# Latest

**URL:** https://discourse.vtk.org/latest.md?page=222

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

**Page:** 223

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## [Using a matrix to color 3-D surface plot](https://discourse.vtk.org/t/using-a-matrix-to-color-3-d-surface-plot/2783)

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**Author:** [@ATL\_Flaneur](https://discourse.vtk.org/u/ATL_Flaneur)\
**Replies:** 0\
**Last updated:** [March 9, 2020, 7:27pm UTC](https://discourse.vtk.org/t/using-a-matrix-to-color-3-d-surface-plot/2783 "2020-03-09T19:27:03Z")

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I’m learning VTK and trying to create an interactive 3-D surface plot where I have one 2-D array of scalars that gives the surface elevation and another 2-D array of RGB tuples that gives the color for that part of the s…

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## [Read a multi-frames DICOM dataset with VTK](https://discourse.vtk.org/t/read-a-multi-frames-dicom-dataset-with-vtk/2777)

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**Author:** [@RomyM](https://discourse.vtk.org/u/RomyM)\
**Replies:** 3\
**Last updated:** [March 9, 2020, 2:53pm UTC](https://discourse.vtk.org/t/read-a-multi-frames-dicom-dataset-with-vtk/2777 "2020-03-09T14:53:21Z")

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Hello, With vtkDICOMImageReader() I tried to read a single 3D DICOM file. Unfortunately, this reader does not handle multi-frames DICOM datasets (as documented https://vtk.org/doc/nightly/html/classvtkDICOMImageReader.h…

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## [ParaView 5.8 Features Free Webinar](https://discourse.vtk.org/t/paraview-5-8-features-free-webinar/2696)

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**Author:** [@mwestphal](https://discourse.vtk.org/u/mwestphal)\
**Replies:** 3\
**Last updated:** [March 9, 2020, 9:22am UTC](https://discourse.vtk.org/t/paraview-5-8-features-free-webinar/2696 "2020-03-09T09:22:24Z")

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Are you ready to join Kitware’s ParaView free Webinar ? These first two sessions will happen in March and be focused on ParaView 5.8 new features. During these 1 hour sessions, you will not only be able to follow our e…

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## [Volume rendering Error](https://discourse.vtk.org/t/volume-rendering-error/2690)

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**Author:** [@Alex1](https://discourse.vtk.org/u/Alex1)\
**Replies:** 5\
**Last updated:** [March 7, 2020, 10:28am UTC](https://discourse.vtk.org/t/volume-rendering-error/2690 "2020-03-07T10:28:54Z")

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Hi all, I have a Problem with the volume rendering. If I try to use the vtkSmartVolumeMapper i get the following Error: ERROR: vtkSmartVolumeMapper (000002A431C3C1B0): Could not find the requested vtkDataArray! 0, 0, -…

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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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## [itk/vtk dimensions and coordinates](https://discourse.vtk.org/t/itk-vtk-dimensions-and-coordinates/2752)

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**Author:** [@Tracy\_Nk](https://discourse.vtk.org/u/Tracy_Nk)\
**Replies:** 1\
**Last updated:** [March 6, 2020, 4:57pm UTC](https://discourse.vtk.org/t/itk-vtk-dimensions-and-coordinates/2752 "2020-03-06T16:57:34Z")

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sorry this might be obvious but I’ve used itkvtkglue to view an ITK image on VTK. now that it is a VTK image, will the coordinates and dimensions (pixels length and width) of the image be identical to the ITK image? Th…

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## [Decimation](https://discourse.vtk.org/t/decimation/2763)

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**Author:** [@steersteer](https://discourse.vtk.org/u/steersteer)\
**Replies:** 1\
**Last updated:** [March 6, 2020, 4:59am UTC](https://discourse.vtk.org/t/decimation/2763 "2020-03-06T04:59:30Z")

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Hi, I’m trying to decimate a mesh because I have far too many triangles for the mesh to be useable. So far I have been using: def Decimation(meshname): reader = vtk.vtkSTLReader() reader.SetFileName(meshnam…

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## [How to tell if a vtkImageData object contains any pixel/voxel data](https://discourse.vtk.org/t/how-to-tell-if-a-vtkimagedata-object-contains-any-pixel-voxel-data/2765)

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**Author:** [@MichelleKline](https://discourse.vtk.org/u/MichelleKline)\
**Replies:** 4\
**Last updated:** [March 5, 2020, 11:42pm UTC](https://discourse.vtk.org/t/how-to-tell-if-a-vtkimagedata-object-contains-any-pixel-voxel-data/2765 "2020-03-05T23:42:18Z")

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Hello, What is the most straight-forward way to determine whether a vtkImageData object is “empty”. In other words, whether or not it contains any pixel/voxel data? Thank you, Michelle K.

