# Support

**URL:** https://discourse.vtk.org/c/support/6.md?page=64

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

**Page:** 65

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## [How to use the SelectExamples](https://discourse.vtk.org/t/how-to-use-the-selectexamples/8756)

<div class="topic-metadata">

**Author:** [@Dwight98](https://discourse.vtk.org/u/Dwight98)\
**Replies:** 3\
**Last updated:** [June 23, 2022, 8:14am UTC](https://discourse.vtk.org/t/how-to-use-the-selectexamples/8756 "2022-06-23T08:14:04Z")

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I want to use the SelectExamples to look through some examples about vtk class which i need,but i don’t know where can modify the vtk\_class and language,I ran the official example code directly and got the following erro…

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## [How to get gradual transition between discrete LUT colors?](https://discourse.vtk.org/t/how-to-get-gradual-transition-between-discrete-lut-colors/9736)

<div class="topic-metadata">

**Author:** [@Tomasso](https://discourse.vtk.org/u/Tomasso)\
**Replies:** 7\
**Last updated:** [November 4, 2022, 12:30am UTC](https://discourse.vtk.org/t/how-to-get-gradual-transition-between-discrete-lut-colors/9736 "2022-11-04T00:30:50Z")

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I am writing an app with VTK-9.3.0 to display seafloor bathymetry. I would like to assign a colormap so that color varies between discrete color values in a gradual way as shown in the figure on the left, using discrete …

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## [vtkLASReader()](https://discourse.vtk.org/t/vtklasreader/438)

<div class="topic-metadata">

**Author:** [@clairecita](https://discourse.vtk.org/u/clairecita)\
**Replies:** 5\
**Last updated:** [March 19, 2019, 12:47am UTC](https://discourse.vtk.org/t/vtklasreader/438 "2019-03-19T00:47:02Z")

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Hi, I saw somewhere that vtk has a reader for .las files (lidar data) (vtkLASReader) but when I try to use it it says that there is no such attribute. What am I missing ?

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## [Cell picker using HardwareSelector](https://discourse.vtk.org/t/cell-picker-using-hardwareselector/9700)

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**Author:** [@MarKara](https://discourse.vtk.org/u/MarKara)\
**Replies:** 3\
**Last updated:** [November 3, 2022, 12:49pm UTC](https://discourse.vtk.org/t/cell-picker-using-hardwareselector/9700 "2022-11-03T12:49:09Z")

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I know this question is raised before but I still cannot find definite answer how to use hardwareselector. I’m using ActiViz 9.2 and have the same problem discussed here How to select a hexahedral cell using HardwareSe…

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## [After add actor to render, can i change the actor data real time ?](https://discourse.vtk.org/t/after-add-actor-to-render-can-i-change-the-actor-data-real-time/9724)

<div class="topic-metadata">

**Author:** [@herman](https://discourse.vtk.org/u/herman)\
**Replies:** 2\
**Last updated:** [November 3, 2022, 7:53am UTC](https://discourse.vtk.org/t/after-add-actor-to-render-can-i-change-the-actor-data-real-time/9724 "2022-11-03T07:53:22Z")

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Dear vtk users: As we know, after add actor to render, we can change the properties of the actor. Now I tried to change the data of the actor,but it does not work. My code is as below: //////////////////////////////…

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## [GetBounds() fails with NaN points in VTK9](https://discourse.vtk.org/t/getbounds-fails-with-nan-points-in-vtk9/4351)

<div class="topic-metadata">

**Author:** [@banesullivan](https://discourse.vtk.org/u/banesullivan)\
**Replies:** 10\
**Last updated:** [November 2, 2022, 10:24pm UTC](https://discourse.vtk.org/t/getbounds-fails-with-nan-points-in-vtk9/4351 "2022-11-02T22:24:30Z")

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Did vtkWarpScalar change in the 9.x release of VTK? Take this example dataset: surface.vtp (3.8 MB) import vtk reader = vtk.vtkXMLPolyDataReader() reader.SetFileName("surface.vtp") reader.Update() surface = reader.Get…

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## [How to "append show" in vtk?](https://discourse.vtk.org/t/how-to-append-show-in-vtk/9713)

