# Latest

**URL:** https://discourse.vtk.org/latest.md?page=188

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

**Page:** 189

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## [qt5+vtk9.0,vtkGenericOpenGLRenderWindow::render() seems to be working incorrectly](https://discourse.vtk.org/t/qt5-vtk9-0-vtkgenericopenglrenderwindow-render-seems-to-be-working-incorrectly/4962)

<div class="topic-metadata">

**Author:** [@Riton](https://discourse.vtk.org/u/Riton)\
**Replies:** 2\
**Last updated:** [January 8, 2021, 7:53am UTC](https://discourse.vtk.org/t/qt5-vtk9-0-vtkgenericopenglrenderwindow-render-seems-to-be-working-incorrectly/4962 "2021-01-08T07:53:41Z")

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I copy an example from github,the name is " SideBySideRenderWindowsQt".But the graphs just flashed and disappeared.then if I call function qvtkwidegt-\>GetRenderWindow()-\>GetRenderers()-\>Render(),the graphs will appear ag…

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## [Linker error while building application with VTK component](https://discourse.vtk.org/t/linker-error-while-building-application-with-vtk-component/4957)

<div class="topic-metadata">

**Author:** [@Olumide](https://discourse.vtk.org/u/Olumide)\
**Replies:** 3\
**Last updated:** [January 7, 2021, 2:45am UTC](https://discourse.vtk.org/t/linker-error-while-building-application-with-vtk-component/4957 "2021-01-07T02:45:24Z")

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I am trying to build an application, called niftysim, which has optional visualization component that relies on VTK dependency. niftysim builds okay but when I enable the visualization component, in CMAKE, as shown below …

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## [Vector field from three scalar components](https://discourse.vtk.org/t/vector-field-from-three-scalar-components/4959)

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**Author:** [@razoumov](https://discourse.vtk.org/u/razoumov)\
**Replies:** 2\
**Last updated:** [January 7, 2021, 1:50am UTC](https://discourse.vtk.org/t/vector-field-from-three-scalar-components/4959 "2021-01-07T01:50:53Z")

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Hello, I have three vtkDoubleArray 3D scalar fields in my Python VTK pipeline: bx = resample.GetOutput().GetPointData().GetArray("Bx") by = resample.GetOutput().GetPointData().GetArray("By") bz = resample.GetOutput().G…

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## [3D Transformation using VTK and Paraview](https://discourse.vtk.org/t/3d-transformation-using-vtk-and-paraview/4569)

<div class="topic-metadata">

**Author:** [@pravindi](https://discourse.vtk.org/u/pravindi)\
**Replies:** 3\
**Last updated:** [January 6, 2021, 3:22pm UTC](https://discourse.vtk.org/t/3d-transformation-using-vtk-and-paraview/4569 "2021-01-06T15:22:34Z")

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Using Paraview’s python shell and VTK, I’m trying to perform a complex transformation on a series of specific 3D facial landmark points (about 10-15 points). These points have been separately collected and are stored in …

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## [After updating VTK from 6.3.0 to 8.1.1，renderer became hidden in my project](https://discourse.vtk.org/t/after-updating-vtk-from-6-3-0-to-8-1-1-renderer-became-hidden-in-my-project/4955)

<div class="topic-metadata">

**Author:** [@yujhuang](https://discourse.vtk.org/u/yujhuang)\
**Replies:** 1\
**Last updated:** [January 6, 2021, 11:12am UTC](https://discourse.vtk.org/t/after-updating-vtk-from-6-3-0-to-8-1-1-renderer-became-hidden-in-my-project/4955 "2021-01-06T11:12:30Z")

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Problem: RenderingWindow shows nothing while interactor style functions are working after version update I already have developed a working software base on ITK-SNAP with VTK 6.3 , ITK 4.8.2, cmake 2.8.12, MSVC2013 and …

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## [Having difficulties understanding how to control what I am rendering in 2D](https://discourse.vtk.org/t/having-difficulties-understanding-how-to-control-what-i-am-rendering-in-2d/4934)

