# Support

**URL:** https://discourse.vtk.org/c/support/6.md?page=113

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

**Page:** 114

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

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

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**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)

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**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)

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**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)

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

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**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)

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**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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## [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)

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**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)

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**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)

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**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)

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**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)

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**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)

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**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)

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**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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## [VTK provide three different world point converted from three methods with one display point](https://discourse.vtk.org/t/vtk-provide-three-different-world-point-converted-from-three-methods-with-one-display-point/4843)

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**Author:** [@zhang-qiang-github](https://discourse.vtk.org/u/zhang-qiang-github)\
**Replies:** 4\
**Last updated:** [December 24, 2020, 1:46pm UTC](https://discourse.vtk.org/t/vtk-provide-three-different-world-point-converted-from-three-methods-with-one-display-point/4843 "2020-12-24T13:46:39Z")

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I am using VTK in my project, and I need to get the world point from a display point. I find three method: vtkPropPicker, vtkCellPicker, vtkCoordinate. But I find they return different world point for the same display p…

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## [VTK: vtkSurfaceReconstructionFilter Inaccurate rendering results in 3D](https://discourse.vtk.org/t/vtk-vtksurfacereconstructionfilter-inaccurate-rendering-results-in-3d/4884)

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**Author:** [@Pandapan](https://discourse.vtk.org/u/Pandapan)\
**Replies:** 1\
**Last updated:** [December 24, 2020, 12:47pm UTC](https://discourse.vtk.org/t/vtk-vtksurfacereconstructionfilter-inaccurate-rendering-results-in-3d/4884 "2020-12-24T12:47:39Z")

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There are many points in 3D, we use them for volume rendering by vtkSurfaceReconstructionFilter，But the results seem ugly, and I wonder what the problem is? Here are my code and results： auto colors = vtkSmartPointer\<…

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## [question about the type transfer from vtkDataObject to vtkPolyData](https://discourse.vtk.org/t/question-about-the-type-transfer-from-vtkdataobject-to-vtkpolydata/4888)

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**Author:** [@1116](https://discourse.vtk.org/u/1116)\
**Replies:** 0\
**Last updated:** [December 24, 2020, 6:00am UTC](https://discourse.vtk.org/t/question-about-the-type-transfer-from-vtkdataobject-to-vtkpolydata/4888 "2020-12-24T06:00:47Z")

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Hello, I try to gather the polydata generated by different processes into one processes based on vtkMPIController, and then aggregate them into one data set for further processing by following code: ...... std:…

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## [Gets the dimensions of an explicit structured grid](https://discourse.vtk.org/t/gets-the-dimensions-of-an-explicit-structured-grid/4871)

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**Author:** [@rodrigomologni](https://discourse.vtk.org/u/rodrigomologni)\
**Replies:** 3\
**Last updated:** [December 23, 2020, 11:53am UTC](https://discourse.vtk.org/t/gets-the-dimensions-of-an-explicit-structured-grid/4871 "2020-12-23T11:53:16Z")

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Support, How can I get the dimensions of an explicit structured grid by means of Python code, please? print(grid.GetDimensions()) TypeError: GetDimensions() takes exactly 1 argument (0 given) GetDimensions returns not…

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## [What version of OpenGL does VTK use?](https://discourse.vtk.org/t/what-version-of-opengl-does-vtk-use/4868)

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**Author:** [@Brady\_Hales](https://discourse.vtk.org/u/Brady_Hales)\
**Replies:** 1\
**Last updated:** [December 23, 2020, 10:16am UTC](https://discourse.vtk.org/t/what-version-of-opengl-does-vtk-use/4868 "2020-12-23T10:16:17Z")

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I am using the latest version of VTK but I think I am having trouble with some of the OpenGL libraries with my graphics card. Does anybody know what version of OpenGL is used with the latest VTK libraries? Thanks,

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## [VTK: how to set the threshold for vtkPropPicker](https://discourse.vtk.org/t/vtk-how-to-set-the-threshold-for-vtkproppicker/4833)

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**Author:** [@zhang-qiang-github](https://discourse.vtk.org/u/zhang-qiang-github)\
**Replies:** 3\
**Last updated:** [December 23, 2020, 2:38am UTC](https://discourse.vtk.org/t/vtk-how-to-set-the-threshold-for-vtkproppicker/4833 "2020-12-23T02:38:17Z")

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When click the mouse, vtkPropPicker can decide whether a actor is selected. I wonder whether can we set a threshold to decide whether the actor is selected? For example, if the distance between the mouse click position …

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## [How to add the color of gray image to point cloud](https://discourse.vtk.org/t/how-to-add-the-color-of-gray-image-to-point-cloud/4856)

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**Author:** [@Ethan](https://discourse.vtk.org/u/Ethan)\
**Replies:** 3\
**Last updated:** [December 21, 2020, 7:16pm UTC](https://discourse.vtk.org/t/how-to-add-the-color-of-gray-image-to-point-cloud/4856 "2020-12-21T19:16:02Z")

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When I use the settablevalue function in vtklookuptable, I can only set the value of RGBA, but my image is a gray image. How can I set the color to the point cloud?