<div class="topic-metadata">

**Author:** [@herman](https://discourse.vtk.org/u/herman)\
**Replies:** 4\
**Last updated:** [November 2, 2022, 1:54am UTC](https://discourse.vtk.org/t/how-to-append-show-in-vtk/9713 "2022-11-02T01:54:32Z")

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Dear vtk users: I want to render an object. But at this moment, I only have a part data of the object, I want to render this part first, when i get other parts of the object , just need append to render ? I don't know…

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## [data files from VTKData-9.0.3.tar.gz](https://discourse.vtk.org/t/data-files-from-vtkdata-9-0-3-tar-gz/6407)

<div class="topic-metadata">

**Author:** [@Ricardo\_M\_Picado](https://discourse.vtk.org/u/Ricardo_M_Picado)\
**Replies:** 5\
**Last updated:** [November 1, 2022, 11:56pm UTC](https://discourse.vtk.org/t/data-files-from-vtkdata-9-0-3-tar-gz/6407 "2022-11-01T23:56:08Z")

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Hi, does anyone know how to use files (extension .sha512) from VTKData-9.0.3.tar.gz ? Thanks, Ricardo

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## [Inconsistency with returned ScalarType in vtkPointData (from vtk 9.0.3 onwards)?](https://discourse.vtk.org/t/inconsistency-with-returned-scalartype-in-vtkpointdata-from-vtk-9-0-3-onwards/9304)

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**Author:** [@Seun](https://discourse.vtk.org/u/Seun)\
**Replies:** 1\
**Last updated:** [September 20, 2022, 10:00pm UTC](https://discourse.vtk.org/t/inconsistency-with-returned-scalartype-in-vtkpointdata-from-vtk-9-0-3-onwards/9304 "2022-09-20T22:00:56Z")

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Hello everyone, Does anyone know if by chance something changed in vtkPointData with respect to retrieving its scalars. I’m not quite sure of what I’m observing in my application and would like to get to the bottom of i…

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## [libvtkInteractionStyle-9.0.so: undefined reference to \`vtkExtractEdges::New()' platform is ubuntu20.04](https://discourse.vtk.org/t/libvtkinteractionstyle-9-0-so-undefined-reference-to-vtkextractedges-new-platform-is-ubuntu20-04/9709)

<div class="topic-metadata">

**Author:** [@carl](https://discourse.vtk.org/u/carl)\
**Replies:** 1\
**Last updated:** [November 1, 2022, 1:01pm UTC](https://discourse.vtk.org/t/libvtkinteractionstyle-9-0-so-undefined-reference-to-vtkextractedges-new-platform-is-ubuntu20-04/9709 "2022-11-01T13:01:11Z")

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in makefile :-L/home/Projects/3rdParty/vtk/lib -lvtkInteractionStyle-9.0 while compiled the project，run into a link error: libvtkInteractionStyle-9.0.so: undefined reference to \`vtkExtractEdges::New()’ btw, platform i…

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## [VTKImageReslice: Slow performance](https://discourse.vtk.org/t/vtkimagereslice-slow-performance/1281)

<div class="topic-metadata">

**Author:** [@Abhishek\_Gupta](https://discourse.vtk.org/u/Abhishek_Gupta)\
**Replies:** 10\
**Last updated:** [November 1, 2022, 3:21am UTC](https://discourse.vtk.org/t/vtkimagereslice-slow-performance/1281 "2022-11-01T03:21:24Z")

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Hello Group, I am having performance issues while extracting SAGGITAL/CORONAL planes using VTKImageReslice. Each call to VTKImageReslice-\>GetOutput() takes 5-7 ms. The volume used has the following properties: Dimensi…

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## [How are non-flat polygons converted to triangles for display?](https://discourse.vtk.org/t/how-are-non-flat-polygons-converted-to-triangles-for-display/9694)

<div class="topic-metadata">

**Author:** [@SpareSimian](https://discourse.vtk.org/u/SpareSimian)\
**Replies:** 3\
**Last updated:** [October 31, 2022, 8:55pm UTC](https://discourse.vtk.org/t/how-are-non-flat-polygons-converted-to-triangles-for-display/9694 "2022-10-31T20:55:51Z")

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I’m displaying a stack of vtkQuad like a floating set of sheets of paper, using a vtkPolyData to hold them. Any polygon with more than 3 points might not lie in a plane, of course, and these will likely not, due to the n…

