# Support

**URL:** https://discourse.vtk.org/c/support/6.md?page=16

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

**Page:** 17

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## [Window level and width reset issue in vtkresliceimageviewer](https://discourse.vtk.org/t/window-level-and-width-reset-issue-in-vtkresliceimageviewer/14962)

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**Author:** [@christeen](https://discourse.vtk.org/u/christeen)\
**Replies:** 0\
**Last updated:** [December 5, 2024, 4:11am UTC](https://discourse.vtk.org/t/window-level-and-width-reset-issue-in-vtkresliceimageviewer/14962 "2024-12-05T04:11:55Z")

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I have made the MPR application based on the fourpaneviewer and I can manage the window level and width using the left mouse. For example when I changing the window level and width over the axial viewer by using the mous…

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## [How to separate pipeline processing from rendering?](https://discourse.vtk.org/t/how-to-separate-pipeline-processing-from-rendering/14959)

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**Author:** [@Tomasso](https://discourse.vtk.org/u/Tomasso)\
**Replies:** 0\
**Last updated:** [December 4, 2024, 10:46pm UTC](https://discourse.vtk.org/t/how-to-separate-pipeline-processing-from-rendering/14959 "2024-12-04T22:46:12Z")

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My app reads in topographic data from a file then displays a surface either colored by elevation, or the surface colored by geographic slope (user option). My simplistic understanding is that to render a surface a VTK a…

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## [How to create vtkActor without solid representation?](https://discourse.vtk.org/t/how-to-create-vtkactor-without-solid-representation/14952)

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**Author:** [@ugis](https://discourse.vtk.org/u/ugis)\
**Replies:** 2\
**Last updated:** [December 4, 2024, 3:58pm UTC](https://discourse.vtk.org/t/how-to-create-vtkactor-without-solid-representation/14952 "2024-12-04T15:58:16Z")

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Dear VTK developers and users, I am trying to do the following: I create a surface representation based on polygons, which can contain holes (needed to use vtkContourTriangulator, see #14834); Now I want to also displ…

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## [QVTKOpenglnativewidget lag during zoom operation](https://discourse.vtk.org/t/qvtkopenglnativewidget-lag-during-zoom-operation/14940)

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**Author:** [@Manjunath\_AV](https://discourse.vtk.org/u/Manjunath_AV)\
**Replies:** 1\
**Last updated:** [December 2, 2024, 12:49pm UTC](https://discourse.vtk.org/t/qvtkopenglnativewidget-lag-during-zoom-operation/14940 "2024-12-02T12:49:28Z")

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I am using QVTKOpenGLNativeWidget to render 3D DICOM data, but I’ve observed significant lag during zoom operations. Each mouse wheel movement takes 3 to 5 seconds to respond, and CPU usage spikes to 90% during the zoomi…

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## [How Can I use vtk generate a contour band,just like the picture,](https://discourse.vtk.org/t/how-can-i-use-vtk-generate-a-contour-band-just-like-the-picture/14929)

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**Author:** [@shils](https://discourse.vtk.org/u/shils)\
**Replies:** 1\
**Last updated:** [November 28, 2024, 12:14pm UTC](https://discourse.vtk.org/t/how-can-i-use-vtk-generate-a-contour-band-just-like-the-picture/14929 "2024-11-28T12:14:50Z")

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the picture show is what i want , but when i use vtkContourFilter, iOnly the equivalent parts are displayed, and no other parts are displayed

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## [int the vtk9.3.0 ，how can i export video?](https://discourse.vtk.org/t/int-the-vtk9-3-0-how-can-i-export-video/14926)

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**Author:** [@shils](https://discourse.vtk.org/u/shils)\
**Replies:** 4\
**Last updated:** [November 28, 2024, 8:24am UTC](https://discourse.vtk.org/t/int-the-vtk9-3-0-how-can-i-export-video/14926 "2024-11-28T08:24:36Z")

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int the vtk9.3.0 ， I can not find vtkAVIWriter, how can I export a video using vtk?

