# Support

**URL:** https://discourse.vtk.org/c/support/6.md?page=12

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

**Page:** 13

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## [Interested in options in drawing 1 bit per pixel images from slice geometry](https://discourse.vtk.org/t/interested-in-options-in-drawing-1-bit-per-pixel-images-from-slice-geometry/15343)

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**Author:** [@citrit](https://discourse.vtk.org/u/citrit)\
**Replies:** 1\
**Last updated:** [March 6, 2025, 7:02pm UTC](https://discourse.vtk.org/t/interested-in-options-in-drawing-1-bit-per-pixel-images-from-slice-geometry/15343 "2025-03-06T19:02:27Z")

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I am writing code to generate images from slice data at very high resolution. These images will be written to files using a 1 bit per pixel format. I am able to slice the geometry easily but need a good pipeline to solve…

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## [How to set custom shader with VTK 8.1(C++)](https://discourse.vtk.org/t/how-to-set-custom-shader-with-vtk-8-1-c/15122)

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**Author:** [@1078586743](https://discourse.vtk.org/u/1078586743)\
**Replies:** 7\
**Last updated:** [March 6, 2025, 1:46pm UTC](https://discourse.vtk.org/t/how-to-set-custom-shader-with-vtk-8-1-c/15122 "2025-03-06T13:46:20Z")

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Hi,everyone How can i set custom shader with VTK8.1? I know it’s probably using vtkShaderProgram,but i can’t find any example. Could you please provide insights for achieving this? Your guidance would be greatly appr…

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## [Rendering changes between 9.2.6 and 9.3.0?](https://discourse.vtk.org/t/rendering-changes-between-9-2-6-and-9-3-0/15323)

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**Author:** [@raungst](https://discourse.vtk.org/u/raungst)\
**Replies:** 4\
**Last updated:** [March 5, 2025, 4:08pm UTC](https://discourse.vtk.org/t/rendering-changes-between-9-2-6-and-9-3-0/15323 "2025-03-05T16:08:10Z")

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I have a Python / PySide6 / VTK application that renders unstructured grids and I’ve noticed a change of behavior when using 9.2.6 and 9.3.0 and I’m trying to track down what changed and how to fix it. In 9.2.6, I can l…

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## [OpenXR Problem](https://discourse.vtk.org/t/openxr-problem/14748)

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**Author:** [@zist8888](https://discourse.vtk.org/u/zist8888)\
**Replies:** 7\
**Last updated:** [March 5, 2025, 2:15pm UTC](https://discourse.vtk.org/t/openxr-problem/14748 "2025-03-05T14:15:21Z")

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I got vtk9.4.0.rc2,compile and get error as this,someone can help! vtk9.3.0 is ok. “/MANIFESTDEPENDENCY:type=‘win32’ name=‘Microsoft.Windows.Common-Controls’ version=‘6.0.0.0’ publicKeyToken=‘6595b64144ccf1df’ language=…

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## [How to draw multiple vtkImageTracerWidget using left mouse button through interaction?](https://discourse.vtk.org/t/how-to-draw-multiple-vtkimagetracerwidget-using-left-mouse-button-through-interaction/15334)

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**Author:** [@SeanHan](https://discourse.vtk.org/u/SeanHan)\
**Replies:** 0\
**Last updated:** [March 4, 2025, 6:24am UTC](https://discourse.vtk.org/t/how-to-draw-multiple-vtkimagetracerwidget-using-left-mouse-button-through-interaction/15334 "2025-03-04T06:24:12Z")

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A single vtkImageTracerWidget is easy to draw, after that left down button event on the view port will be blocked by the 1st vtkImageTracerWidget drawn on the view. Who can tell me how to modify vtkImageTracerWidget or h…

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## [In VTK+WASM, how do I make the camera zoom on right click?](https://discourse.vtk.org/t/in-vtk-wasm-how-do-i-make-the-camera-zoom-on-right-click/15338)

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**Author:** [@uv382](https://discourse.vtk.org/u/uv382)\
**Replies:** 1\
**Last updated:** [March 5, 2025, 1:46am UTC](https://discourse.vtk.org/t/in-vtk-wasm-how-do-i-make-the-camera-zoom-on-right-click/15338 "2025-03-05T01:46:09Z")

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Normally in VTK, if you wanted to modify what each mouse button does, you would create a subclass of vtkInteractorStyle with all your custom events described. For example, in Python, if you wanted the camera to zoom eve…

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## [Ray Box intersection](https://discourse.vtk.org/t/ray-box-intersection/15243)