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## [undefined reference to vtkAOSDataArrayTemplate](https://discourse.vtk.org/t/undefined-reference-to-vtkaosdataarraytemplate/9643)

<div class="topic-metadata">

**Author:** [@BlueKnight7](https://discourse.vtk.org/u/BlueKnight7)\
**Replies:** 4\
**Last updated:** [October 31, 2022, 5:40pm UTC](https://discourse.vtk.org/t/undefined-reference-to-vtkaosdataarraytemplate/9643 "2022-10-31T17:40:32Z")

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I have MSYS2 installed on my Windows 10 box. I’ve installed vtk via pacman with mingw-w64-x86\_64-vtk; this is vtk 9.2.2. I’m using gcc 12.2 and is the only version of gcc that I currently have available in the MSYS2 ins…

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## [vtkImageData: SetScalarComponentFromDouble do not change GetScalarRange](https://discourse.vtk.org/t/vtkimagedata-setscalarcomponentfromdouble-do-not-change-getscalarrange/9703)

<div class="topic-metadata">

**Author:** [@zhang-qiang-github](https://discourse.vtk.org/u/zhang-qiang-github)\
**Replies:** 2\
**Last updated:** [October 31, 2022, 4:18pm UTC](https://discourse.vtk.org/t/vtkimagedata-setscalarcomponentfromdouble-do-not-change-getscalarrange/9703 "2022-10-31T16:18:32Z")

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For a vtkImageData, I want to modify the scalar using SetScalarComponentFromDouble. But, I find the GetScalarRange do not return the correct result after SetScalarComponentFromDouble. My test code is: import vtkmodules…

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## [Can I pre-allocate a vtkCellArray?](https://discourse.vtk.org/t/can-i-pre-allocate-a-vtkcellarray/9695)

<div class="topic-metadata">

**Author:** [@SpareSimian](https://discourse.vtk.org/u/SpareSimian)\
**Replies:** 2\
**Last updated:** [October 29, 2022, 9:10pm UTC](https://discourse.vtk.org/t/can-i-pre-allocate-a-vtkcellarray/9695 "2022-10-29T21:10:57Z")

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I’m already pre-sizing my vtkPoints array with the number of points I know I’ll need. I know how many cells (vtkQuad for my app) I’ll need so is there a way to optimize my vtkCellArray allocation in the same way? I haven…

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## [Creating text with different colors in single actor](https://discourse.vtk.org/t/creating-text-with-different-colors-in-single-actor/9690)

<div class="topic-metadata">

**Author:** [@leon1122](https://discourse.vtk.org/u/leon1122)\
**Replies:** 0\
**Last updated:** [October 28, 2022, 6:30pm UTC](https://discourse.vtk.org/t/creating-text-with-different-colors-in-single-actor/9690 "2022-10-28T18:30:56Z")

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I am trying to create a text actor using vtkTextActor and vtkTextProperty more or less as shown in this example. Is there any way to make the words “Hello” and “World!” different colors without resorting to putting them …

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## [How to get the real boundary of the model?](https://discourse.vtk.org/t/how-to-get-the-real-boundary-of-the-model/9689)

<div class="topic-metadata">

**Author:** [@claude](https://discourse.vtk.org/u/claude)\
**Replies:** 0\
**Last updated:** [October 28, 2022, 3:45am UTC](https://discourse.vtk.org/t/how-to-get-the-real-boundary-of-the-model/9689 "2022-10-28T03:45:33Z")

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Hi everyone, I’m using vtkFeatureEdges to get model boundaries.Is there any method to eliminate the boundary caused by holes?

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## [Depth buffer?](https://discourse.vtk.org/t/depth-buffer/9688)

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**Author:** [@llobera](https://discourse.vtk.org/u/llobera)\
**Replies:** 0\
**Last updated:** [October 27, 2022, 3:36pm UTC](https://discourse.vtk.org/t/depth-buffer/9688 "2022-10-27T15:36:51Z")

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Does anyone know whether vtk handles a 24 or 32 bit depth buffer? If 24 bits is there a way to change it to 32 bits?

