share CMake-ification of zlib, I wan…

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## [vtkImagePlaneWidget default lookup table is an S-curve ramp](https://discourse.vtk.org/t/vtkimageplanewidget-default-lookup-table-is-an-s-curve-ramp/2818)

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**Author:** [@simonesneault](https://discourse.vtk.org/u/simonesneault)\
**Replies:** 0\
**Last updated:** [March 13, 2020, 2:02pm UTC](https://discourse.vtk.org/t/vtkimageplanewidget-default-lookup-table-is-an-s-curve-ramp/2818 "2020-03-13T14:02:42Z")

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Hello, just wanted to share that it looks strange (to me) to use an S-Curve ramp as a default in the vtkImagePlaneWidget … When setting a window level from outside, we don’t get the same image than most of the dicom vie…

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## [Find normal vector from a point cloud](https://discourse.vtk.org/t/find-normal-vector-from-a-point-cloud/2803)

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**Author:** [@smlm94](https://discourse.vtk.org/u/smlm94)\
**Replies:** 0\
**Last updated:** [March 11, 2020, 9:58am UTC](https://discourse.vtk.org/t/find-normal-vector-from-a-point-cloud/2803 "2020-03-11T09:58:55Z")

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Hi, experts, 1)I would like to ask about how can I mark a specific normal vector on a specific XYZ coordinate from a PLY point cloud file? 2)How to convert normal vector to a component with x rotation, y rotation and z…

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## [VTK8.2: Color buffer depth](https://discourse.vtk.org/t/vtk8-2-color-buffer-depth/402)

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**Author:** [@hmxhiu](https://discourse.vtk.org/u/hmxhiu)\
**Replies:** 7\
**Last updated:** [March 6, 2020, 5:27pm UTC](https://discourse.vtk.org/t/vtk8-2-color-buffer-depth/402 "2020-03-06T17:27:44Z")

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I’m currently running VTK8.2 and python3.7 on the new Mac Mini 2018. However, the vtkPropPicker throw the following error: ERROR: In /VTK 8.2.0/Rendering/Core/vtkHardwareSelector.cxx, line 288 vtkOpenGLHardwareSelecto…

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## [Building errors](https://discourse.vtk.org/t/building-errors/2746)

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**Author:** [@Nina](https://discourse.vtk.org/u/Nina)\
**Replies:** 3\
**Last updated:** [March 3, 2020, 3:45pm UTC](https://discourse.vtk.org/t/building-errors/2746 "2020-03-03T15:45:40Z")

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Hi, I tried to re-implement the vtkMPUReconstruction using the slicer3D. The 3D Slicer is compiled without errors. but when I compile the method I get errors like this: LNK2001 unresolved external symbol “public: v…

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## [python version of the Frenet frame](https://discourse.vtk.org/t/python-version-of-the-frenet-frame/2747)

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**Author:** [@Olicr](https://discourse.vtk.org/u/Olicr)\
**Replies:** 5\
**Last updated:** [March 4, 2020, 6:52pm UTC](https://discourse.vtk.org/t/python-version-of-the-frenet-frame/2747 "2020-03-04T18:52:36Z")

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Dear VTK experts, I know there is a C++ implementation of the Frenet frame and a demo is available in the following link: https://cmake.org/Wiki/VTK/Examples/Cxx/Remote/FrenetSerretFrame But I can’t seem to find a ver…

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## [Surface and volume rendering in the same render](https://discourse.vtk.org/t/surface-and-volume-rendering-in-the-same-render/2717)

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**Author:** [@snow](https://discourse.vtk.org/u/snow)\
**Replies:** 3\
**Last updated:** [March 3, 2020, 8:35am UTC](https://discourse.vtk.org/t/surface-and-volume-rendering-in-the-same-render/2717 "2020-03-03T08:35:26Z")

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I create a vtkpolydata and a vtkImagedata ,add a vtkActor and vtkVolume to the same render,the vtkpolydata is a closed surface, and intersect with the volume . when I set the vtkActor opacity to 1, actor-\>GetProperty…

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## [libexpat 2.2.6 version presents some vulnerabilities](https://discourse.vtk.org/t/libexpat-2-2-6-version-presents-some-vulnerabilities/2697)