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**Author:** [@ferdymercury](https://discourse.vtk.org/u/ferdymercury)\
**Replies:** 3\
**Last updated:** [March 4, 2025, 8:39am UTC](https://discourse.vtk.org/t/ray-box-intersection/15243 "2025-03-04T08:39:54Z")

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Dear experts, I wanted to ask if there is an optimized code within VTK that returns the 1D coordinate of the intersection of a directional ray within a box, with the box itself. Something like explained here: https://p…

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## [In the directory ThirdParty\\glad of VTK9.4, there is no gles.h file. Does vtk9.4 support gles?](https://discourse.vtk.org/t/in-the-directory-thirdparty-glad-of-vtk9-4-there-is-no-gles-h-file-does-vtk9-4-support-gles/14988)

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**Author:** [@Ynnnnnn](https://discourse.vtk.org/u/Ynnnnnn)\
**Replies:** 2\
**Last updated:** [March 4, 2025, 2:25am UTC](https://discourse.vtk.org/t/in-the-directory-thirdparty-glad-of-vtk9-4-there-is-no-gles-h-file-does-vtk9-4-support-gles/14988 "2025-03-04T02:25:14Z")

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In the directory ThirdParty\\glad of VTK9.4, there is no gles.h file. Does vtk9.4 support gles?

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## [When compiling VTK 9.4.1 on Linux, there is no prompt for the VTK\_OPENGL\_USE\_GLES option, and there are other compilation errors.](https://discourse.vtk.org/t/when-compiling-vtk-9-4-1-on-linux-there-is-no-prompt-for-the-vtk-opengl-use-gles-option-and-there-are-other-compilation-errors/15296)

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**Author:** [@Ynnnnnn](https://discourse.vtk.org/u/Ynnnnnn)\
**Replies:** 3\
**Last updated:** [March 4, 2025, 2:19am UTC](https://discourse.vtk.org/t/when-compiling-vtk-9-4-1-on-linux-there-is-no-prompt-for-the-vtk-opengl-use-gles-option-and-there-are-other-compilation-errors/15296 "2025-03-04T02:19:42Z")

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Compiling VTK 9.4.0 works fine. When compiling VTK 9.4.1 with CMake on Linux, there is no prompt for the VTK\_OPENGL\_USE\_GLES option. After adding it manually, there are many errors. During compilation, VTK\_OPENGL\_HAS\_E…

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## [create python .dist-info folder without wheel build](https://discourse.vtk.org/t/create-python-dist-info-folder-without-wheel-build/14814)

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**Author:** [@JonathanS](https://discourse.vtk.org/u/JonathanS)\
**Replies:** 2\
**Last updated:** [March 3, 2025, 11:07pm UTC](https://discourse.vtk.org/t/create-python-dist-info-folder-without-wheel-build/14814 "2025-03-03T23:07:06Z")

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We include vtk in Macports with an option to wrap python. This “standard” install includes the c++ libraries along with the python wrappers, but the .dist-info folder is not created or installed. When searching for a sol…

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## [Best way to implement VTK 9.1 with Qt6 using QML (and Qt Quick...)](https://discourse.vtk.org/t/best-way-to-implement-vtk-9-1-with-qt6-using-qml-and-qt-quick/6958)

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**Author:** [@Julienchz](https://discourse.vtk.org/u/Julienchz)\
**Replies:** 11\
**Last updated:** [March 3, 2025, 11:06pm UTC](https://discourse.vtk.org/t/best-way-to-implement-vtk-9-1-with-qt6-using-qml-and-qt-quick/6958 "2025-03-03T23:06:05Z")

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Hello everyone, I want to implent VTK 9.1 with Qt6 in a QtQuick project, whats is the best way to proceed ? Qt6 suggests using QRhi and QSGMaterialShader for handling graphical APIs (for better abstraction) like OpenGl…

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## [Separate builds for core and python wrappers](https://discourse.vtk.org/t/separate-builds-for-core-and-python-wrappers/14937)

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**Author:** [@Dave-Allured](https://discourse.vtk.org/u/Dave-Allured)\
**Replies:** 3\
**Last updated:** [March 3, 2025, 11:01pm UTC](https://discourse.vtk.org/t/separate-builds-for-core-and-python-wrappers/14937 "2025-03-03T23:01:19Z")

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I need to build python wrappers separately from the VTK core, in order to support multiple python versions. I can set VTK\_WRAP\_PYTHON=OFF to build core only. Is there a way to build wrappers only, on top of a previous …

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## ["Could NOT find MPI (missing: MPI\_C\_FOUND C)" CMake error](https://discourse.vtk.org/t/could-not-find-mpi-missing-mpi-c-found-c-cmake-error/15048)