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## [Interactive wordcloud](https://discourse.vtk.org/t/interactive-wordcloud/9671)

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**Author:** [@Shree\_Lakshmi\_Ramesh](https://discourse.vtk.org/u/Shree_Lakshmi_Ramesh)\
**Replies:** 3\
**Last updated:** [October 27, 2022, 10:49am UTC](https://discourse.vtk.org/t/interactive-wordcloud/9671 "2022-10-27T10:49:07Z")

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Hi I’m trying to create an interactive wordcloud, for eg. clicking the words prints the word or prints all the sentences to which they belong. Is there any way I could achieve this? Thank you

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## [How to set the fixed width/height for vtkScalarBarActor?](https://discourse.vtk.org/t/how-to-set-the-fixed-width-height-for-vtkscalarbaractor/9676)

<div class="topic-metadata">

**Author:** [@zhang-qiang-github](https://discourse.vtk.org/u/zhang-qiang-github)\
**Replies:** 2\
**Last updated:** [October 27, 2022, 9:42am UTC](https://discourse.vtk.org/t/how-to-set-the-fixed-width-height-for-vtkscalarbaractor/9676 "2022-10-27T09:42:52Z")

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I am using vtkScalarBarActor in my application. However, the width/height of vtkScalarBarActor is changing when the render window is changed. For example: For example, the width of vtkScalarBarActor of second fig…

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## [What kind of plane can be used as the input of vtkSelectPolyData?](https://discourse.vtk.org/t/what-kind-of-plane-can-be-used-as-the-input-of-vtkselectpolydata/9687)

<div class="topic-metadata">

**Author:** [@claude](https://discourse.vtk.org/u/claude)\
**Replies:** 0\
**Last updated:** [October 27, 2022, 9:41am UTC](https://discourse.vtk.org/t/what-kind-of-plane-can-be-used-as-the-input-of-vtkselectpolydata/9687 "2022-10-27T09:41:34Z")

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Hi , Can plane be used as the input of vtkSelectPolyData? I use vtkPlane as input data of vtkSelectPolyData,but it doesn’t work.What can i do if i want to get an irregular plane from vtkPoints by using vtkSelectPolyData…

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## [VtkImplicitPlaneWidget2: Color bleeding](https://discourse.vtk.org/t/vtkimplicitplanewidget2-color-bleeding/9686)

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**Author:** [@Synfony](https://discourse.vtk.org/u/Synfony)\
**Replies:** 0\
**Last updated:** [October 26, 2022, 5:23pm UTC](https://discourse.vtk.org/t/vtkimplicitplanewidget2-color-bleeding/9686 "2022-10-26T17:23:50Z")

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Hi, If I try to move the plane where there is another colored plane color bleeding is happening. As you can see from the image that the implicit plane (the white one) if I move and it gets superimposed on the top an…

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## [How to use XDMF3 reader in python](https://discourse.vtk.org/t/how-to-use-xdmf3-reader-in-python/9682)

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**Author:** [@RemDelaporteMathurin](https://discourse.vtk.org/u/RemDelaporteMathurin)\
**Replies:** 1\
**Last updated:** [October 26, 2022, 1:21pm UTC](https://discourse.vtk.org/t/how-to-use-xdmf3-reader-in-python/9682 "2022-10-26T13:21:31Z")

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Hi all, We are trying to include an XDMF3 reader in pyvista, however we can’t find a way to import xdmf3 from vtkmodules, only xdmf2 from vtkmodules.vtkIOXdmf2 import vtkXdmfReader The following doesn’t work: from vt…

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## [how to export table data into excel](https://discourse.vtk.org/t/how-to-export-table-data-into-excel/9669)

<div class="topic-metadata">

**Author:** [@we\_create](https://discourse.vtk.org/u/we_create)\
**Replies:** 2\
**Last updated:** [October 26, 2022, 2:31am UTC](https://discourse.vtk.org/t/how-to-export-table-data-into-excel/9669 "2022-10-26T02:31:52Z")

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Hi . I want to export table data into excel file . can anyone plz help . with vtk (c++)

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## [The New Volumetric Rendering is Beautiful (Also Happy Halloween)](https://discourse.vtk.org/t/the-new-volumetric-rendering-is-beautiful-also-happy-halloween/9675)