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## [How to Isosurface for nc/netcdf Data?](https://discourse.vtk.org/t/how-to-isosurface-for-nc-netcdf-data/2448)

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**Author:** [@Alex1](https://discourse.vtk.org/u/Alex1)\
**Replies:** 8\
**Last updated:** [March 5, 2020, 6:52pm UTC](https://discourse.vtk.org/t/how-to-isosurface-for-nc-netcdf-data/2448 "2020-03-05T18:52:52Z")

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Hi all, I am trying to read a .nc file with the vtkNetCDFCFReader and use a vtkContourFilter on it. But as soon as I use the vtkContourFilter I see nothing but a black window. What am I doing wrong? My Code: string in…

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## [get color array from PolyDataFilter](https://discourse.vtk.org/t/get-color-array-from-polydatafilter/2755)

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**Author:** [@ShaneKirkbride](https://discourse.vtk.org/u/ShaneKirkbride)\
**Replies:** 5\
**Last updated:** [March 5, 2020, 2:47pm UTC](https://discourse.vtk.org/t/get-color-array-from-polydatafilter/2755 "2020-03-05T14:47:10Z")

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I’m trying to get an array of colors and their corresponding vertices from a polyData distance filter similiar to this: https://lorensen.github.io/VTKExamples/site/Cxx/PolyData/DistancePolyDataFilter/ I saw this post bu…

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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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## [Lines -\> Polylines -\> Polygons](https://discourse.vtk.org/t/lines-polylines-polygons/2759)

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**Author:** [@cobo](https://discourse.vtk.org/u/cobo)\
**Replies:** 2\
**Last updated:** [March 5, 2020, 2:11pm UTC](https://discourse.vtk.org/t/lines-polylines-polygons/2759 "2020-03-05T14:11:06Z")

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Maybe this is just a naming question, but what I want to achieve is: Read some linear data that are either already polylines, but maybe also just line segments with common end points that need to be joined first. C…

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## [vtk SliderWidget in Qt environment](https://discourse.vtk.org/t/vtk-sliderwidget-in-qt-environment/2761)

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**Author:** [@lyz](https://discourse.vtk.org/u/lyz)\
**Replies:** 0\
**Last updated:** [March 5, 2020, 12:44pm UTC](https://discourse.vtk.org/t/vtk-sliderwidget-in-qt-environment/2761 "2020-03-05T12:44:22Z")

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I am learning vtk example in Qt environment. I tested this example SliderWidget. I just change the code as below: sliderWidget-\>SetInteractor(this-\>ui-\>qvtkWidget-\>GetInteractor()); However, the SliderWidget doesn’t s…

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## [cap a vtkClipPolyData does not work propertly. Weird behaviour](https://discourse.vtk.org/t/cap-a-vtkclippolydata-does-not-work-propertly-weird-behaviour/2655)

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**Author:** [@zandarina](https://discourse.vtk.org/u/zandarina)\
**Replies:** 3\
**Last updated:** [March 5, 2020, 9:50am UTC](https://discourse.vtk.org/t/cap-a-vtkclippolydata-does-not-work-propertly-weird-behaviour/2655 "2020-03-05T09:50:00Z")

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Hi i´d like to cap the parts i clip and i used the code of this example http://www.vtk.org/Wiki/VTK/Examples/Cxx/Meshes/CapClip And i also tried this: for (int i = 0; i \< (int)clipFilters\_.size(); i++) { clipFil…

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## [MassProperties](https://discourse.vtk.org/t/massproperties/2753)

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**Author:** [@ShaneKirkbride](https://discourse.vtk.org/u/ShaneKirkbride)\
**Replies:** 3\
**Last updated:** [March 4, 2020, 8:54pm UTC](https://discourse.vtk.org/t/massproperties/2753 "2020-03-04T20:54:37Z")

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I’m looking at the vtkMassProperties class. How is the mass computed with no knowledge of the pixel or slice spacing of the PolyData?