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**Author:** [@Michele\_Pellegrino](https://discourse.vtk.org/u/Michele_Pellegrino)\
**Replies:** 10\
**Last updated:** [March 3, 2025, 10:33pm UTC](https://discourse.vtk.org/t/could-not-find-mpi-missing-mpi-c-found-c-cmake-error/15048 "2025-03-03T22:33:41Z")

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Hi, I am trying to build LAMMPS with the VTK package. I am getting this error when running cmake: CMake Error at /usr/local/share/cmake-3.31/Modules/FindPackageHandleStandardArgs.cmake:233 (message): Could NOT find M…

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## [Crash when configuration conflict (library debug & vtk release)](https://discourse.vtk.org/t/crash-when-configuration-conflict-library-debug-vtk-release/14984)

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**Author:** [@pcristini](https://discourse.vtk.org/u/pcristini)\
**Replies:** 2\
**Last updated:** [March 3, 2025, 9:55pm UTC](https://discourse.vtk.org/t/crash-when-configuration-conflict-library-debug-vtk-release/14984 "2025-03-03T21:55:49Z")

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I’m running into an odd error that I can’t seem to figure out the reason behind. With the following code I get a crash when compiling release mode, but it runs totally fine in debug mode. I’m working with vtk 9.2 librar…

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## [Using VTK9.4 to read files exceeding 2GB, displaying an exception](https://discourse.vtk.org/t/using-vtk9-4-to-read-files-exceeding-2gb-displaying-an-exception/14898)

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**Author:** [@clg](https://discourse.vtk.org/u/clg)\
**Replies:** 1\
**Last updated:** [March 3, 2025, 9:31pm UTC](https://discourse.vtk.org/t/using-vtk9-4-to-read-files-exceeding-2gb-displaying-an-exception/14898 "2025-03-03T21:31:02Z")

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imageReaderTemp-\>SetFileName(GlobalFunc::TString2MultiByteString(rawPath).c\_str()); = imageReaderTemp-\>SetDataScalarTypeToShort(); = imageReaderTemp-\>SetFileDimensionality(3…

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## [QVTKOpenGLNativeWidget in QGraphicsView Causing White Screen in Qt 6.5.6](https://discourse.vtk.org/t/qvtkopenglnativewidget-in-qgraphicsview-causing-white-screen-in-qt-6-5-6/14764)

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**Author:** [@Manjunath\_AV](https://discourse.vtk.org/u/Manjunath_AV)\
**Replies:** 1\
**Last updated:** [March 3, 2025, 9:26pm UTC](https://discourse.vtk.org/t/qvtkopenglnativewidget-in-qgraphicsview-causing-white-screen-in-qt-6-5-6/14764 "2025-03-03T21:26:50Z")

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We are currently in the process of porting our project from Qt 5.15 to Qt 6.5.6. In Qt 5.15, we were successfully using QGLWidget in conjunction with QGraphicsView. However, after the upgrade to Qt 6, we have replaced QG…

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## [VTK-7.1.1 can't build from Ubuntu 22.04.1 LTS(aarch64)](https://discourse.vtk.org/t/vtk-7-1-1-cant-build-from-ubuntu-22-04-1-lts-aarch64/10381)

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**Author:** [@Liusd123456](https://discourse.vtk.org/u/Liusd123456)\
**Replies:** 6\
**Last updated:** [March 3, 2025, 2:56pm UTC](https://discourse.vtk.org/t/vtk-7-1-1-cant-build-from-ubuntu-22-04-1-lts-aarch64/10381 "2025-03-03T14:56:42Z")

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hi, environment:Ubuntu 22.04.1 LTS(aarch64),GNU Make 4.3(aarch64-unknown-linux-gnu), gcc (Ubuntu 11.2.0-19ubuntu1) 11.2.0. make report errors: \[ 33%\] Linking CXX shared library …/…/lib/libvtkCommonSystem-7.1.so \[ 33%…

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## [vtkParametricSpline not smooth](https://discourse.vtk.org/t/vtkparametricspline-not-smooth/15139)

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**Author:** [@liuzhongshu](https://discourse.vtk.org/u/liuzhongshu)\
**Replies:** 1\
**Last updated:** [February 27, 2025, 7:03am UTC](https://discourse.vtk.org/t/vtkparametricspline-not-smooth/15139 "2025-02-27T07:03:43Z")