<div class="topic-metadata">

**Author:** [@fraseyboo](https://discourse.vtk.org/u/fraseyboo)\
**Replies:** 6\
**Last updated:** [October 25, 2022, 5:37pm UTC](https://discourse.vtk.org/t/the-new-volumetric-rendering-is-beautiful-also-happy-halloween/9675 "2022-10-25T17:37:15Z")

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So this isn’t really a support post but I just wanted to say how impressive the volumetric rendering is now, the effort you guys put into visual effects like PBR & SSAO is really impressive and has helped me make some re…

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## [Select the invisible points and dye them](https://discourse.vtk.org/t/select-the-invisible-points-and-dye-them/9661)

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**Author:** [@claude](https://discourse.vtk.org/u/claude)\
**Replies:** 2\
**Last updated:** [October 25, 2022, 1:34am UTC](https://discourse.vtk.org/t/select-the-invisible-points-and-dye-them/9661 "2022-10-25T01:34:14Z")

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Hi everyone, I am using vtkSelectVisiblePoints to get invisible points from a vtkPolyData, and i can get the pointsset i want.Now i want to change the color of the original polydata through the output pointsset,what sho…

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## [Visualize the Leaning Tower of Pisa (or San Francisco's Millennium Tower)](https://discourse.vtk.org/t/visualize-the-leaning-tower-of-pisa-or-san-franciscos-millennium-tower/9665)

<div class="topic-metadata">

**Author:** [@SpareSimian](https://discourse.vtk.org/u/SpareSimian)\
**Replies:** 4\
**Last updated:** [October 24, 2022, 10:45pm UTC](https://discourse.vtk.org/t/visualize-the-leaning-tower-of-pisa-or-san-franciscos-millennium-tower/9665 "2022-10-24T22:45:18Z")

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I’m looking for inspiration on how to present my data. I can do the math part. What I’m looking for is how to present it. Imagine a multistory building of equally-spaced floors, either cylindrical (like a grain silo) or…

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## [More than 250k of labels](https://discourse.vtk.org/t/more-than-250k-of-labels/9664)

<div class="topic-metadata">

**Author:** [@Mesh](https://discourse.vtk.org/u/Mesh)\
**Replies:** 1\
**Last updated:** [October 24, 2022, 10:43pm UTC](https://discourse.vtk.org/t/more-than-250k-of-labels/9664 "2022-10-24T22:43:41Z")

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Hi, I am using vtkLabelPlacementMapper to display more than 250k of labels, it shows labels but the zoom in and zoom out …ect is to slow. Is there a better solution the improve rendering and interactivity performance? …

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## [Building vtk-9.2.2 with vtkDicom requires running cmake twice](https://discourse.vtk.org/t/building-vtk-9-2-2-with-vtkdicom-requires-running-cmake-twice/9659)

<div class="topic-metadata">

**Author:** [@Carol\_Capek](https://discourse.vtk.org/u/Carol_Capek)\
**Replies:** 5\
**Last updated:** [October 24, 2022, 6:05pm UTC](https://discourse.vtk.org/t/building-vtk-9-2-2-with-vtkdicom-requires-running-cmake-twice/9659 "2022-10-24T18:05:13Z")

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Hello, I tried to build vtk-9.2.2 the other day and ran into a problem when running: cmake ../ -GNinja -DCMAKE\_INSTALL\_PREFIX=/opt/VTK-9.2.2 -DBUILD\_SHARED\_LIBS=false -DCMAKE\_BUILD\_TYPE=Release -DVTK\_MODULE\_ENABLE\_VTK\_…

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## [Qt6 + VTK9: Objects always rotating](https://discourse.vtk.org/t/qt6-vtk9-objects-always-rotating/9658)

<div class="topic-metadata">

**Author:** [@andrsd](https://discourse.vtk.org/u/andrsd)\
**Replies:** 1\
**Last updated:** [October 24, 2022, 3:41pm UTC](https://discourse.vtk.org/t/qt6-vtk9-objects-always-rotating/9658 "2022-10-24T15:41:45Z")

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When I build the minimal Qt VTK app example\[1\] with Qt 6.2.4 and VTK 9.2.2, the displayed object rotates such that it follows the mouse cursor. If I build just a standalone VTK app (like BorderWidgetQt \[2\]) I get the ex…

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