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**Author:** [@simonesneault](https://discourse.vtk.org/u/simonesneault)\
**Replies:** 2\
**Last updated:** [February 28, 2020, 2:38pm UTC](https://discourse.vtk.org/t/libexpat-2-2-6-version-presents-some-vulnerabilities/2697 "2020-02-28T14:38:37Z")

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Hi All, The embedded version of libexpat (2.2.6) in VTK presents some vulnerabilities : https://nvd.nist.gov/vuln/detail/CVE-2019-15903 https://nvd.nist.gov/vuln/detail/CVE-2018-20843 Would it be possible to bump the…

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## [building libs for r/w vtk and xdmf geometry formats](https://discourse.vtk.org/t/building-libs-for-r-w-vtk-and-xdmf-geometry-formats/2724)

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**Author:** [@kcris](https://discourse.vtk.org/u/kcris)\
**Replies:** 0\
**Last updated:** [February 28, 2020, 2:07pm UTC](https://discourse.vtk.org/t/building-libs-for-r-w-vtk-and-xdmf-geometry-formats/2724 "2020-02-28T14:07:53Z")

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Hi, I plan to use vtk libraries for reading/writing various vtk geometry objects (using vtk text formats, xdms formats). Vtk sourcecode is huge and I am a bit lost, there are literally hundreds of modules. And I am ju…

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## [Using vtkImagePermute on vtkImageData with multiple scalars](https://discourse.vtk.org/t/using-vtkimagepermute-on-vtkimagedata-with-multiple-scalars/2714)

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**Author:** [@Patrick\_Avery](https://discourse.vtk.org/u/Patrick_Avery)\
**Replies:** 3\
**Last updated:** [February 28, 2020, 12:34am UTC](https://discourse.vtk.org/t/using-vtkimagepermute-on-vtkimagedata-with-multiple-scalars/2714 "2020-02-28T00:34:32Z")

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We have been using vtkImagePermute to swap two axes on vtkImageData in Tomviz. We have also recently been adding support for the vtkImageData to have multiple scalars associated with it (i. e., image-\>GetPointData()-\>Get…

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## [Creating a MR requires to be a VTK "Developer"](https://discourse.vtk.org/t/creating-a-mr-requires-to-be-a-vtk-developer/2705)

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**Author:** [@mwestphal](https://discourse.vtk.org/u/mwestphal)\
**Replies:** 3\
**Last updated:** [February 27, 2020, 7:50am UTC](https://discourse.vtk.org/t/creating-a-mr-requires-to-be-a-vtk-developer/2705 "2020-02-27T07:50:08Z")

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It looks like it is required to be part of the VTK group at developer level to be able to create a MR. Is that intended ? The develop.md does not mention it at all. @utkarshayachit @brad.king @cory.quammen

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## [Rendering problems with per-cell colored surfaces on Surface 7](https://discourse.vtk.org/t/rendering-problems-with-per-cell-colored-surfaces-on-surface-7/2698)

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**Author:** [@nenad-vujicic](https://discourse.vtk.org/u/nenad-vujicic)\
**Replies:** 7\
**Last updated:** [February 26, 2020, 2:33pm UTC](https://discourse.vtk.org/t/rendering-problems-with-per-cell-colored-surfaces-on-surface-7/2698 "2020-02-26T14:33:25Z")

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Hello everyone, I’m having problems with using my VTK + QT application and per-cell coloring on Surface 7 tablet. I use VTK version (a5f938b2fdfefa522439065e040cb42f65d88444) which was used btw for the latest ParaView r…

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## [VTK 9.0](https://discourse.vtk.org/t/vtk-9-0/2691)

<div class="topic-metadata">

**Author:** [@TJ\_Corona](https://discourse.vtk.org/u/TJ_Corona)\
**Replies:** 3\
**Last updated:** [February 25, 2020, 2:57pm UTC](https://discourse.vtk.org/t/vtk-9-0/2691 "2020-02-25T14:57:43Z")

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Hi, Does anyone have work in progress that should delay the branch point for v9.0.0? If so, please add the v9.0.0\_rc1 milestone on any relevant merge requests and mention @ben.boeckel @TJ\_Corona so they can be more e…

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