<div class="topic-metadata">

**Author:** [@Tiago\_D\_Agostini](https://discourse.vtk.org/u/Tiago_D_Agostini)\
**Replies:** 11\
**Last updated:** [January 6, 2021, 12:45am UTC](https://discourse.vtk.org/t/having-difficulties-understanding-how-to-control-what-i-am-rendering-in-2d/4934 "2021-01-06T00:45:17Z")

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Hello. I have been trying to do somethign that shoudl be very simple . I am loading a dicom image (ok, done) and render it to a buffer (already did it to a file, and will handle the buffer target later). But I canno…

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## [vtkPVDReader](https://discourse.vtk.org/t/vtkpvdreader/4952)

<div class="topic-metadata">

**Author:** [@aowen](https://discourse.vtk.org/u/aowen)\
**Replies:** 2\
**Last updated:** [January 5, 2021, 3:56pm UTC](https://discourse.vtk.org/t/vtkpvdreader/4952 "2021-01-05T15:56:41Z")

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I noticed that Paraview contains a vtkPVDReader module. Are there any plans to move this out of Paraview and into the VTK library? I didn’t see any obvious dependencies on Paraview when I glanced through the file (I admi…

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## [VTK Plot Window Freezes Main GUI](https://discourse.vtk.org/t/vtk-plot-window-freezes-main-gui/4950)

<div class="topic-metadata">

**Author:** [@oduncu90](https://discourse.vtk.org/u/oduncu90)\
**Replies:** 0\
**Last updated:** [January 4, 2021, 1:48pm UTC](https://discourse.vtk.org/t/vtk-plot-window-freezes-main-gui/4950 "2021-01-04T13:48:58Z")

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I have a program that is written in Python. GUI uses GTK. I plot something by using VTK and it works. But main GUI freezes and other buttons, etc do not work. I have tried multithreading but it still freezes. Maybe Pytho…

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## [New reader in Paraview](https://discourse.vtk.org/t/new-reader-in-paraview/4944)

<div class="topic-metadata">

**Author:** [@halowine](https://discourse.vtk.org/u/halowine)\
**Replies:** 1\
**Last updated:** [January 4, 2021, 9:50am UTC](https://discourse.vtk.org/t/new-reader-in-paraview/4944 "2021-01-04T09:50:33Z")

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Hello, I want to add a new reader in Paraview which is implemented in VTK. Do I need to wait the release of VTK with my modification before going to Paraview or can I make both pull request now (on each gitlab repositor…

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## [Protected Features in VTK](https://discourse.vtk.org/t/protected-features-in-vtk/4945)

<div class="topic-metadata">

**Author:** [@oduncu90](https://discourse.vtk.org/u/oduncu90)\
**Replies:** 1\
**Last updated:** [January 3, 2021, 11:49pm UTC](https://discourse.vtk.org/t/protected-features-in-vtk/4945 "2021-01-03T23:49:15Z")

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There are some features which are protected and they do not work when used. For example: MoveOrigin() from Plane Widget. It does not work. What is the reason? Are there any solutions to use them? Note: I am not a prog…

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## [Setting VTK Window Always On Top](https://discourse.vtk.org/t/setting-vtk-window-always-on-top/4947)

<div class="topic-metadata">

**Author:** [@oduncu90](https://discourse.vtk.org/u/oduncu90)\
**Replies:** 1\
**Last updated:** [January 3, 2021, 6:42pm UTC](https://discourse.vtk.org/t/setting-vtk-window-always-on-top/4947 "2021-01-03T18:42:52Z")

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Are there any methods to show VTK window always on top? VTK: 8.2 Python: 3.8.6 OS: Windows 10

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## [How to understand the Image Position and vtkImageData.GetOrigin()?](https://discourse.vtk.org/t/how-to-understand-the-image-position-and-vtkimagedata-getorigin/4946)

<div class="topic-metadata">

**Author:** [@zhang-qiang-github](https://discourse.vtk.org/u/zhang-qiang-github)\
**Replies:** 1\
**Last updated:** [January 3, 2021, 5:13pm UTC](https://discourse.vtk.org/t/how-to-understand-the-image-position-and-vtkimagedata-getorigin/4946 "2021-01-03T17:13:59Z")