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## [How to prevent points from disappearing when zooming in?](https://discourse.vtk.org/t/how-to-prevent-points-from-disappearing-when-zooming-in/14903)

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**Author:** [@blocky](https://discourse.vtk.org/u/blocky)\
**Replies:** 5\
**Last updated:** [November 28, 2024, 2:10am UTC](https://discourse.vtk.org/t/how-to-prevent-points-from-disappearing-when-zooming-in/14903 "2024-11-28T02:10:45Z")

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Hi all I am a beginner with VTK, it’s interesting and I’m currently learning through examples. When I try the example of Delaunay2, I noticed that the points disappear when the camera is zoomed in to a certain extent …

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## [Flip the ResliceImageViewer](https://discourse.vtk.org/t/flip-the-resliceimageviewer/14752)

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**Author:** [@christeen](https://discourse.vtk.org/u/christeen)\
**Replies:** 4\
**Last updated:** [November 27, 2024, 10:51am UTC](https://discourse.vtk.org/t/flip-the-resliceimageviewer/14752 "2024-11-27T10:51:23Z")

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I based my code on the FourPaneViewer. In my coronal viewer (vtkResliceImageViewer), the image is displayed, but it appears flipped like a mirror image. I’m trying to correct it to display in the normal orientation. I a…

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## [vtkPythonAlgortim Modified() method - purpose ?](https://discourse.vtk.org/t/vtkpythonalgortim-modified-method-purpose/14922)

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**Author:** [@Nicholas\_Yue](https://discourse.vtk.org/u/Nicholas_Yue)\
**Replies:** 1\
**Last updated:** [November 26, 2024, 11:31pm UTC](https://discourse.vtk.org/t/vtkpythonalgortim-modified-method-purpose/14922 "2024-11-26T23:31:05Z")

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I am learning about vtkAlgorithm via this article. I see a mention of this call self.Modified() I am unable to find any documentation of this method nor is there any similar counterpart on the C++ side of vtkAlgorithm. …

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## [Why does Nvidia graphics show lower usage and performance than Intel graphics?](https://discourse.vtk.org/t/why-does-nvidia-graphics-show-lower-usage-and-performance-than-intel-graphics/14913)

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**Author:** [@PHM](https://discourse.vtk.org/u/PHM)\
**Replies:** 1\
**Last updated:** [November 26, 2024, 7:11pm UTC](https://discourse.vtk.org/t/why-does-nvidia-graphics-show-lower-usage-and-performance-than-intel-graphics/14913 "2024-11-26T19:11:39Z")

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Hi I’m a beginner dealing with VTK for the first time. I was doing a simple GPU test with the Python code below. import time import numpy as np import pyvista as pv #Size of Point Cloud height, width, dim = 480, 6…

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## [Error area picking with vtk and qt](https://discourse.vtk.org/t/error-area-picking-with-vtk-and-qt/14842)

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**Author:** [@hjxy2012](https://discourse.vtk.org/u/hjxy2012)\
**Replies:** 6\
**Last updated:** [November 26, 2024, 3:22am UTC](https://discourse.vtk.org/t/error-area-picking-with-vtk-and-qt/14842 "2024-11-26T03:22:36Z")

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I am using Qt and VTK to select cells in my VTU file. However, the highlighted cells do not match the cells in the area picker. I tried converting the world coordinates of the selected cells to screen coordinates, but th…

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## [Display points and surfaces of polydata](https://discourse.vtk.org/t/display-points-and-surfaces-of-polydata/14907)

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**Author:** [@Julien\_Champagnol](https://discourse.vtk.org/u/Julien_Champagnol)\
**Replies:** 16\
**Last updated:** [November 25, 2024, 7:05pm UTC](https://discourse.vtk.org/t/display-points-and-surfaces-of-polydata/14907 "2024-11-25T19:05:01Z")

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Hi, I’m trying to display the vertices(points) of a mesh along with the polygons with vtk from a vtp file. This is the code I’m using : actor.GetProperty().SetVertexVisibility(visibility) It does not change t…

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## [Problem with Parallel Projection after upgrading to VTK 9.1.0](https://discourse.vtk.org/t/problem-with-parallel-projection-after-upgrading-to-vtk-9-1-0/11169)