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## [coincident topology offset parameters](https://discourse.vtk.org/t/coincident-topology-offset-parameters/4836)

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**Author:** [@andreasbuykx](https://discourse.vtk.org/u/andreasbuykx)\
**Replies:** 2\
**Last updated:** [December 21, 2020, 5:17pm UTC](https://discourse.vtk.org/t/coincident-topology-offset-parameters/4836 "2020-12-21T17:17:25Z")

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I am working on migrating our FEA application from VTK 8.1.1 to VTK 9.0.1. As a result of the changes to how coincident topology resolution is implemented I get a lot of changes. sometimes they are improvements but un…

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## [Python example for GLTF export/import](https://discourse.vtk.org/t/python-example-for-gltf-export-import/4596)

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**Author:** [@desheng](https://discourse.vtk.org/u/desheng)\
**Replies:** 4\
**Last updated:** [December 21, 2020, 2:04pm UTC](https://discourse.vtk.org/t/python-example-for-gltf-export-import/4596 "2020-12-21T14:04:55Z")

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Is it possible to provide an example in Python like in CXX https://lorensen.github.io/VTKExamples/site/Cxx/IO/GLTFExporter/ for GLTF export/import? Thanks!

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## [image pixel values and background for 3d rendering](https://discourse.vtk.org/t/image-pixel-values-and-background-for-3d-rendering/4162)

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**Author:** [@YolkandWhite](https://discourse.vtk.org/u/YolkandWhite)\
**Replies:** 7\
**Last updated:** [December 21, 2020, 9:53am UTC](https://discourse.vtk.org/t/image-pixel-values-and-background-for-3d-rendering/4162 "2020-12-21T09:53:16Z")

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Hi, I am new to VTK. I have a question about how the pixel value works in 3d rendering. what I’m trying to do is segment the ROI region of stacked 2d image and 3d volume render the ROIs. If the pixel value is 0, does …

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## [vtkAxesActor Fails to Render at Some Angles](https://discourse.vtk.org/t/vtkaxesactor-fails-to-render-at-some-angles/4864)

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**Author:** [@nchampag](https://discourse.vtk.org/u/nchampag)\
**Replies:** 2\
**Last updated:** [September 9, 2025, 4:04pm UTC](https://discourse.vtk.org/t/vtkaxesactor-fails-to-render-at-some-angles/4864 "2025-09-09T16:04:57Z")

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After upgrading from 8.2.0 to 9.0.1, VTK AxesActors do not render at certain angles. Here is a Python script that demonstrates this: # This script demonstrates that the vtkAxesActor is not drawn between phi = 91 degr…

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## [vtkAppendPolyData does not include the scalar information](https://discourse.vtk.org/t/vtkappendpolydata-does-not-include-the-scalar-information/4850)

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**Author:** [@zandarina](https://discourse.vtk.org/u/zandarina)\
**Replies:** 2\
**Last updated:** [December 20, 2020, 11:33am UTC](https://discourse.vtk.org/t/vtkappendpolydata-does-not-include-the-scalar-information/4850 "2020-12-20T11:33:21Z")

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Hello, I am tryng to append two polydatas with scalar info so according to the class information if both have scalar information the output should also include it. But i am trying it of many ways and the results does no…

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## [extracting (or creating) vtkSmartPointer from Python-wrapped VTK object](https://discourse.vtk.org/t/extracting-or-creating-vtksmartpointer-from-python-wrapped-vtk-object/2407)

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**Author:** [@stefanseefeld](https://discourse.vtk.org/u/stefanseefeld)\
**Replies:** 2\
**Last updated:** [December 20, 2020, 2:03am UTC](https://discourse.vtk.org/t/extracting-or-creating-vtksmartpointer-from-python-wrapped-vtk-object/2407 "2020-12-20T02:03:04Z")

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I’d like to integrate VTK/Python into my own project, which uses a mix of C++ and Python code. I need to call functions that take vtkSmartPointer arguments with object references I have extracted from VTK/Python wrapper…

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## [Image Data to Point Cloud](https://discourse.vtk.org/t/image-data-to-point-cloud/4841)

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**Author:** [@sandress](https://discourse.vtk.org/u/sandress)\
**Replies:** 3\
**Last updated:** [December 19, 2020, 5:10pm UTC](https://discourse.vtk.org/t/image-data-to-point-cloud/4841 "2020-12-19T17:10:57Z")

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Hi everyone, I’m searching for a way to create a semi-random point cloud thats density in specific areas is defined by an underlying CT image. E.g. in areas with an high HU-value the point cloud should be dense as in lo…

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## [Deform a CT image volume using the vtkImageReslice](https://discourse.vtk.org/t/deform-a-ct-image-volume-using-the-vtkimagereslice/4848)

<div class="topic-metadata">

**Author:** [@isuruwi](https://discourse.vtk.org/u/isuruwi)\
**Replies:** 4\
**Last updated:** [December 17, 2020, 8:03pm UTC](https://discourse.vtk.org/t/deform-a-ct-image-volume-using-the-vtkimagereslice/4848 "2020-12-17T20:03:24Z")

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I want to apply transformations such as translate, scale, rotation to a given 3D CT image volume (mhd format). For that I have used vtkImageReslice function as below. But the output seems not correctly deformed as expect…

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## [Coordinates of point in a 3D Image](https://discourse.vtk.org/t/coordinates-of-point-in-a-3d-image/4837)

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**Author:** [@Luis\_Carlos\_Carneiro](https://discourse.vtk.org/u/Luis_Carlos_Carneiro)\
**Replies:** 1\
**Last updated:** [December 16, 2020, 10:37pm UTC](https://discourse.vtk.org/t/coordinates-of-point-in-a-3d-image/4837 "2020-12-16T22:37:45Z")

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Dear All, Having a displayed 3D volume image (with interactor) and with a click with the mouse above the image, how it can be obtained that point (of the click) coordinate in the 3D referential? Thanks, Luís Gonçalves …

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