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It’s difficult for me to understand the Image Position (0018, 5100) and the vtkImageData.GetOrigin(). Then, I show it as following: import vtk, time from vedo import Point img = vtk.vtkDICOMImageReader() img.SetFileNam…

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## [error when writing binary VTK files](https://discourse.vtk.org/t/error-when-writing-binary-vtk-files/4487)

<div class="topic-metadata">

**Author:** [@qzxuhui](https://discourse.vtk.org/u/qzxuhui)\
**Replies:** 8\
**Last updated:** [January 3, 2021, 10:42am UTC](https://discourse.vtk.org/t/error-when-writing-binary-vtk-files/4487 "2021-01-03T10:42:14Z")

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Hi everyone, I want to generate binary vtk file. I write a code that can first generate correct ascii vtk file, then do some modification on that, let it can generate correct binary vtk file. I face the problem when co…

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## [split screen to two fullscreen render window](https://discourse.vtk.org/t/split-screen-to-two-fullscreen-render-window/4911)

<div class="topic-metadata">

**Author:** [@SArbabi](https://discourse.vtk.org/u/SArbabi)\
**Replies:** 6\
**Last updated:** [January 2, 2021, 7:17pm UTC](https://discourse.vtk.org/t/split-screen-to-two-fullscreen-render-window/4911 "2021-01-02T19:17:13Z")

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I’m splitting screen to two parts each for a fullscreenrenderwindow like this: fullScreenRenderer.getContainer().style.height = "50%" fullScreenRenderer.resize() fullScreenRenderer2.getContainer().style.height = "50%" f…

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## [vtkSeedWidget - add from file.](https://discourse.vtk.org/t/vtkseedwidget-add-from-file/4939)

<div class="topic-metadata">

**Author:** [@DominionSoftware](https://discourse.vtk.org/u/DominionSoftware)\
**Replies:** 3\
**Last updated:** [January 2, 2021, 3:52pm UTC](https://discourse.vtk.org/t/vtkseedwidget-add-from-file/4939 "2021-01-02T15:52:25Z")

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I’d like to restore the crosshairs I placed on an image with vtkSeedWidget; But I’m not sure the best way. It seems to be oriented only for user interaction, which works fine, but I’d like to restore the seeds the user p…

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## [Why reader.GetPixelSpacing() return (0.83, 0.83, 0)?](https://discourse.vtk.org/t/why-reader-getpixelspacing-return-0-83-0-83-0/4940)

<div class="topic-metadata">

**Author:** [@zhang-qiang-github](https://discourse.vtk.org/u/zhang-qiang-github)\
**Replies:** 4\
**Last updated:** [January 2, 2021, 3:06pm UTC](https://discourse.vtk.org/t/why-reader-getpixelspacing-return-0-83-0-83-0/4940 "2021-01-02T15:06:51Z")

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I want to use vtk to obtain the pixel spacing of image, and the code is: reader = vtk.vtkDICOMImageReader() reader.SetDirectoryName(tempFolder) reader.Update() spacing = reader.GetPixelSp…

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## [Colored Volume from Tiffstack/MultiImageTiff](https://discourse.vtk.org/t/colored-volume-from-tiffstack-multiimagetiff/4909)

<div class="topic-metadata">

**Author:** [@BastianJuelich](https://discourse.vtk.org/u/BastianJuelich)\
**Replies:** 7\
**Last updated:** [January 2, 2021, 10:22am UTC](https://discourse.vtk.org/t/colored-volume-from-tiffstack-multiimagetiff/4909 "2021-01-02T10:22:29Z")

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Hello vtk community, first of all: Thank you for the great VTK Framework, which is an amazing Tool! As a beginner i am just starting a first project using vtk and python to show a 3D representation/rendering from a Tif…

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## [vtkProbeFilter speed vtkImageData vs. vtkStructuredGrid](https://discourse.vtk.org/t/vtkprobefilter-speed-vtkimagedata-vs-vtkstructuredgrid/4928)

<div class="topic-metadata">

**Author:** [@gatti](https://discourse.vtk.org/u/gatti)\
**Replies:** 3\
**Last updated:** [December 30, 2020, 6:32pm UTC](https://discourse.vtk.org/t/vtkprobefilter-speed-vtkimagedata-vs-vtkstructuredgrid/4928 "2020-12-30T18:32:52Z")