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**Author:** [@whereismymoney](https://discourse.vtk.org/u/whereismymoney)\
**Replies:** 24\
**Last updated:** [November 22, 2024, 11:29am UTC](https://discourse.vtk.org/t/problem-with-parallel-projection-after-upgrading-to-vtk-9-1-0/11169 "2024-11-22T11:29:17Z")

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After upgrading to VTK 9.1.0, we have problems when zooming in (with Parallel Projection on). There are artifacts (“cross-hatching,” “Moire patterns,” “aliasing”) that are extremely bad in some cases. Is there a sett…

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## [somebody can help](https://discourse.vtk.org/t/somebody-can-help/14905)

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**Author:** [@zist8888](https://discourse.vtk.org/u/zist8888)\
**Replies:** 1\
**Last updated:** [November 22, 2024, 10:18am UTC](https://discourse.vtk.org/t/somebody-can-help/14905 "2024-11-22T10:18:12Z")

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Continuing the discussion from vtkResliceCursorWidget: output images are cropped:

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## [Offscreen Rendering with VTK 9.4, vtkXOpenGLRenderWindow warnings](https://discourse.vtk.org/t/offscreen-rendering-with-vtk-9-4-vtkxopenglrenderwindow-warnings/14894)

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**Author:** [@biagas](https://discourse.vtk.org/u/biagas)\
**Replies:** 6\
**Last updated:** [November 21, 2024, 3:42pm UTC](https://discourse.vtk.org/t/offscreen-rendering-with-vtk-9-4-vtkxopenglrenderwindow-warnings/14894 "2024-11-21T15:42:01Z")

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I pulled from the release branch yesterday (11-18) and compiled on linux. I didn’t modify any of the OpenGL build settings. I then compiled the OffscreenRendering example to test out how the runtime-choosing of render w…

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## [vtkGradientFilter: no input array?](https://discourse.vtk.org/t/vtkgradientfilter-no-input-array/14899)

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**Author:** [@Tomasso](https://discourse.vtk.org/u/Tomasso)\
**Replies:** 9\
**Last updated:** [November 21, 2024, 12:07am UTC](https://discourse.vtk.org/t/vtkgradientfilter-no-input-array/14899 "2024-11-21T00:07:31Z")

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I’ve written a C++ application that reads and displays topographic data from a file. For the data source I’ve subclassed vtkAbstractPolyDataReader to TopoGridReader. TopoGridReader::GetOutput() contains a vtkPoints obje…

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## [Mapper for transparency](https://discourse.vtk.org/t/mapper-for-transparency/14813)

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**Author:** [@Jens\_Munk\_Hansen](https://discourse.vtk.org/u/Jens_Munk_Hansen)\
**Replies:** 2\
**Last updated:** [November 20, 2024, 9:50pm UTC](https://discourse.vtk.org/t/mapper-for-transparency/14813 "2024-11-20T21:50:01Z")

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I have a situation, where I would like to hide some cells based on a custom array. I know that I add a custom array, threshold and a geometry but it is too slow. Meshes are very large. I was thinking whether it was poss…

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## [Question about Powerwall rendering based on vtk](https://discourse.vtk.org/t/question-about-powerwall-rendering-based-on-vtk/14893)

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**Author:** [@1116](https://discourse.vtk.org/u/1116)\
**Replies:** 4\
**Last updated:** [November 20, 2024, 9:16am UTC](https://discourse.vtk.org/t/question-about-powerwall-rendering-based-on-vtk/14893 "2024-11-20T09:16:04Z")

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I’m wondering what are current practical solutions to use vtk render to support the Powerwall(Powerwall - Wikipedia). Each process will start a vtk rendering window and render specific region of object according to the p…

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## [Reading raw data, using memcpy](https://discourse.vtk.org/t/reading-raw-data-using-memcpy/7215)

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**Author:** [@Parisa\_Rabbani](https://discourse.vtk.org/u/Parisa_Rabbani)\
**Replies:** 12\
**Last updated:** [November 20, 2024, 8:53am UTC](https://discourse.vtk.org/t/reading-raw-data-using-memcpy/7215 "2024-11-20T08:53:28Z")