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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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## [vtkWindowToImageFilter giving artifacts](https://discourse.vtk.org/t/vtkwindowtoimagefilter-giving-artifacts/2749)

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**Author:** [@aditya-krish](https://discourse.vtk.org/u/aditya-krish)\
**Replies:** 0\
**Last updated:** [March 4, 2020, 5:51am UTC](https://discourse.vtk.org/t/vtkwindowtoimagefilter-giving-artifacts/2749 "2020-03-04T05:51:35Z")

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OS: Ubuntu 18.04 Server I am running an API which processes an input mesh, takes screenshots of it and return some output. Other parts of the screen appearing as ghosts in the screenshot, lower left corner if the disp…

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## [GUISupportQtOpenGL](https://discourse.vtk.org/t/guisupportqtopengl/2733)

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**Author:** [@Jaafar\_Nasrabadi](https://discourse.vtk.org/u/Jaafar_Nasrabadi)\
**Replies:** 3\
**Last updated:** [March 4, 2020, 2:52am UTC](https://discourse.vtk.org/t/guisupportqtopengl/2733 "2020-03-04T02:52:10Z")

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GUISupportQtOpenGL hi. i installed QT5.14.1 (VS 2015 ) with QT offline installer before compiling VTK unstable, but an error occurred. i used vtk-unstable, VS2015(update 1) , cmake 3.16.4 and QT5.14.1( VS 2015) . i used …

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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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## [Using Gradient Filter](https://discourse.vtk.org/t/using-gradient-filter/2734)

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**Author:** [@ShaneKirkbride](https://discourse.vtk.org/u/ShaneKirkbride)\
**Replies:** 1\
**Last updated:** [March 3, 2020, 4:18am UTC](https://discourse.vtk.org/t/using-gradient-filter/2734 "2020-03-03T04:18:33Z")

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I’m trying to use the GradentFilter example: https://vtk.org/Wiki/VTK/Examples/Cxx/PolyData/GradientFilter I can’t get my mesh to show the color changes the way the one in the picture shows. Is there some example data …

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## [Getting sample data to test VTK](https://discourse.vtk.org/t/getting-sample-data-to-test-vtk/2729)

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**Author:** [@phedayat](https://discourse.vtk.org/u/phedayat)\
**Replies:** 2\
**Last updated:** [March 3, 2020, 1:45am UTC](https://discourse.vtk.org/t/getting-sample-data-to-test-vtk/2729 "2020-03-03T01:45:49Z")

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The main reason I’m using VTK is to use VMTK. However, I don’t have any sample data to test VMTK with. Is there any place where I can find sample .vtp or .voi files?

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## [json failures since 2020-01-02](https://discourse.vtk.org/t/json-failures-since-2020-01-02/2702)

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**Author:** [@seanm](https://discourse.vtk.org/u/seanm)\
**Replies:** 2\
**Last updated:** [March 2, 2020, 6:14pm UTC](https://discourse.vtk.org/t/json-failures-since-2020-01-02/2702 "2020-03-02T18:14:59Z")

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Hi all, I haven’t had time to look at VTK in weeks, and was sad to discover today several of my dashboards red since 2020-01-02: https://open.cdash.org/index.php?project=VTK&date=2020-01-02 In file included from /User…

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## [Free Biomedical Image Analysis and Visualization 3-day Course: March 24-26, 2020, Carrboro, NC, USA](https://discourse.vtk.org/t/free-biomedical-image-analysis-and-visualization-3-day-course-march-24-26-2020-carrboro-nc-usa/2422)

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**Author:** [@cory.quammen](https://discourse.vtk.org/u/cory.quammen)\
**Replies:** 3\
**Last updated:** [March 2, 2020, 4:57pm UTC](https://discourse.vtk.org/t/free-biomedical-image-analysis-and-visualization-3-day-course-march-24-26-2020-carrboro-nc-usa/2422 "2020-03-02T16:57:49Z")

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Kitware has organized another free 3-day biomedical image analysis and visualization course to be held March 24-26, 2020, at Kitware’s Carrboro, NC, USA office. The course is designed for clinical researchers and techno…

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## [VTK 8.2.0 - come and get it!](https://discourse.vtk.org/t/vtk-8-2-0-come-and-get-it/174)

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**Author:** [@Dave\_DeMarle](https://discourse.vtk.org/u/Dave_DeMarle)\
**Replies:** 18\
**Last updated:** [March 2, 2020, 10:40am UTC](https://discourse.vtk.org/t/vtk-8-2-0-come-and-get-it/174 "2020-03-02T10:40:45Z")

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For more information check out this kitware blog post.