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I am using vtkParametricSpline and vtkParametricFunctionSource to draw a curve, but the line is not smooth. import vtk points = vtk.vtkPoints() points.InsertNextPoint(0.0, 0.0, 0.0) points.InsertNextPoint(1.0, 1.0, 0.0…

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## [vtkDecimatePolylineFilter not reducing the number of points](https://discourse.vtk.org/t/vtkdecimatepolylinefilter-not-reducing-the-number-of-points/14334)

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**Author:** [@Antoine\_Legouhy](https://discourse.vtk.org/u/Antoine_Legouhy)\
**Replies:** 5\
**Last updated:** [February 26, 2025, 9:21pm UTC](https://discourse.vtk.org/t/vtkdecimatepolylinefilter-not-reducing-the-number-of-points/14334 "2025-02-26T21:21:29Z")

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Using vtk for python, when using vtkDecimatePolylineFilter, the output has the same number of points (and lines) as the input. Here below a minimal example supposed decimate from 30 to 10 points (target reduction of 0.6…

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## [Creating venv virtual environment with vtkpython ?](https://discourse.vtk.org/t/creating-venv-virtual-environment-with-vtkpython/15317)

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**Author:** [@Nicholas\_Yue](https://discourse.vtk.org/u/Nicholas_Yue)\
**Replies:** 2\
**Last updated:** [February 26, 2025, 4:09pm UTC](https://discourse.vtk.org/t/creating-venv-virtual-environment-with-vtkpython/15317 "2025-02-26T16:09:44Z")

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I wish to create a VTK python virtual environment. I tried nyue@compute1:~/temp$ which vtkpython /home/nyue/systems/VTK/9.4.1-static/bin/vtkpython nyue@compute1:~/temp$ vtkpython -m venv .venv Error: \[Errno 2\] No such …

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## [Can't change the font size and style of Legend labels for vtkChartLegend()](https://discourse.vtk.org/t/cant-change-the-font-size-and-style-of-legend-labels-for-vtkchartlegend/15302)

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**Author:** [@roy](https://discourse.vtk.org/u/roy)\
**Replies:** 0\
**Last updated:** [February 24, 2025, 10:15am UTC](https://discourse.vtk.org/t/cant-change-the-font-size-and-style-of-legend-labels-for-vtkchartlegend/15302 "2025-02-24T10:15:58Z")

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I am implementing a 2d Histogram in VTK by following the example https://examples.vtk.org/site/Cxx/Plotting/Histogram2D/ . To change the font size and style of the legend labels after setting the transfer function I tri…

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## [Does VTK have an implementation of the SurfaceNets algorithm for a continuous scalar field?](https://discourse.vtk.org/t/does-vtk-have-an-implementation-of-the-surfacenets-algorithm-for-a-continuous-scalar-field/15300)

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**Author:** [@1358361259a](https://discourse.vtk.org/u/1358361259a)\
**Replies:** 2\
**Last updated:** [February 23, 2025, 4:58pm UTC](https://discourse.vtk.org/t/does-vtk-have-an-implementation-of-the-surfacenets-algorithm-for-a-continuous-scalar-field/15300 "2025-02-23T16:58:39Z")

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I am looking for a fast and high-quality mesh extraction algorithm for isosurfaces. I came across this paper: Improving Triangle Mesh Quality with SurfaceNets I then discovered vtkSurfaceNets3D, but this class seems to…

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## [Render Cell Scalars from vtkXMLPolyData?](https://discourse.vtk.org/t/render-cell-scalars-from-vtkxmlpolydata/15282)

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**Author:** [@rexthor](https://discourse.vtk.org/u/rexthor)\
**Replies:** 15\
**Last updated:** [February 21, 2025, 8:31pm UTC](https://discourse.vtk.org/t/render-cell-scalars-from-vtkxmlpolydata/15282 "2025-02-21T20:31:19Z")

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Seems like this should be simple? I most often read files and write files, and then use ParaView to examine my data - but this time I am trying to render it. I have a collection of vtkXMLPolyData files that have three C…

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## [Docker error when trying to run on a mac](https://discourse.vtk.org/t/docker-error-when-trying-to-run-on-a-mac/15286)

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**Author:** [@Gaston\_Avto](https://discourse.vtk.org/u/Gaston_Avto)\
**Replies:** 5\
**Last updated:** [February 21, 2025, 10:09am UTC](https://discourse.vtk.org/t/docker-error-when-trying-to-run-on-a-mac/15286 "2025-02-21T10:09:10Z")

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Hi! I am trying to a run a simple docker container for a trame app on mac and I am met with this error: 2.855 ERROR: Could not find a version that satisfies the requirement vtk-egl (from versions: none) 3.784 ERROR: N…