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Hi All, I am trying to read a volume (1024x2048x2048) from a raw data to render. Initially, I tried VTK image reader, although it’s only able to read (1024x2048x1024) portion of the whole data, I am not sure what is the…

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## [Transforming imagedata via vtkTransformFilter vs. vtkImageReslice](https://discourse.vtk.org/t/transforming-imagedata-via-vtktransformfilter-vs-vtkimagereslice/3824)

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**Author:** [@rjs44](https://discourse.vtk.org/u/rjs44)\
**Replies:** 10\
**Last updated:** [November 19, 2024, 7:56pm UTC](https://discourse.vtk.org/t/transforming-imagedata-via-vtktransformfilter-vs-vtkimagereslice/3824 "2024-11-19T19:56:49Z")

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I have derived a 4x4 transformation matrix t which I want to apply to a 3d vtkImageData. To apply t to the imagedata I use vtkTransformFilter: transform\_filter = vtk.vtkTransformFilter() transform\_filter.SetInputData(i…

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## [ScalarBarWidget interactor](https://discourse.vtk.org/t/scalarbarwidget-interactor/14887)

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**Author:** [@Mordrago](https://discourse.vtk.org/u/Mordrago)\
**Replies:** 4\
**Last updated:** [November 19, 2024, 11:49am UTC](https://discourse.vtk.org/t/scalarbarwidget-interactor/14887 "2024-11-19T11:49:03Z")

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Hello! I have a code: self.scalar\_bar = vtkScalarBarActor() self.scalar\_bar\_widget = vtkScalarBarWidget() self.scalar\_bar\_widget.SetInteractor(self.iren) self.scalar\_bar\_…

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## [How to get vtkDataSet (cells, points, ...) information from a source in VTK-9?](https://discourse.vtk.org/t/how-to-get-vtkdataset-cells-points-information-from-a-source-in-vtk-9/14860)

<div class="topic-metadata">

**Author:** [@Tomasso](https://discourse.vtk.org/u/Tomasso)\
**Replies:** 9\
**Last updated:** [November 19, 2024, 1:03am UTC](https://discourse.vtk.org/t/how-to-get-vtkdataset-cells-points-information-from-a-source-in-vtk-9/14860 "2024-11-19T01:03:21Z")

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I’m writing C++ for VTK-9.3.1. How can an application discover what vtkDataSets are produced by a source, e.g. a third-party subclass of vtkAbstractPolyDataReader? In VTK-8 I could get vtkDataSet information from a sour…

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## [Unable to build VTK 9.4 with Qt 6.8](https://discourse.vtk.org/t/unable-to-build-vtk-9-4-with-qt-6-8/14857)

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**Author:** [@Daan\_Baas](https://discourse.vtk.org/u/Daan_Baas)\
**Replies:** 5\
**Last updated:** [November 18, 2024, 1:39pm UTC](https://discourse.vtk.org/t/unable-to-build-vtk-9-4-with-qt-6-8/14857 "2024-11-18T13:39:20Z")

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Hi there, We have built a certified medical device software product, which is mostly based on VTK combined with ITK, GDCM and Qt toolkits/frameworks. It currently uses VTK 8.2.0, combined with Qt 5.15.2 We’ve been usin…

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## [Configure error with ccmake and cmake?](https://discourse.vtk.org/t/configure-error-with-ccmake-and-cmake/14886)

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**Author:** [@CHENG-HSUAN](https://discourse.vtk.org/u/CHENG-HSUAN)\
**Replies:** 9\
**Last updated:** [November 18, 2024, 1:03pm UTC](https://discourse.vtk.org/t/configure-error-with-ccmake-and-cmake/14886 "2024-11-18T13:03:23Z")

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I followed the VTK documentation step by step to build VTK on Ubuntu 22.04. Here are the required packages I am using the v9.4.0 branch. When I configure with ccmake (using all default build options), it fails to g…