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Hi all, Im posting because I have an analysis that performed one way (with vtkImageData) is very fast and another (vtkStructuredGrid) is insanely slow. I have a polydata that I project a vector from (using normals at e…

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## [Turntable Interactor](https://discourse.vtk.org/t/turntable-interactor/4922)

<div class="topic-metadata">

**Author:** [@rich](https://discourse.vtk.org/u/rich)\
**Replies:** 3\
**Last updated:** [December 30, 2020, 3:11pm UTC](https://discourse.vtk.org/t/turntable-interactor/4922 "2020-12-30T15:11:02Z")

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In vtk.js is it be possible to stop the rolling which occurs when navigating a model - it would make navigating the models a whole lot simpler… see request previously posted on gitlab also explaining the feature request……

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## [Embedding VTK in GTK Window by Using Python](https://discourse.vtk.org/t/embedding-vtk-in-gtk-window-by-using-python/4925)

<div class="topic-metadata">

**Author:** [@oduncu90](https://discourse.vtk.org/u/oduncu90)\
**Replies:** 0\
**Last updated:** [December 30, 2020, 1:03pm UTC](https://discourse.vtk.org/t/embedding-vtk-in-gtk-window-by-using-python/4925 "2020-12-30T13:03:14Z")

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I want to embed VTK object in GTK window. I want to draw a cylinder which is explained in this page. It is plotted in a seperate window. But I want to plot it in a GTK gui generated by Glade. I have a windows 10 x64 inst…

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## [How to accelerate the Render()?](https://discourse.vtk.org/t/how-to-accelerate-the-render/4912)

<div class="topic-metadata">

**Author:** [@zhang-qiang-github](https://discourse.vtk.org/u/zhang-qiang-github)\
**Replies:** 7\
**Last updated:** [December 30, 2020, 5:17am UTC](https://discourse.vtk.org/t/how-to-accelerate-the-render/4912 "2020-12-30T05:17:53Z")

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The pipelien of my project is: ... windowLevel = vtk.vtkImageMapToWindowLevelColors() imageActor = vtk.vtkImageActor() imageActor.GetMapper().SetInputConnection(windowLevel.GetOutputPort()) ren = vtk.vtkRenderer() ren.…

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## [Color Mapping Discrete Contours](https://discourse.vtk.org/t/color-mapping-discrete-contours/4913)

<div class="topic-metadata">

**Author:** [@rich](https://discourse.vtk.org/u/rich)\
**Replies:** 1\
**Last updated:** [December 29, 2020, 6:47pm UTC](https://discourse.vtk.org/t/color-mapping-discrete-contours/4913 "2020-12-29T18:47:24Z")

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Hi, I am trying to recreate a similar example using vtk.js to that shown in pyvista (see target example below) where the color scale can be set to discrete values for scalars within a particular range. I am having troub…

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## [The 16bit tiff image always shows white regardless of the pixel value.](https://discourse.vtk.org/t/the-16bit-tiff-image-always-shows-white-regardless-of-the-pixel-value/4907)

<div class="topic-metadata">

**Author:** [@Kim\_William](https://discourse.vtk.org/u/Kim_William)\
**Replies:** 1\
**Last updated:** [December 29, 2020, 2:31pm UTC](https://discourse.vtk.org/t/the-16bit-tiff-image-always-shows-white-regardless-of-the-pixel-value/4907 "2020-12-29T14:31:43Z")

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Hi all. I have a question about the 16bit tiff image. sample.tif (144.7 KB) If I load it on the ImageJ, the image shows from black to white value depends on the pixel value. But if I load it on the VTK sample code,…

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## [Interactor Start() blocking execution](https://discourse.vtk.org/t/interactor-start-blocking-execution/1095)

<div class="topic-metadata">

**Author:** [@marcomusy](https://discourse.vtk.org/u/marcomusy)\
**Replies:** 10\
**Last updated:** [December 29, 2020, 12:05am UTC](https://discourse.vtk.org/t/interactor-start-blocking-execution/1095 "2020-12-29T00:05:58Z")

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Is there a way (in python) to start the vtkRenderWindowInteractor in a different process so that the execution flow is not blocked? Maybe with the vtkMultiThreader class? Thanks