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## [How to Align the Vertex from VS with gl\_FragCoord in FS of VTK Shader?](https://discourse.vtk.org/t/how-to-align-the-vertex-from-vs-with-gl-fragcoord-in-fs-of-vtk-shader/15284)

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**Author:** [@WailmerPail](https://discourse.vtk.org/u/WailmerPail)\
**Replies:** 0\
**Last updated:** [February 20, 2025, 5:08am UTC](https://discourse.vtk.org/t/how-to-align-the-vertex-from-vs-with-gl-fragcoord-in-fs-of-vtk-shader/15284 "2025-02-20T05:08:43Z")

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Hi teams, I’m working with VTK shaders and I have a question regarding passing computed vertex positions from the vertex shader to the fragment shader and aligning them with the gl\_FragCoord coordinate system. In the v…

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## [How to measure CT values within the region of interest on MPR images？](https://discourse.vtk.org/t/how-to-measure-ct-values-within-the-region-of-interest-on-mpr-images/15114)

<div class="topic-metadata">

**Author:** [@SeanHan](https://discourse.vtk.org/u/SeanHan)\
**Replies:** 12\
**Last updated:** [February 19, 2025, 9:54am UTC](https://discourse.vtk.org/t/how-to-measure-ct-values-within-the-region-of-interest-on-mpr-images/15114 "2025-02-19T09:54:14Z")

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Hello， How to measure CT values within the region of interest on MPR images. Such as maximum value, minimum value, mean square deviation, etc. Any reply will be appreciated.

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## [vtkDistanceWidget and its text](https://discourse.vtk.org/t/vtkdistancewidget-and-its-text/15204)

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**Author:** [@Andrea\_Gavana](https://discourse.vtk.org/u/Andrea_Gavana)\
**Replies:** 1\
**Last updated:** [February 17, 2025, 9:52pm UTC](https://discourse.vtk.org/t/vtkdistancewidget-and-its-text/15204 "2025-02-17T21:52:33Z")

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Dear VTK users, Long time no see :blush:. I’ve restarted using VTK in Python and I’m currently fighting with vtkDistanceWidget… I have linked it to a vtkDistanceRepresentation2D and I’m trying to use it in a 3D window …

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## [Excluding Drawn Contour Area When Using vtkLinearExtrusionFilter](https://discourse.vtk.org/t/excluding-drawn-contour-area-when-using-vtklinearextrusionfilter/15248)

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**Author:** [@christeen](https://discourse.vtk.org/u/christeen)\
**Replies:** 3\
**Last updated:** [February 14, 2025, 8:23am UTC](https://discourse.vtk.org/t/excluding-drawn-contour-area-when-using-vtklinearextrusionfilter/15248 "2025-02-14T08:23:18Z")

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I am using vtkContourWidget to use contour drawing over an STL actor. Next, I use vtkClipPolyData to extract the region outside the drawn contour. Then, I apply vtkLinearExtrusionFilter to generate a 3 mm thick regio…

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## [Are there any lighter, well-engineered c++ & QT open-source examples that can achieve data reading, editing, etc.?](https://discourse.vtk.org/t/are-there-any-lighter-well-engineered-c-qt-open-source-examples-that-can-achieve-data-reading-editing-etc/15250)

<div class="topic-metadata">

**Author:** [@Ynnnnnn](https://discourse.vtk.org/u/Ynnnnnn)\
**Replies:** 2\
**Last updated:** [February 12, 2025, 9:34am UTC](https://discourse.vtk.org/t/are-there-any-lighter-well-engineered-c-qt-open-source-examples-that-can-achieve-data-reading-editing-etc/15250 "2025-02-12T09:34:29Z")

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The existing VTK examples are all implemented in a single file. They do not demonstrate how to organize data or how to engineer the project. Are there any lighter, well-engineered c++ & QT open-source examples that can…

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## [Survey about updating VTK's minimal C++ standard version](https://discourse.vtk.org/t/survey-about-updating-vtks-minimal-c-standard-version/12763)

<div class="topic-metadata">

**Author:** [@cory.quammen](https://discourse.vtk.org/u/cory.quammen)\
**Replies:** 17\
**Last updated:** [February 11, 2025, 8:28pm UTC](https://discourse.vtk.org/t/survey-about-updating-vtks-minimal-c-standard-version/12763 "2025-02-11T20:28:21Z")

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Hello VTK community! VTK is a widely used library for visualization. As such, it has needed to support many different compilers, including gcc 4.8.5. As a result, VTK has been limited to using only features available in…

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