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## [Integration of data inside isosurface](https://discourse.vtk.org/t/integration-of-data-inside-isosurface/14858)

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**Author:** [@Jellby](https://discourse.vtk.org/u/Jellby)\
**Replies:** 3\
**Last updated:** [November 15, 2024, 12:54pm UTC](https://discourse.vtk.org/t/integration-of-data-inside-isosurface/14858 "2024-11-15T12:54:15Z")

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I have some data (electron density) in a structured grid. I can plot the isosurface for different isovalues, and it looks nice. I’d like to integrate the density inside (or outside) the isosurface. Does VTK offer some to…

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## [How to convert a .vtu(Unstructured Grid) file to a .vtk(Rectilinear Grid) file?](https://discourse.vtk.org/t/how-to-convert-a-vtu-unstructured-grid-file-to-a-vtk-rectilinear-grid-file/14872)

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**Author:** [@JNYXR](https://discourse.vtk.org/u/JNYXR)\
**Replies:** 4\
**Last updated:** [November 15, 2024, 7:14am UTC](https://discourse.vtk.org/t/how-to-convert-a-vtu-unstructured-grid-file-to-a-vtk-rectilinear-grid-file/14872 "2024-11-15T07:14:13Z")

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How to convert a .vtu(Unstructured Grid) file to a .vtk(Rectilinear Grid) file?

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## [weighted ICP](https://discourse.vtk.org/t/weighted-icp/14878)

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**Author:** [@maedeh\_kafiyan\_safar](https://discourse.vtk.org/u/maedeh_kafiyan_safar)\
**Replies:** 3\
**Last updated:** [November 15, 2024, 2:40am UTC](https://discourse.vtk.org/t/weighted-icp/14878 "2024-11-15T02:40:37Z")

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Hello, everyone. I use the VTK ICP module to do point-to-surface registration. I want to give some points less weight in ICP as I need them to affect but less than other points. I searched a lot through the ICP module, a…

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## [how to implement touch interaction for vtkimageviwer in QT ?](https://discourse.vtk.org/t/how-to-implement-touch-interaction-for-vtkimageviwer-in-qt/14875)

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**Author:** [@Dhanya](https://discourse.vtk.org/u/Dhanya)\
**Replies:** 0\
**Last updated:** [November 14, 2024, 9:15am UTC](https://discourse.vtk.org/t/how-to-implement-touch-interaction-for-vtkimageviwer-in-qt/14875 "2024-11-14T09:15:22Z")

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I am using vtkimageviwer in QVTKOpenGLNativeWidget , i have created custom mouse interaction for mouse events , for that i used both interactorstyleimage and interactorstyletrackballactor for that and used to switch bet…

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## [How to convert a .vtu(Unstructured Grid) file to a .vtk(Rectilinear Grid) file?](https://discourse.vtk.org/t/how-to-convert-a-vtu-unstructured-grid-file-to-a-vtk-rectilinear-grid-file/14870)

<div class="topic-metadata">

**Author:** [@JNYXR](https://discourse.vtk.org/u/JNYXR)\
**Replies:** 0\
**Last updated:** [November 14, 2024, 3:34am UTC](https://discourse.vtk.org/t/how-to-convert-a-vtu-unstructured-grid-file-to-a-vtk-rectilinear-grid-file/14870 "2024-11-14T03:34:08Z")

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How to convert a .vtu(Unstructured Grid) file to a .vtk(Rectilinear Grid) file?

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## [Segmentation of toothl models in 3D STL format](https://discourse.vtk.org/t/segmentation-of-toothl-models-in-3d-stl-format/10755)

<div class="topic-metadata">

**Author:** [@jiaxuan66680](https://discourse.vtk.org/u/jiaxuan66680)\
**Replies:** 1\
**Last updated:** [November 13, 2024, 11:12am UTC](https://discourse.vtk.org/t/segmentation-of-toothl-models-in-3d-stl-format/10755 "2024-11-13T11:12:46Z")

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Hello everyone, my first post here. I have a human lower alveolar STL model with 14 teeth, here some teeth are connected to each other, how can I use python to separate each tooth individually. Can I try a curvature or …

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