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## [how to display the vtk file?](https://discourse.vtk.org/t/how-to-display-the-vtk-file/4900)

<div class="topic-metadata">

**Author:** [@zmgdzz](https://discourse.vtk.org/u/zmgdzz)\
**Replies:** 5\
**Last updated:** [December 28, 2020, 9:34am UTC](https://discourse.vtk.org/t/how-to-display-the-vtk-file/4900 "2020-12-28T09:34:46Z")

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hi, I am new about the vtk, my purpose is to read 3d vtk file and display it using vtk, however, there is no view at all. Here is my program, Does anyone know the reason? Thanks! import vtk aRenderer=vtk.vtkRenderer() …

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## [How to Segment 3D Volume？](https://discourse.vtk.org/t/how-to-segment-3d-volume/4906)

<div class="topic-metadata">

**Author:** [@wulicheng](https://discourse.vtk.org/u/wulicheng)\
**Replies:** 1\
**Last updated:** [December 28, 2020, 7:30am UTC](https://discourse.vtk.org/t/how-to-segment-3d-volume/4906 "2020-12-28T07:30:27Z")

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How to Segment the 3D picture like the flowing:

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## [Problems with Stereo Rendering on MacOS with Qt UI](https://discourse.vtk.org/t/problems-with-stereo-rendering-on-macos-with-qt-ui/4902)

<div class="topic-metadata">

**Author:** [@TheAmazingDurp](https://discourse.vtk.org/u/TheAmazingDurp)\
**Replies:** 0\
**Last updated:** [December 27, 2020, 2:49pm UTC](https://discourse.vtk.org/t/problems-with-stereo-rendering-on-macos-with-qt-ui/4902 "2020-12-27T14:49:42Z")

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So for the past 3 weeks I have been able to use Stereo Rendering on my Macbook running Catalina. However, some days ago it started acting up and whenever I use it with a button click it doesn’t render in the Qt frame but…

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## [ExtractVOI unable to slice in sagittal or coronal views](https://discourse.vtk.org/t/extractvoi-unable-to-slice-in-sagittal-or-coronal-views/4896)

<div class="topic-metadata">

**Author:** [@charlessillett](https://discourse.vtk.org/u/charlessillett)\
**Replies:** 0\
**Last updated:** [December 26, 2020, 7:40pm UTC](https://discourse.vtk.org/t/extractvoi-unable-to-slice-in-sagittal-or-coronal-views/4896 "2020-12-26T19:40:48Z")

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Hi, I am trying to use the vtkExtractVOI object with its method SetVOI to slice my 3D Nifti image in the axial, coronal and sagittal planes. Axial slicing works however sagittal and coronal slicings do not render any pa…

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## [DICOM data has negative spacing value](https://discourse.vtk.org/t/dicom-data-has-negative-spacing-value/4891)

<div class="topic-metadata">

**Author:** [@Frank\_Gao](https://discourse.vtk.org/u/Frank_Gao)\
**Replies:** 3\
**Last updated:** [December 26, 2020, 4:49am UTC](https://discourse.vtk.org/t/dicom-data-has-negative-spacing-value/4891 "2020-12-26T04:49:54Z")

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Hello, I am trying to load a DICOM dataset using vtk-dicom or GDCM. The volume rendering is never right (only show one plane at the lower Z plane. I found out the output from the reader has spacing values as: spacing\[2\]…

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## [Loading lookup table from .vtk file in vtk.js](https://discourse.vtk.org/t/loading-lookup-table-from-vtk-file-in-vtk-js/4890)

<div class="topic-metadata">

**Author:** [@orestispanago](https://discourse.vtk.org/u/orestispanago)\
**Replies:** 0\
**Last updated:** [December 24, 2020, 5:39pm UTC](https://discourse.vtk.org/t/loading-lookup-table-from-vtk-file-in-vtk-js/4890 "2020-12-24T17:39:22Z")

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I am trying to visualize some .vtk files containing lines and their lookup table. I have successfully loaded and rendered a .vtk file using PolyDataReader, This is my code: import 'vtk.js/Sources/favicon'; import vtkAc…

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