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## [How to build vtk](https://discourse.vtk.org/t/how-to-build-vtk/2707)

<div class="topic-metadata">

**Author:** [@awa5114](https://discourse.vtk.org/u/awa5114)\
**Replies:** 7\
**Last updated:** [March 2, 2020, 6:36am UTC](https://discourse.vtk.org/t/how-to-build-vtk/2707 "2020-03-02T06:36:39Z")

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I would like to build vtk for two purposes: Run examples/come up with own examples in C++ Contribute to development in case I find a bug or possible enhancement So far I have gone through the following steps: Forked…

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## [Does VTK-8.9 Support GLTFExport?](https://discourse.vtk.org/t/does-vtk-8-9-support-gltfexport/2730)

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**Author:** [@ShaneKirkbride](https://discourse.vtk.org/u/ShaneKirkbride)\
**Replies:** 2\
**Last updated:** [March 2, 2020, 3:12am UTC](https://discourse.vtk.org/t/does-vtk-8-9-support-gltfexport/2730 "2020-03-02T03:12:19Z")

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Hello I’m trying to export a PolyData object to GLTF format. I got the example here: https://lorensen.github.io/VTKExamples/site/Cxx/IO/GLTFExporter/ I get this error in cmake: Skipping GLTFExporter: Could not find t…

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## [\[VTK8.9\] vtkCutter not show scalar information](https://discourse.vtk.org/t/vtk8-9-vtkcutter-not-show-scalar-information/2662)

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**Author:** [@Yue\_JIN](https://discourse.vtk.org/u/Yue_JIN)\
**Replies:** 3\
**Last updated:** [March 2, 2020, 2:34am UTC](https://discourse.vtk.org/t/vtk8-9-vtkcutter-not-show-scalar-information/2662 "2020-03-02T02:34:49Z")

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Hi everybody, I use vtkCutter to show a section of an unstructuredgrid. My code works well in vtk 8.2. But in vtk 8.9, the actor of vtkCutter becomes white like shown in the picture attached. All these actors are rendere…

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## [VTK (pyqt): problem about coordinate conversion: display vs world](https://discourse.vtk.org/t/vtk-pyqt-problem-about-coordinate-conversion-display-vs-world/2727)

<div class="topic-metadata">

**Author:** [@zhang-qiang-github](https://discourse.vtk.org/u/zhang-qiang-github)\
**Replies:** 1\
**Last updated:** [March 1, 2020, 2:07pm UTC](https://discourse.vtk.org/t/vtk-pyqt-problem-about-coordinate-conversion-display-vs-world/2727 "2020-03-01T14:07:19Z")

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I am using VTK in my project, and I meet a problem about the coordinate convertion: from display coordinate vs world coordiante. First, I show a cone and set the window size to (500, 500). Then, I calcualte the world po…

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## [Algorithm to Convert a CT Image to an X-ray image](https://discourse.vtk.org/t/algorithm-to-convert-a-ct-image-to-an-x-ray-image/2726)

<div class="topic-metadata">

**Author:** [@Uncheajax](https://discourse.vtk.org/u/Uncheajax)\
**Replies:** 2\
**Last updated:** [March 1, 2020, 2:03pm UTC](https://discourse.vtk.org/t/algorithm-to-convert-a-ct-image-to-an-x-ray-image/2726 "2020-03-01T14:03:59Z")

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Hello, Can someone assist with the steps or algorithm to convert a CT image to an X-ray image.

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## [Build VTK with TBB](https://discourse.vtk.org/t/build-vtk-with-tbb/2686)

<div class="topic-metadata">

**Author:** [@Max](https://discourse.vtk.org/u/Max)\
**Replies:** 4\
**Last updated:** [February 28, 2020, 4:37pm UTC](https://discourse.vtk.org/t/build-vtk-with-tbb/2686 "2020-02-28T16:37:45Z")

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Hello, can anyone guide me how to build VTK with VTK\_SMP\_IMPLEMENTATION\_TYPE = TBB on Windows? I downloaded TBB from https://github.com/intel/tbb/releases. tbb-2020.1-win.zip Unfortunately, I don’t know which folders…

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